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BUILDING TECHNOLOGIES PROGRAM
Life-Cycle Assessment of
Energy and Environmental
Impacts of LED Lighting
Products
Part 2: LED Manufacturing and Performance
June 2012
Prepared for:
Solid-State Lighting Program
Building Technologies Program
Office of Energy Efficiency and
Renewable Energy
U.S. Department of Energy
Prepared by:
Pacific Northwest National
Laboratory
N14 Energy Limited
Page i
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the U.S. Government.
Neither the U.S. Government, nor any agency thereof, nor any of their employees, nor any of their
contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes
any legal liability or responsibility for the accuracy, completeness, or usefulness of any information,
apparatus, product, or process disclosed, or represents that its use would not infringe privately owned
rights. Reference herein to any specific commercial product, process, or service by trade name,
trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement,
recommendation, or favoring by the U.S. Government or any agency, contractor or subcontractor
thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those
of the U.S. Government or any agency thereof. Furthermore, the authors are solely responsible for
any errors or omissions contained in this report.
AUTHORS
Michael J. Scholand, LC Heather E. Dillon, Ph.D.
N14 Energy Limited Pacific Northwest National Laboratory
Page ii
ACKNOWLEDGEMENTS
The authors of this report would like to thank Yole Développement (www.yole.fr ) and System Plus
Consulting (www.systemplus.fr ) for their kind and valuable support and assistance with this project.
In particular, we are grateful to Jeff Perkins of Yole Développement and Romain Fraux of System
Plus Consulting for their responsiveness to questions and guidance. The authors would also like to
express their sincere thanks to OSRAM Opto Semiconductors GmbH for their cooperation and
willingness to provide information relating to their own Life-Cycle Assessment of an LED lamp
conducted in 2009 and to OSRAM SYLVANIA INC for facilitating the process. Their contributions
greatly facilitated our understanding of the materials, processes and issues surrounding the
manufacturing and assembly of an LED lamp.
The authors would also like to express their appreciation to members of the technical review
committee who participated in a review of the reports, methods and results, which added to the
integrity of the estimates. These members include:
Mary Ashe Navigant, Inc.
Makarand Chipalkatti OSRAM SYLVANIA
Brad Hollomon Compa Industries, Inc.
Lesley Snowden-Swan Pacific Northwest National Laboratory
Leena Tähkämö Aalto University and Université Paul Sabatier (Toulouse III)
Jason Tuenge Pacific Northwest National Laboratory
COMMENTS
Pacific Northwest National Laboratory and the U.S. Department of Energy are interested in receiving
comments on the material presented in this report. If you have any comments, please submit them to
Marc Ledbetter at the following address:
Marc Ledbetter
Pacific Northwest National Laboratory
PO Box 999
Richland, WA 99352
marc.ledbetter(at)pnnl.gov
Page iii
ERRATA
August 13, 2012
Readers of the original report posed some questions about how the report handled recycled content in
some of the material use analyzed. Several small editorial changes were made to clarify how recycled
content was treated by the authors in the analysis. These changes did not result in any changes to the
calculations, tables, graphs, findings or conclusions to the body of work as originally published. The
effect of the changes was to improve the clarity of presentation with respect to the aluminum
feedstock used for heat sinks and the disposal of packaging following the purchase of a lamp. The
following shows changes made to these three paragraphs in this revised report:
In Executive Summary, p. 4:
Recovery and recycling of materials – there is a lack of information in the public domain
about the extent to which materials used in the manufacturing of LEDs are reused and
recycled. If these materials are recovered, processed and then reused, this would reduce the
per unit production environmental impacts. However, this version of the study assumes new
materials or materials with the lowest percentage recycled content are used at all stages of the
LCA process, thus providing a conservative estimate of the impacts. In other words, tTo the
extent that materials are recovered and recycled, the environmental impacts will be less than
those reported in this study.
In section 4.2, p. 14:
5. End-of-Life - the final stage of a life cycle is the end-of-life stage which reflects what
happens to the lighting products when they have stopped working and are no longer required.
The end-of life phase takes into account any other integral parts of a product’s life-cycle,
most notably the box and packaging. There is also the question of whether to give a process
credit for any end-of life recycling which could, for example, reduce reliance on raw
materials. However, if a particular process assumes a reduced impact due to the
incorporation of recycled materials or the use of recycling processes in the waste stream, to
add process credits back into the impact calculation on top of those reduced impacts this
might constitute double-counting. For this study therefore, any benefits associated with
recycling packaging have been excluded from the system boundary taken into account by
using recycling processes in the waste stream.
In section 4.4, p. 21:
• Recovery and recycling of materials – there is a lack of information in the public
domain about the extent to which materials used in the manufacturing of LEDs are
reused and recycled. If these materials are recovered, processed and then reused, this
would reduce the per unit production environmental impacts. However, in this
version of the study, we are assumesing new materials or materials with the lowest
percentage recycled content are used at all stages of the LCA process, thus providing
a conservative estimate of the impacts. In other words, tTo the extent that materials
are recovered and recycled, the environmental impacts will be less than those
reported in this study.
Page iv
Table of Contents
1 Executive Summary ............................................................................................................................. 1
2 Introduction ......................................................................................................................................... 6
3 Life-Cycle Assessment Methodology .................................................................................................. 9
3.1 International LCA Standards ............................................................................................................ 9
3.2 Brief Overview of an LCA ................................................................................................................. 9
4 Goal and Scope .................................................................................................................................. 12
4.1 Goal Statement .............................................................................................................................. 12
4.2 Scope .............................................................................................................................................. 12
4.3 Bounding the Scope of the Study .................................................................................................. 14
4.3.1 Substrate ................................................................................................................................ 14
4.3.2 LED Type ................................................................................................................................. 16
4.3.3 White Light ............................................................................................................................. 18
4.3.4 The Representative LED for the Manufacturing Unit Processes ............................................ 20
4.4 Limitations of the Study ................................................................................................................. 20
4.5 Critical Review ................................................................................................................................ 21
5 Life Cycle Inventory Analysis ............................................................................................................. 23
5.1 Inputs ............................................................................................................................................. 23
5.2 LED Manufacturing ........................................................................................................................ 24
5.2.1 Substrate Production.............................................................................................................. 25
5.2.2 LED Die Fabrication ................................................................................................................ 27
5.2.3 Packaged LED Assembly ......................................................................................................... 33
5.3 LED Lamp Analysis .......................................................................................................................... 35
5.4 Incandescent Lamp Analysis .......................................................................................................... 39
5.5 Compact Fluorescent Lamp Analysis ............................................................................................. 41
6 Life Cycle Impact Assessment Indicators .......................................................................................... 44
7 Life Cycle Assessment Results ........................................................................................................... 48
7.1 Discussion of Life Cycle Assessment Results .................................................................................. 53
7.2 Comparative Results Between the Lamps ..................................................................................... 54
7.3 Summary of the Environmental Impacts ....................................................................................... 57
7.3.1 Comparison with DOE Part 1 Study Findings ......................................................................... 60
7.4 Data Quality Assessment ............................................................................................................... 61
7.4.1 Comparison of Ecoinvent LED with DOE LED Impact Estimates ............................................. 62
8 Critical Review ................................................................................................................................... 64
9 Recommendations ............................................................................................................................. 65
10 APPENDIX A: Sensitivity Analysis ...................................................................................................... 66
11 References ......................................................................................................................................... 70
Page v
List of Tables
Table 2-1. Key Publications Reviewed in DOE’s Part 1 Report (DOE, 2012a) ............................................... 7
Table 4-1. Summary of the Life-Cycle Assessment Goal for this Report .................................................... 12
Table 4-2. Wafer Sizes and the Corresponding Surface Area and Yield of LED Chips ................................. 15
Table 4-3. Summary of LED Colors and Common Chemistries ................................................................... 17
Table 4-4. White Light LED Package Segmentation .................................................................................... 18
Table 5-1. Performance Parameters for Lamps Considered in this Analysis .............................................. 24
Table 5-2. Steps Associated with Sapphire Wafer Substrate Manufacture ................................................ 26
Table 5-3. Energy and Material Consumption for Three-Inch Sapphire Wafer Manufacturing ................. 27
Table 5-4. Steps Associated with Gallium Nitride Epitaxy .......................................................................... 28
Table 5-5. Post-Epitaxy Steps Associated with LED Die Fabrication ........................................................... 30
Table 5-6. Energy and Material Consumption for LED Die Fabrication ...................................................... 32
Table 5-7. Steps Associated with LED Packaging and Assembly ................................................................. 33
Table 5-8. Energy and Material Consumption for LED Packaging Assembly .............................................. 34
Table 5-9. LCA Inventory for the 12.5 Watt LED Lamp in 2012 .................................................................. 35
Table 5-10. Changes to LCA Inputs for LED Lamp Manufacturing in 2017 ................................................. 38
Table 5-11. LCA Inventory for the 60 Watt Incandescent Lamp ................................................................. 39
Table 5-12. LCA Inventory for the 15 Watt Integrally Ballasted Compact Fluorescent Lamp .................... 41
Table 6-1. LCA Environmental Indicators Selected for this Analysis ........................................................... 44
Table 7-1. Life Cycle Impacts of the 60W Incandescent Lamp ................................................................... 49
Table 7-2. Life Cycle Impacts of the Compact Fluorescent Lamp ............................................................... 50
Table 7-3. Life Cycle Impacts of the 2012 LED Lamp .................................................................................. 51
Table 7-4. Life Cycle Impacts of the 2017 LED Lamp .................................................................................. 52
Table 7-5. Air-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service ............... 54
Table 7-6. Water-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service ......... 55
Table 7-7. Soil-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service .............. 56
Table 7-8. Resource-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service ..... 56
Table 7-9. Data Quality Ranking Based on Highest Value for this Goal and Scope (5 high, 1 low) ............ 61
Table 7-10. Comparison of Ecoinvent LED and this Study’s LED Manufacturing Impacts .......................... 63
Page vi
List of Figures
Figure 1-1. Life-Cycle Assessment Impacts of the Lamps Analyzed Relative to Incandescent ..................... 2
Figure 1-2. Life-Cycle Assessment Impacts of the Lamps Analyzed Relative to CFL ..................................... 3
Figure 2-1. Life-Cycle Energy of Incandescent Lamps, CFLs, and LED Lamps (DOE, 2012a) ......................... 8
Figure 3-1. Key Aspects of an LCA Study (ISO 2006) ................................................................................... 10
Figure 4-1. System boundary of the Life Cycle Assessment of this Study (Part 2) ..................................... 13
Figure 4-2. Comparison of MOCVD Reactor Tray, 2” versus 6” wafers ...................................................... 15
Figure 4-3. Trends in Diameter of Sapphire Substrates for LED Manufacturing ........................................ 16
Figure 4-4. General Types of White Light Emitting Diode (LED) Devices .................................................... 19
Figure 4-5. Flow of Data Gathering and Analysis for this Research Project ............................................... 22
Figure 5-1. Three Major Stages of Packaged LED Manufacturing .............................................................. 25
Figure 5-2. Example of the Finished Packaged LED, the Philips Luxeon Rebel ........................................... 34
Figure 7-1. Proportions of the Life Cycle Impacts for the 60W Incandescent Lamp .................................. 49
Figure 7-2. Proportions of the Life Cycle Impacts for the Compact Fluorescent Lamp .............................. 50
Figure 7-3. Proportions of the Life Cycle Impacts for the 2012 LED Lamp ................................................. 51
Figure 7-4. Proportions of the Life Cycle Impacts for the 2017 LED Lamp ................................................. 52
Figure 7-5. Life-Cycle Assessment Impacts of the Lamps Analyzed Relative to Incandescent ................... 58
Figure 7-6. Life-Cycle Assessment Impacts of the CFL and LED Lamps Analyzed (Detail) .......................... 59
Figure 7-7. Life Cycle Assessment Primary Energy for Lamps in Part 2 Study ............................................ 60
Page vii
Acronyms and Abbreviations
Ag silver
Al aluminum
AlN aluminum nitride
Al2O3 aluminum oxide (alumina)
Au gold
CCT correlated color temperature
Ce cerium
CH4 methane
CO2 carbon dioxide
CVD chemical vapor deposition
DOE Department of Energy
ECD electrochemical deposition
ESD electrostatic discharge
GaN gallium nitride
g grams
H2 hydrogen
H2O2 hydrogen peroxide
HCl hydrochloric acid
HF hydrofluoric acid
ISO International Standards Organisation
kWh kilowatt-hour
LCA life cycle assessment
LCD liquid crystal display
LCI life cycle inventory
LCIA life cycle impact assessment
LED light emitting diode
LLO laser lift off
lm lumen
mA milliampere
mm millimeter (m-3)
MOCVD metalorganic chemical vapor deposition
N2 nitrogen
nm nanometers (m-9)
NH3 ammonia
NH4OH ammonium hydroxide
Ni nickel
NOx oxide of nitrogen
O2 oxygen
pcLED phosphor converting LED
PNNL Pacific Northwest National Laboratory
PVD physical vapor deposition
R&D research and development
SF6 sulfur hexafluoride
SiC silicon carbide
SiH4 silicon tetrahydride (silane)
Sn tin
SO2 sulfur dioxide
SSL solid state lighting
Ti titanium
TMAl trimethylaluminum
TMGa trimethylgallium
TMIn trimethylindium
UK United Kingdom
μm micrometer (m-6)
UPW ultra-pure water
U.S. United States
UV ultraviolet
V volts
W watts
W tungsten
YAG yttrium aluminum garnet
ZnSe zinc selenide
Page 1
1 Executive Summary
The report LED Manufacturing and Performance covers the second part of a larger U.S. Department of
Energy (DOE) project to assess the life-cycle environmental and resource costs in the manufacturing,
transport, use, and disposal of light-emitting diode (LED) lighting products in relation to comparable
traditional lighting technologies. The assessment comprises three parts:
• Part 1: Review of the Lifecycle Energy Consumption of Incandescent, Compact Fluorescent and
LED Lamps. Comparison of the total life-cycle energy consumed by LED and other lamp types
based on existing life-cycle assessment (LCA) literature. This report was published in February
2012 and is available on U.S. DOE website:
http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/2012_LED_Lifecycle_Report.pdf
• Part 2: LED Manufacturing and Performance. This study develops a conservative LCA method
for considering both the direct and indirect material and process inputs to fabricate, ship, operate
and dispose of LED products in 2012 and estimated for 2017. An LCA comparison to an
incandescent lamp and a compact fluorescent lamp (CFL) is provided.
• Part 3: LED Environmental Testing. The purchase, disassembly and chemical testing of LED and
conventional lighting products to study whether potentially hazardous materials are present in
concentrations that exceed hazardous waste regulatory thresholds.
Part 1 of the overall effort reviewed existing LCA literature to determine the range of energy consumption
and downstream energy savings. The report compared existing life-cycle energy consumption of an LED
lamp product to incandescent lamp and CFL technologies based on 10 literature studies. Part 1 of the
work provided the following results:
1. A detailed literature review of more than 25 existing LCA studies in this field.
2. A summary of the LCA process and methodology.
3. A meta-analysis based on a functional unit of 20 million lumen-hours for incandescent, halogen,
CFL and LED lamps.
The Part 1 report concluded that the life cycle energy consumption of LED lamps and CFLs are similar at
approximately 3,900 MJ per 20 million lumen-hours. Incandescent lamps consume significantly more
energy (approximately 15,100 MJ per 20 million lumen-hours). The authors also concluded that the use
phase is the most important contributor to the energy consumption, followed by manufacturing of the
lamps and finally transportation (less than 1% of energy consumption). One key issue identified in the
report is the high uncertainty in energy consumption associated with the manufacturing process estimates
in surveyed literature range from 0.1% to 27% of the total life-cycle energy consumption.
Part 2 of the project (this report) uses the conclusions from Part 1 as a point of departure to focus on two
objectives: producing a more detailed and conservative assessment of the manufacturing process and
providing a comparative LCA with other lighting products based on the improved manufacturing analysis
and taking into consideration a wider range of environmental impacts. In this study, we first analyzed the
manufacturing process for a white-light LED lamp (based on a sapphire-substrate, blue-light, gallium-
nitride LED package pumping a yellow phosphor applied to the lamp envelope), to understand the
impacts of the manufacturing process. We then conducted a comparative LCA, looking at the impacts
associated with the Philips EnduraLED and comparing those to a CFL and an incandescent lamp. The
comparison took into account the Philips EnduraLED as it is now in 2012 and then projected forward
Page 2
what it might be in 2017, accounting for some of the anticipated improvements in LED manufacturing,
performance and driver electronics.
Overall, this study confirmed that energy-in-use is the dominant environmental impact, with the 15-watt
CFL and 12.5-watt LED lamps performing better than the 60-watt incandescent lamp. These three lamps
all produce approximately the same light output (~850 lumens), but the environmental impacts associated
with the incandescent are markedly more significant than the CFL and LED lamps because of the energy-
in-use phase of the life-cycle.
In order to evaluate the fifteen impact measures of interest across the four lamp types considered, “spider”
graphs were prepared. Each of the fifteen impacts is represented (and labeled) by a spoke in the web, and
the relative impacts of each lamp type are plotted on the graph. The lamp type having the greatest impact
of the set analyzed (incandescent, in this case) defines the scale represented by the outer circle at the
greatest distance from the center of the web. The other products are then normalized to that impact, so the
distance from the center denotes the severity of the impact relative to the incandescent lamp. In other
words, those sources with the least impact will have their circle close to the center and those with the
greatest impact would be on the outer perimeter of the web. The data plotted in this graph are normalized
for the quantity of lighting service, measured in lumen-hours.
Figure 1-1. Life-Cycle Assessment Impacts of the Lamps Analyzed Relative to Incandescent
Page 3
As shown in Figure 1-1, the plots representing LED and CFL technology fall well within the outer circle,
illustrating clearly that the incandescent lamp has the highest impact per unit lighting service of all the
lamps considered. This finding is not a function of the material content of a single lamp, as the
incandescent lamp has the lowest mass and is least complex lighting system. Rather, it represents the low
efficacy of this light source, and the resulting large quantities of energy required to produce light and
many replacements are required to span the (longer) rated life of an LED lamp or CFL. Generating the
higher amount of electric energy consumed per unit of light output causes substantial environmental
impacts and results in the incandescent lamp being the most environmentally harmful across all fifteen
impact measures.
While it has substantially lower impacts than incandescent, the compact fluorescent lamp is slightly more
harmful than the 2012 integrally ballasted LED lamp against all but one criterion – hazardous waste
landfill – where the manufacturing of the large aluminum heat sink used in the LED lamp causes the
impacts to be slightly greater for the LED lamp than for the CFL. The best performing light source is the
projected LED lamp in 2017, which takes into account several prospective improvements in LED
manufacturing, performance, and driver electronics.
Figure 1-2 presents the same findings shown in Figure 1-1, but the graph has been adjusted to remove the
incandescent lamp and provide the impacts relative (primarily) to the CFL.
Figure 1-2. Life-Cycle Assessment Impacts of the Lamps Analyzed Relative to CFL
Page 4
Overall, the prospective impacts of the improved LED lamp in 2017 are, like the others, significantly less
than the incandescent, and about 70% lower than the CFL and approximately 50% lower than the 2012
LED lamp, which reflects the best available technology today. The important finding from these graphs is
not necessarily the minor relative differences between the LED lamp and the CFL, but instead the very
significant reduction in environmental impacts that will result from replacing an incandescent lamp with a
more efficient product. Environmental impact reductions on the order of 3 to 10 times are possible across
the indicators through transitioning the market to these new, more efficacious light sources. Because of
the dominant role of energy consumption in driving the impacts, continued focus on efficacy targets, cost
reduction and market acceptance is appropriate. Furthermore, the greatest environmental impact after
energy in-use for the LED sources is the aluminum heat sink, which would be reduced in size as the
efficacy increases, and more of the input wattage is converted to useful lumens of light (instead of waste
heat). The heat sink is the main reason that the LED currently exceeds the CFL in the category of
hazardous waste to landfill, which is driven by the upstream energy and environment impacts from the
manufacturing of the aluminum from raw materials. Although end-of-life was evaluated in a conservative
way for this report, recycling efforts could also reduce the adverse impact of manufacturing the aluminum
heat sink. The potential to alleviate impacts through good design and end of life recovery was evaluated
in a letter published by Carnegie Mellon University (Hendrickson, 2010).
Underlying LED Technology Assumptions
In the literature reviewed for Part 1 of this study, one of the researchers had used the Ecoinvent database
entry for the LED when characterizing the packaged LEDs from a general illumination lamp. This entry is
for an indicator LED, and it is based on LED manufacturing technology from 2007, rather than the
equipment being used today. For the purposes of understanding how much LED technology has improved
or otherwise differs from the LED characterization in the present Ecoinvent database version 2.2, the
authors prepared a comparison of the environmental impacts associated with two representative LEDs,
one assumed by Ecoinvent, and the other reflecting newer technology. Due to the fact that the former
LED is a 5 millimeter indicator lamp and the latter a high-brightness LED used in general illumination
applications, the impacts need to be normalized for lighting service (i.e., lumen-hours) from each device.
The indicator lamp was found to have a light output of 4 lumens, while the high-brightness LED was
found to have a light output of 100 lumens (Radio-Electronics, 2012; Philips, 2012). The results show a
significant reduction in the environmental impacts on a per-lumen basis that have been achieved between
the 2007 Ecoinvent assessment and the 2011 technology that was assumed in this study. Overall, the
average reduction in impact is 94.5%. Thus, on a lumen output basis, it would appear that high-brightness
LEDs manufactured in 2011 are significantly less harmful for the environment than the 5mm indicator
LEDs that were produced in 2007.
This report represents the first publicly available LCA that includes a unit process for the LED
manufacturing specific to illumination applications. This process can be used for future investigations of
other lighting products based on LEDs and can be refined by the lighting community to represent new
processes as they become available. As one of the first public assessments of this type, the authors have
made several conservative assumptions:
• Recovery and recycling of materials – there is a lack of information in the public domain about
the extent to which materials used in the manufacturing of LEDs are reused and recycled. If these
materials are recovered, processed and then reused, this would reduce the per unit production
environmental impacts. However, this study assumes new materials or materials with the lowest
percentage recycled content are used at all stages of the LCA process, thus providing a
Page 5
conservative estimate of the impacts. To the extent that materials are recovered and recycled, the
environmental impacts will be less than those reported in this study.
• Transport and end-of-life – Information was limited on the transport and end-of-life phases of
LED, CFL and incandescent lamps. Working estimates were developed based on available data
and supplemented with stakeholder input to try and address all aspects of the life cycle.
• Wafer size – This report assumes a three-inch sapphire wafer substrate, although industry sources
indicate that larger wafers are rapidly being adopted. This assumption is also conservative to the
extent that improvements in this area also reduce the impact of LEDs in the next 5 years.
Page 6
2 Introduction
The U.S. Department of Energy (DOE) supports the market introduction of new energy efficient products
through several programs. The research described in this report falls within DOE’s Solid-State Lighting
(SSL) program and seeks to apply the internationally-recognized environmental assessment method called
Life Cycle Assessment (LCA) to the environmental impact of light emitting diodes (LEDs). LED-based
general illumination products have the potential to surpass many conventional lighting technologies in
terms of energy efficiency, lifetime, versatility, and color quality. According to a recent forecast, LED
lighting will represent 74 percent of U.S. general illumination lumen-hour sales by 2030, resulting in an
annual primary energy savings of 3.4 quads (DOE, 2012d).
An LCA is a scientific methodology that enables researchers to quantify the environmental and
sustainability impacts of a product across a range of categories for a product over its entire life cycle. An
LCA study can take on many forms, including, for example, analysis of different products to determine
their comparative impacts. LCA studies are publicly available on a wide range of products, including
supermarket shopping bags (EAUK, 2011), automobile tires (Continental, 1999), lithium-ion batteries
(Gaines, 2010) and lamps and luminaires (OSRAM, 2009).
Published earlier in 2012, Part 1 of this study identified gaps in the public literature associated with LED
manufacturing and use (DOE, 2012a). The authors reviewed existing LCA literature, focusing on the
energy consumed in manufacturing and use of the lamps studied. The report compares the life-cycle
energy consumption of an LED lamp to those of an incandescent lamp and a CFL based on the findings of
ten independent studies. The Part 1 report provides the following results:
1. A literature review of more than 25 LCA studies in this field.
2. A summary of the LCA process and methodology.
3. A meta-analysis based on findings of the ten most relevant studies and a functional unit of
20 million lumen-hours for incandescent, halogen, CFL and LED lamps.
Table 2-1 shows the ten studies that were used for the Part 1 analysis.
Page 7
Table 2-1. Key Publications Reviewed in DOE’s Part 1 Report (DOE, 2012a)
Publication Title Author Year
Lamp Types
GLS
CFL
LED
1. Life-cycle Analyses of Integral Compact
Fluorescent Lamps Versus Incandescent Lamps
Technical University of
Denmark
1991
X
X
2. Comparison Between Filament Lamps and
Compact Fluorescent Lamps
Rolf P. Pfeifer
1996
X
X
3. The Environmental Impact of Compact
Fluorescent Lamps and Incandescent Lamps for
Australian Conditions
University of Southern
Queensland
2006
X
X
4. Comparison of Life-Cycle Analyses of Compact
Fluorescent and Incandescent Lamps Based on Rated
Life of Compact Fluorescent Lamp
Rocky Mountain
Institute
2008
X
X
5. Energy Consumption in the Production of High-
Brightness Light-Emitting Diodes
Carnegie Mellon
University
2009
X1
6. Life-Cycle Assessment and Policy Implications of
Energy Efficient Lighting Technologies
Ian Quirk
2009
X
X
X
7. Life-cycle Assessment of Illuminants - A
Comparison of Light Bulbs, Compact Fluorescent
Lamps and LED Lamps
OSRAM, Siemens
Corporate Technology
2009
X
X
X
8. Life-cycle Assessment of Ultra-Efficient Lamps
Navigant Consulting
Europe, Ltd.
2009
X
X
X
9. Reducing Environmental Burdens of Solid-State
Lighting through End-of-Life Design
Carnegie Mellon
University
2010
X2
10. Life-cycle Energy Consumption of Solid-State
Lighting
Carnegie Mellon
University, Booz Allen
Hamilton
2010
X3
1. The Carnegie Mellon (2009) study only provides energy estimates for an LED package.
2. The Carnegie Mellon (2010) study only provides data on the bulk lamp materials of an LED lamp.
3. Data from this publication was provided from a poster presentation at the 2011 DOE SSL R&D Workshop.
The Part 1 report concluded that the life cycle energy consumption of LED lamps and CFLs are similar at
approximately 3,900 MJ per 20 million lumen-hours of lighting service as shown in Figure 2-1.
Incandescent lamps consume approximately four times more energy (approximately 15,100 MJ per 20
million lumen-hours). The authors also conclude that the use phase is the largest contributor to the energy
consumption, followed by manufacturing of the lamps and finally transportation (the last representing less
than 1% of total energy consumption). One key issue identified in the report is the high uncertainty
associated with the manufacturing process reflecting differences among studies in literature, which span a
range of 0.1% to 27% of the total energy consumption from manufacturing.
Page 8
Figure 2-1. Life-Cycle Energy of Incandescent Lamps, CFLs, and LED Lamps (DOE, 2012a)
The manufacturing process for packaged LEDs has only been analyzed in two sources of literature. The
first involves a simple unit process for LED’s used by the electronic industry for indicator lights
developed in 2007 (Ecoinvent 2012) and the second is an independent LCA performed by a manufacturer,
OSRAM (OSRAM 2009). Since each of these studies has its respective limitations, the focus of Part 2 is
exploring the LED manufacturing process in an attempt to address the high uncertainty in the literature.
This Part 2 report seeks also to evaluate the materials and processes that are hazardous to human health
and the environment involved in the manufacturing of LED based products. The results of this analysis
were then incorporated into a study of the wider life-cycle impacts of LED lamps and luminaires
(addressing residential and commercial products), relative to conventional light sources.
Page 9
3 Life-Cycle Assessment Methodology
An LCA is a scientific methodology that enables researchers to quantify the environmental and
sustainability impacts across a range of categories for a product over its entire life cycle. An LCA
characterizes and quantifies the inputs, outputs, and environmental impacts of a specific product or
system at each life-cycle stage (ISO, 2006). The general procedure for conducting a life-cycle analysis is
defined by the International Organization for Standards (ISO) 14000 series. The main phases of an LCA
according to ISO guidelines are goal, scope, and boundary definition; life-cycle inventory (LCI) analysis;
life-cycle impact assessment; and interpretation. The LCA is discussed in more detail in the Part 1 report
(DOE, 2012a).
3.1 International LCA Standards
LCA methods are scientifically grounded in a series of standards and technical specifications issued by
the ISO. A list of the current standards and reports included in this series is provided below, along with
the ISO’s brief descriptions of each document (note: some of the ISO descriptions make reference to ISO
standards that have subsequently been superseded by other standards). The DOE research project
conducting an LCA of LED lamps and luminaires compared to traditional light sources conforms to the
methodology and requirements of the current ISO standards and technical specifications.
• ISO 14040:2006. Environmental management – Life cycle assessment – Principles and
framework. ISO 14040:2006 describes the principles and framework for a LCA including:
definition of the goal and scope of the LCA, the LCI phase, the life cycle impact assessment
(LCIA) phase, the life cycle interpretation phase, reporting and critical review of the LCA,
limitations of the LCA, the relationship between the LCA phases, and conditions for use of value
choices and optional elements. ISO 14040:2006 covers LCA studies and LCI studies. It does not
describe the LCA technique in detail, nor does it specify methodologies for the individual phases
of the LCA.
• ISO 14044:2006. Environmental management – Life cycle assessment – Requirements and
Guidelines. ISO 14044:2006 specifies requirements and provides guidelines for LCA including:
definition of the goal and scope of the LCA, the LCI phase, the LCIA phase, the life cycle
interpretation phase, reporting and critical review of the LCA, limitations of the LCA,
relationship between the LCA phases, and conditions for use of value choices and optional
elements. ISO 14044:2006 covers both LCA and LCI studies. This standard supersedes and
replaces ISO 14041:1998, ISO 14042:2000 and ISO 14043:2000.
3.2 Brief Overview of an LCA
The four primary phases of an LCA process involve iterations of interpretation and revision. The diagram
below illustrates these key aspects of the process, and a brief description on each is presented below the
diagram. Each aspect of the process is discussed in more detail in the Part 1 report (DOE, 2012a).
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Figure 3-1. Key Aspects of an LCA Study (ISO 2006)
1. Goal & Scope Definition: section 4.2 ISO 14044:2006. The first phase of an LCA is to specify
the goal and scope of the study. The goal has four key aspects, including: (1) the intended
application of the study (e.g., marketing, product development, strategic planning); (2) the
purpose of the study (e.g., to be published or used internally); (3) the intended audience,
including shareholders, executives, consumers; and (4) use as a comparative analysis, whereby
the LCA results are used to compare with other products or materials.
2. Inventory Analysis: section 4.3 ISO 14044:2006. The second phase is characterized by the
compilation and quantification of inputs and outputs for a given product system through its life
cycle. The data collected and used in this phase includes all environmental and technical
quantities for all relevant unit processes within the system boundaries.
The final part of this phase is a data quality and processing stage, which requires the following
three actions to be completed: (1) data validation (an on-going process); (2) relating data to unit
processes and (3) relating data to the functional unit. This stage is necessary in order to complete
the next phase, calculating the impact for each unit process and the overall system.
3. Impact Assessment: section 4.4 ISO 14044:2006. This third phase identifies and evaluates the
magnitudes and relative importance of the environmental impacts arising from the inventory
analysis. The inputs and outputs are assigned to impact categories and their potential impacts are
quantified according to the characterization factors. Examples of the impact categories include:
resource depletion (energy, water, fossil fuels, chemicals, etc.), land use, greenhouse gas
emissions, and water pollution. According to ISO 14044, certain mandatory elements must be
included when conducting an LCA – such as the selection of relevant impact categories,
Goal and Scope
Definition
Inventory
Analysis
Impact
Assessment
Interpretation
LCA Framework
Source: ISO 14044:2006
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classification and characterization. Other elements are optional, such as normalizing the findings,
grouping them and/or applying a weighting of any sort.
Impact categories are chosen as the outputs from the study, for which environmental effects of the
analyzed system will be quantified. This selection of categories is driven at least in part by the
goal of the study, ensuring that the metrics for comparison are relevant to the objective.
4. Interpretation: In this final phase, the results are checked and evaluated to confirm that they are
consistent with the goal of the study. As shown in the diagram, the three other phases are all
connected to Interpretation, illustrating the point that this phase is a pivotal part of the process
and can lead to revisions in any point of the process.
The evaluation step is focused on enhancing the reliability of the study. This includes for example
a sensitivity check on the uncertainties around the data, assumptions, allocation methods and
calculations. It also includes a gap analysis or completeness check, to ensure there aren’t any
missing or incomplete areas that need to be analyzed in order to meet the goal and the scope of
the study. If no missing information is identified, then this should be noted in the report. Finally,
the evaluation step includes a consistency check to ensure that the methods and the goal are met,
including for example, data quality, system boundaries, data symmetry or time period, and so on.
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4 Goal and Scope
During the scope phase, the product or process under study is fully described, all assumptions are defined
and the methodology that will be used to assess the product system is presented. There are many factors
that must be taken into consideration in the scope phase, including the function of the product, the
functional unit, the system boundaries, the impact categories and assessment method, the data
requirements and assumptions, and the limitations of the analysis.
4.1 Goal Statement
The DOE is conducting a broad study to assess and compare the environmental impacts of general
illumination LED lamps and luminaires with conventional lamps and luminaires. Table 1 provides an
overview of the goal of the study consistent with the ISO standard (ISO, 2006).
Table 4-1. Summary of the Life-Cycle Assessment Goal for this Report
LCA Element
Summary for this Work
Intended Application
To compare the energy and environmental impact of LED lamps used in
general illumination applications with traditional lighting products.
Reasons for the Study
• To quantify the energy and environment impacts of LEDs.
• To address uncertainty in the existing body of literature and LCA
reports concerning LED manufacturing methods and assumptions.
Audience
Lighting designers, policy makers, researchers and technical experts
considering LED technology in general illumination applications.
Public Results
Results of this study will be freely available, published on the U.S. DOE
Solid State Lighting website: http://www1.eere.energy.gov/buildings/ssl/
4.2 Scope
The scope of this study is a comparison between the energy and environmental impacts of LED
technology used in general illumination applications and traditional light sources, namely incandescent
lamps and CFLs. For consistency with Part 1 of the work the functional unit has been established as 20
million lumen-hours of lighting service, which is approximately representative of total light output of a
Philips EnduraLED 12.5W lamp over its lifetime.
The diagram in Figure 4-1 depicts the system boundary and the five stages (Inputs, Manufacturing,
Transport, Use and End of Life) of the LCA analysis. All of these stages will be discussed and analyzed
for an integrated LED lamp in the context of this (Part 2) study. The red box highlights three unit
processes for the LCA that focus specifically on the manufacturing of LEDs. In general, the authors found
that this has not been reported in adequate detail in prior literature and thus represents an important area
for study and analysis.
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Figure 4-1. System boundary of the Life Cycle Assessment of this Study (Part 2)
As shown in the figure above, the impact inventories are broken down into the five life cycle stages,
which include (1) inputs / raw materials, (2) manufacturing, (3) transportation to point of sale, (4) use of
the product and (5) end-of-life disposal / recycling. These five stages of an LCA are briefly described
below.
1. Raw Material Production - many products are made up of multiple components, and lamps are
no exception. This first stage of the life cycle accounts for the emissions and resource usage
associated with the production and transport of the various raw materials and intermediate
products that are inputs to the final product. Estimating impacts of producing and transporting
material inputs prior to their reaching the final manufacturer relies on Ecoinvent (version 2.2), an
extensive database developed and maintained by the Swiss Center for Life Cycle Inventories.1
2. Manufacturing - the manufacturing phase takes all of the raw materials defined above, as
delivered to the point of production, and accounts for the energies used and emissions associated
with fabricating the lamp. In this analysis all of the major component parts are depicted in the
figure to highlight these component parts.
3. Distribution - the distribution phase covers the transportation of the product from its point of
manufacture to its point of installation and use. There might be a tendency when thinking about
an LCA to believe that a detailed transport model will be required. However, for many products,
transport and distribution form a small part of the overall environmental footprint. Impacts from
distribution tend to be much more significant if the product needs to be refrigerated during the
distribution stage of the process, which isn’t the case for lighting products.
4. Use/Consumption - the use/consumption phase of a product is usually straightforward to
describe, though it is important that a consistent basis is chosen to enable fair comparisons
between different products. In order to be consistent with the Part 1 study, the use phase is based
around the lighting service associated with each lamp type.
1 Swiss Center for Life Cycle Inventories, http://www.ecoinvent.org/
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5. End-of-Life - the final stage of a life cycle is the end-of-life stage which reflects what happens
to the lighting products when they have stopped working and are no longer required. The end-of-
life phase takes into account any other integral parts of a product’s life-cycle, most notably the
box and packaging. There is also the question of whether to give a process credit for any end-of-
life recycling which could, for example, reduce reliance on raw materials. However, if a
particular process assumes a reduced impact due to the incorporation of recycled materials or the
use of recycling processes in the waste stream, to add process credits back into the impact
calculation on top of those reduced impacts might constitute double-counting. For this study
therefore, any benefits associated with recycling have been taken into account by using recycling
processes in the waste stream.
4.3 Bounding the Scope of the Study
Due to the fact that there are many different materials, methods and technologies available for producing
packaged white light LEDs, some analytical decisions were made to ensure the scope of this LCA is
manageable and representative of LEDs used for general illumination. These decisions were taken with
the objective of ensuring that the material and/or the process selected is common practice in the market or
is representative of the methods that will be adopted in the future. In this way, the findings from this LCA
study are intended to be representative of the LEDs commonly used in general illumination. Future
innovations such as improved yield rates and larger wafer sizes will reduce the waste and environmental
impact associated with manufacturing each packaged LED. In this way, the conclusions from this analysis
represent a conservative estimate of the impacts.
Given the many different approaches and technologies for creating white-light LEDs, several decisions
are needed in order to create a manageable scope for this LCA study. These decisions relate to (1) the
substrate used in manufacturing, (2) the type of LED produced and (3) the methodology used to create
white light.
4.3.1 Substrate
Gallium nitride (GaN) LEDs, which are commonly used as the light source for white light LEDs, can be
grown on a range of different substrates, including sapphire, silicon carbide (SiC), bulk GaN, silicon,
germanium, borosilicate glass, poly-crystal aluminum nitride (AlN), zinc oxide and diamond.2 Of these,
the one most commonly used for growing GaN LEDs is sapphire. In fact, it is estimated that more than 80
percent of LEDs are built on a sapphire substrate (Compound Semiconductor, 2011). Indicative of this
majority share in the market, the recent surge in demand for LEDs as the television industry converted
liquid crystal display (LCD) flat-screen back-lighting technology from cold-cathode fluorescent to white-
light LED, the market experienced an acute shortage in sapphire wafers (Yole, 2011).
Within the substrate technologies, the general trend is toward larger wafer size in LED manufacturing. It
is understood, from years of experience working with semiconductors that moving to larger wafer sizes
will not only reduce manufacturing costs but will also improve yield. In moving to the larger substrate
wafers, manufacturers get better results through more efficient use of the epitaxy reactor and fewer edge-
related defects. However, due to deposition stresses experienced by the wafers, larger diameter wafers
2 Yole Développement, personal communication, November 2011.
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have to be thicker than smaller diameter wafers. The typical thickness of a 2” (51 mm) wafer is 425 μm
compared to a 6” (150 mm) wafer which is typically 625 μm thick (Dadgar, 2006) – an increase of 47%.
However, the process improvements in the reactor more than off-set the higher substrate cost, so the
overall effect is a net reduction in per unit cost (LED Magazine, 2010).
The manufacturing shift to larger wafers will reduce the unusable edge area on each wafer that has to be
excluded from further processing, and it enables more effective (and less wasteful) use of metal organics
and hydrides in the metalorganic chemical vapor deposition (MOCVD) process. Consider the output data
from the Aixtron 2800G4 HT, one of the popular MOCVD reactors used by the LED industry. The
comparison is illustrated in the figure below, which shows one of the wafer trays, loaded with 42 two inch
wafers on the left and 6 six inch wafers on the right.
Figure 4-2. Comparison of MOCVD Reactor Tray, 2” versus 6” wafers
The table below provides the data behind the rationale for this gradual shift toward larger wafer sizes. In
this table, the total wafer area that can be loaded into the machine is calculated, and then in a second
calculation, the un-usable rim area is deducted from the usable area, giving the anticipated number of
LED chips that would result from using the larger wafer size. For example, the surface area of a six inch
wafer is nine times that of a two inch wafer, but it can yield between ten and twelve times as many chips
as a two inch. Thus, industry experience with wafers for LED production has shown the yield multiplier is
greater than the surface area multiplier.
Table 4-2. Wafer Sizes and the Corresponding Surface Area and Yield of LED Chips
Wafer Size Surface Area Multiplier
Yield Multiplier
(i.e., Number of LED Chips)
2 inch (51 mm)
S
N
4 inch (100 mm)
4∙S
4.5∙N to 5∙N
6 inch (150 mm)
9∙S
10∙N to 12∙N
8 inch (200 mm)
16∙S
20∙N to 22∙N
12 inch (300mm)
36∙S
45∙N to 50∙N
Source: Compound Semiconductor, 5 December 2011.
According to a study by Aixtron, a German manufacturer who produces MOCVD reactors, the overall
result is a 52% increase in the usable wafer area that can be gained simply by moving from two inch
diameter to the larger six inch wafers. These significant gains in LED manufacturing reflect the same
savings that the silicon industry experienced as it scaled microchip production to larger and larger wafer
Page 16
diameters. In addition, the cost associated with retooling the MOCVD reactors to move from two inch to
four or six inch, as shown by the illustration above, is not a high – the equipment has been designed to be
flexible and thereby accommodate the anticipated transition to larger substrate diameters.
The following diagram prepared by Yole Développement depicts the forecasted trend in sapphire
substrate diameters for the coming years (Compound Semiconductor, 2011). Small two inch (51 mm)
diameter wafers are expected to be 1% by 2015, while six inch wafers (150 mm) are projected to be more
than half the market in that year.
Figure 4-3. Trends in Diameter of Sapphire Substrates for LED Manufacturing
Source: Yole Développement, 2011 as published in Compound Semiconductor, December 2011.
Although Yole Développement projects a trend in the market toward larger wafer sizes, for the purposes
of this study, we focused on three inch sapphire wafers for two main reasons. First, LED manufacturing
with smaller diameter wafers is better known and more widespread in 2012, thus it is easier to gather data
and input from experts familiar with the common practice. Second, the environmental impact per unit of
LED produced (i.e., LED yield) at a smaller diameter will be greater than the impact experienced at the
larger wafer sizes, which will be more prevalent in the future. Thus, by quantifying the LCA impacts of a
three inch wafer in 2012, we know that these impacts represent an upper limit of environmental impacts
now, and future impacts will be less than those in 2012 as the industry migrates to larger wafer sizes.
4.3.2 LED Type
Numerous chemistries have been developed for commercially available LEDs based around phosphides
and nitrides. The light emission from an LED depends on the p-n junction and the chemicals (e.g.,
gallium, arsenic) that are doped into the layers of the LED and used to construct the active layer. These
different materials emit light at discrete wavelengths in the electromagnetic spectrum, spanning from the
infrared through to the ultraviolet, and including visible light. The exact choice of the semiconductor
material used in the LED helps to determine the color of the light emission.
The following table presents some of the common chemistries used today in producing the colored LEDs
listed in the first column.
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Table 4-3. Summary of LED Colors and Common Chemistries
Color
Wavelength
Materials
Infra-Red
850-940 nm
Gallium arsenide, Aluminum gallium arsenide
Red 630-660 nm
Aluminum gallium arsenide, Gallium arsenide phosphide, Gallium
phosphide
Amber
605-620 nm
Gallium arsenide phosphide, Aluminum gallium indium phosphide
Yellow 585-595 nm
Aluminum gallium phosphide, Gallium arsenide phosphide, Gallium
phosphide
Green
550-570 nm
Aluminum gallium phosphide, Gallium nitride
Blue 430-505 nm
Indium gallium nitride, Gallium nitride, Silicon carbide, Sapphire,
Zinc selenide
Ultraviolet
370-400 nm
Indium gallium nitride, Aluminum gallium nitride
LEDs are discrete wavelength emitters, meaning they produce light in a narrow bandwidth based on the
chemistry of their underlying p-n junction. White light, on the other hand, consists of many different
wavelengths (colors) of light which, when blended together, are perceived by the human eye as being
“white”. As discussed in the next section of this report, there are several different methods for producing
white light from LEDs, however it is recognized that the vast majority of white light LEDs manufactured
today are based on the combination of a blue-emitting gallium nitride (GaN) or indium gallium nitride
(InGaN) LED source used in combination with a yellow-emitting cerium-doped yttrium aluminum garnet
(Ce3+ YAG) phosphor (LFW, 2011).
For general illumination applications, lamp and luminaire manufacturers have some flexibility when
designing the light producing portion of their equipment. This can include, for example, a cluster of many
low-power LEDs which have a low light output individually, but when grouped together produce light
levels sufficient for general illumination applications. This may also include devices that incorporate a
small number of jumbo LEDs or multi-chip arrays, each emitting thousands of lumens. Although there is
potential to use any of these approaches in general illumination applications, it is expected that the high
power and jumbo LEDs will ultimately dominate the lighting market as these configurations can benefit
from better optics, optimized thermal control and fewer components. The following table presents some
of the electrical characteristics and applications for the different classes of white light LEDs.
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Table 4-4. White Light LED Package Segmentation
Item Low Power LED Mid Power LED High Power LED
Jumbo LEDs &
Multichip Arrays
Driving current
Bias voltage
Power
Die size
Package flux
5 to 20 mA
2.9 to 3.5 V
<100 mW
200 to 360 μm
4 to 15 lm
50 to 150 mA
2.9 to 3.5 V
<500 mW
380 to 600 μm
12 to 65 lm
≥ 350 mA
2.9 to 3.5 V
1 to 3 W
500 to 1500 μm
70 to 120 lm
≥ 350 mA (up to 6.5)
3 to 3.5 V
1 to 3 W
>4 mm2 (up to 36 mm2)
up to 6000 lm
Packaging
Encapsulated LED,
SMD top & side
SMD top & side
Power package
Power package; arrays
Typical
Applications
Mobile phones –
keypad and display
Small LCD
backlight
Signs, large displays
TV backlighting
Automobile
headlights
Large displays
General lighting
Automobile
headlights
Projection
General lighting
General lighting
Projection
Automobile headlights
Although it is possible to have general illumination devices developed from low power LEDs, devices in
2012 are more commonly designed around mid-power, high-power and jumbo-LEDs. For the purposes of
this study, we will therefore focus our LCA assessment on the 1-watt LED devices which can be
commonly found in multiple-LED configurations in lamps and luminaires for general illumination
applications.
4.3.3 White Light
As discussed, LEDs are discrete semiconductors that produce a narrow-band emission which, depending
on the chemistry, can emit energy in the ultraviolet (UV), visible, or infrared regions of the
electromagnetic wavelength spectrum. To produce white light for general illumination applications, either
the narrow spectral emission from LEDs must be converted into white light or two (or more) discrete
LED light outputs must be mixed together.
White light LED devices are generally based on one of three approaches for producing a distribution of
visible wavelengths that are perceived as “white light”. These are: (a) phosphor-conversion LEDs (pc-
LEDs); (b) discrete color-mixing; or (c) a hybrid method, as shown in the figure below (DOE, 2012b).
Phosphor-conversion LEDs create white light by blending a portion of the blue light emitted directly from
the chip with light emission down-converted by a phosphor from the blue part of the spectrum to other
colors. Discrete color-mixing, on the other hand, starts with discrete colored sources and uses color
mixing optics to blend together the light output to create white light emission. The hybrid method uses a
combination of pcLEDs and discrete-colored LEDs to create the desired light output. Two other methods
of producing white light emission that are not discussed here include (1) an approach based on
homoepitaxially grown zinc selenide (ZnSe) on a ZnSe substrate that emits blue light from the active
region and yellow light from the substrate (Chang, 2007) and (2) quantum dots that achieve the light
wavelength down shift within the visible spectrum (Salisbury, 2005).
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Figure 4-4. General Types of White Light Emitting Diode (LED) Devices
Source: DOE, 2012b. Solid-State Lighting Research and Development: Multi-Year Program Plan.
The majority of white light LEDs in production today are phosphor converting LEDs based on gallium-
nitride, emitting blue light between 450-470 nm (DOE, 2011). This blue light excites a yellow phosphor,
usually made of Ce3+:YAG crystals that have been converted into a powder. As the LED chip emits blue
light, some is emitted directly through the phosphor and some is converted by the phosphor to a broad
spectrum centered around 580 nm (yellow) by the Ce3+:YAG. This yellow light stimulates the red and
green receptors in the human eye, resulting in a mix that gives the appearance of white light.
The pcLED approach, developed by Nichia, was first marketed by them in 1996 as a white-light LED.
This approach has since been adopted by numerous other manufacturers as a method for producing white
light, and constitutes the most common approach today. Depending on the phosphors used, and whether
those phosphors are mounted in the LED package or located remotely (e.g., such as you find with the
Philips EnduraLED lamp), there can be improvements made in the light quality and efficiency of the
phosphor. While improvements in phosphor technology will yield benefits to the performance overall, the
losses associated with absorbing blue light and down-converting it to other wavelengths such as green,
yellow and red, establish a limit to the ultimate efficiency of the LED system. These losses are called
“Stoke’s loss” and are associated with any phosphor-based down-conversion of light, including the
process by which fluorescent tubes emit white light.
Discrete color-mixing of LED light emissions avoids the need for phosphors, and therefore promises to
offer the highest efficacy LED device. In color-mixing, LED devices mix discrete light emissions from
two or more LED chips which are blended together to produce white light. The principal advantage of the
color-mixing method is that it does not involve phosphors, thereby eliminating phosphor conversion
losses in the production of white light. This approach is not without its challenges however, such as multi-
Page 20
chip mounting and potentially sophisticated optics and electronics for blending and maintaining the
balance of colored light emissions.
The third method shown in the figure is a hybrid approach that combines pc-LEDs and colored-light
emission LEDs into the same luminaire, producing the desired white light output. For example, some
manufacturers are combining pc-LEDs with high (cool-white) correlated color temperature3 (CCT)
emission with several yellow and red-light emitting LEDs to create a lower (warm-white) CCT. In this
example, the discrete color-emitting LEDs are used to change cool-white CCT to a warm-white CCT. The
efficacy of this hybrid system will be higher than a pc-LED system, but lower than a color-mixing
system, and will be proportional to the relative share of light output of the LEDs used in the hybrid
system.
The most common approach used in white light LEDs today for general illumination applications are the
blue-light emitting phosphor converting LEDs. These LEDs can have a range of resultant CCT values,
depending on the types and amounts of phosphor used. For lamps that use remote phosphors, the LEDs
will emit a deep blue light which is then converted by the remote phosphor into white light. For the
purposes of this study, we are focusing on this system – namely blue light LEDs that are pumping a
remote phosphor and creating a warm white light emission.
4.3.4 The Representative LED for the Manufacturing Unit Processes
Taking into account the discussion in this chapter, the conclusion reached is that this LCA study will
focus on the following archetype general illumination LED lamp system:
• Three-inch sapphire wafer substrate
• Indium-Gallium Nitride grown on sapphire substrate
• High brightness LED packages (i.e., greater than 0.5 watt / package)
• Deep-blue LEDs (which are pumping a remote phosphor)
Overall, the type of LED which is meant to be characterized by this study then would be something akin
to the following commercially available high brightness products such as: Cree’s XLamp; Osram’s
Dragon; Philips’ Luxeon Rebel or Seoul Semiconductor’s P4. The decision to use a three-inch wafer is
intended to make the LCA conservative in assessing the technology, although it is known that the larger
wafers are being adopted quickly as shown in Figure 4-3.
4.4 Limitations of the Study
The content of the literature and technical information assessed for this study was focused as much as
possible on LED manufacturing and lamp parts / assembly. As discussed in the next section, matches
between the material and the process in the Ecoinvent database were imperfect in some instances. The
3 The CCT is the temperature of a blackbody that best matches the color of a given light source. It describes the
color appearance of the source, measured on the Kelvin (K) scale. Lamps with a CCT below 3500 K appear more
yellowish-white (i.e., warm) in color. Lamps at or above 4000 K appear bluish-white (i.e., cool) in color. For
additional information, see the DOE fact sheet “LED Color Characteristics” (www.ssl.energy.gov/factsheets.html).
Page 21
study investigators chose the best appropriate match, and in one instance adjusted one of the key impact
parameters to account for a more energy intensive version of a similar material.
There are some gaps in relation to the life cycle assessment which have been identified:
• Emissions during LED manufacturing stage - it should be noted that direct emissions from the
manufacturing process were not included in this analysis, due to lack of available data. The
facilities where LEDs are manufactured operate in ‘clean room’ environments and use reactors to
create the LED die. These reactors have some recovery systems that are able to reuse materials
and others that allow harmless gases like nitrogen to vent into the atmosphere.
• Recovery and recycling of materials – there is a lack of information in the public domain about
the extent to which materials used in the manufacturing of LEDs are reused and recycled. If these
materials are recovered, processed and then reused, this would reduce the per unit production
environmental impacts. However, this study assumes new materials or materials with the lowest
percentage recycled content are used at all stages of the LCA process, thus providing a
conservative estimate of the impacts. To the extent that materials are recovered and recycled, the
environmental impacts will be less than those reported in this study.
• Transport and end of life – information on the transport and end of life phases of LED, CFL and
incandescent lamps was limited. Working estimates were developed based on available data and
supplemented with stakeholder input in an attempt to address all aspects of the life cycle.
4.5 Critical Review
In order to ensure the results of this work are accurate, a formal review process for the manufacturing unit
process was initiated early in the study. In the expert interviews stage, manufacturers and researchers
were invited to review the draft flow diagram for the manufacture of LEDs, and to comment on the
various inputs and steps in that process. These comments provided corrections as well as new data to
improve the accuracy of the process description. The final study has been reviewed in a similar way by a
group of reviewers broader than the initial review team, but inclusive of the same group of manufacturers
and researchers.
The diagram in Figure 4-5 depicts the analytical process that was followed for the manufacturing unit
process part of the study, and identifies the two steps in the process where external expertise was
requested. These occurred at the “Expert Interviews” stage where the draft process flow diagram was
circulated with experts for review and at the “Expert Review” stage where the findings of this study
compiled in a report form were again circulated for review and comment.
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Figure 4-5. Flow of Data Gathering and Analysis for this Research Project
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5 Life Cycle Inventory Analysis
This inventory of materials and processes developed for LED, CFL and incandescent lamps is drawn from
the work shared by Yole Développement and System Plus Consulting, Navigant Consulting Europe’s
report on a life-cycle assessment of ultra-efficient lamps, summary data from Osram Optoelectronic’s
2009 life-cycle assessment of an LED lamp, and various industry experts and researchers who provided
comment and input on the draft analysis. The quantification of the life-cycle impacts is based on the
Ecoinvent database (version 2.2). To address the large error bars associated with LED manufacturing
which was identified in DOE’s literature summary (DOE, 2012a), the focus of this life cycle inventory
will include this specific area.
5.1 Inputs
To quantify the environmental impacts of the incandescent, CFL and LED lamps, the authors used the
Ecoinvent life cycle impact assessment database version 2.2, from the Swiss Centre for Life Cycle
Inventories (http://www.ecoinvent.org). This database contains environmental impact data on over 4000
manufacturing or related processes, such as the impacts associated with the production of a kilogram of
cast aluminum from bauxite or the transportation by truck of one ton of material for one kilometer. For
each material and process in the database, there are estimates of the environmental impact for over 250
standard environmental indicators. For example, the database estimates that the global warming potential
impact associated with one kilogram of cast aluminum is 3.0614 kilograms of carbon dioxide equivalents.
In this chapter, there are a series of tables presented which provide detail on the inventories of materials
and processes associated with LED manufacturing and then with each of the mains-voltage general
illumination lamps studied. These tables give detail on the materials and processes that were selected
from Ecoinvent and used to model those materials and processes. Some of the Ecoinvent materials and
processes are very close matches to the ones used in the lamps while others are approximations. The
relative significance of these approximations becomes clear when the results are reviewed in Chapter 6,
and the more critical materials and processes are investigated in the sensitivity analysis presented in
Appendix A of this report.
Each of the three finished lamps analyzed in this study is different, having different levels of power
consumption and operating life. In order to make a fair comparison between the lamp technologies, it
becomes necessary to compare their relative performance over a comparable time period and using a
common metric. To achieve this, all of the impacts calculated for the three lamps are compared on a
normalized basis of lighting service delivered during the analytical time period. The quantity of light
produced over that time period is reported in lumen-hours of lighting service and then used to normalize
the estimated impacts.
Although the three lamps were chosen because they have approximately equal instantaneous light output,
it should be noted that over the lifetime of each lamp, the total lighting service is different. For instance,
due to the large disparity between the incandescent lamp and the LED lamp, the incandescent lamp must
take into account multiple lamp changes (and thus multiples of lamp-related impacts are compounded in
the analysis). Ultimately, all of the analysis culminates in a measurement of impacts in megalumen-hours
(Mlm-hr) over the full “use” stage of the LCA. For example, the final results for global warming potential
will be presented in units of kilograms of CO2-equivalent per Mlm-hr.
In addition to considering the impacts associated with an LED lamp in 2012, this study also projects the
impacts of the LED lamp in 2017. The impacts of the future LED lamp are expected to be lower due to
Page 24
the fact that LED performance and drivers will continue to improve and materials and components used in
the lamp can be reduced over time. Details relating to the assumptions behind the LED lamp in 2017 are
provided in this chapter.
The following table provides the performance parameters used as inputs to the three lamps analyzed and
the projected performance of an LED lamp in 2017. The second row from the bottom of the table
calculates the “total lifetime light output”. This parameter represents the cumulative light output measured
over the entire service life of the lamp, and is measured in megalumen-hours of light. The total light
output for the 2012 LED lamp, 20.3 Mlm-hr represents the functional unit from DOE’s Part 1 study and is
used in this analysis as a normalizing factor to adjust the impacts for equivalency. The scalar shown in the
bottom row of the table is calculated from the ratios of the lighting service output relative to the 2012
LED lamp.
Table 5-1. Performance Parameters for Lamps Considered in this Analysis
Characteristics Incandescent CFL
LED lamp –
2012
LED lamp –
2017
Power Consumption
60 watts
15 watts
12.5 watts
6.1 watts
Lumen Output
900 lumens
825 lumens
812 lumens
824 lumens
Efficacy
15 lm/W
55 lm/W
65 lm/W
134 lm/W
Lamp Lifetime
1500 hours
8000 hours
25,000 hours
40,000 hours
Total Lifetime Light
Output
1.35 Mlm-hr
6.6 Mlm-hr
20.3 Mlm-hr*
33.0 Mlm-hr
Impacts Scalar
15.04
3.08
1.00
0.61
* In Part 1 of DOE’s study (Review of the Lifecycle Energy Consumption of Incandescent, Compact Fluorescent and
LED Lamps), 20 megalumen-hours was selected as the functional unit for comparison of the energy use. In this
study (Part 2), we use the same functional unit as a normalizing scalar to ensure the impacts are comparable.
5.2 LED Manufacturing
LED manufacturing is a very complex and highly technical process and very few companies in the world
operate across all segments of the value chain. In an effort to simplify the process for producing a
packaged LED and to better align with the areas of specialization and expertise that exist in the industry,
we have broken down the value chain for LED manufacturing into three large segments – (1) substrate
production, (2) LED die fabrication and (3) packaged LED assembly. The flow diagram in Figure 5-1
summarizes these stages and the major steps contained within each stage. It should be noted that direct
emissions from the manufacturing process were not included in this analysis, due to lack of available data.
Page 25
Figure 5-1. Three Major Stages of Packaged LED Manufacturing
Following this structure, this chapter is divided into three sections, each discussing and describing these
stages of LED manufacturing.
5.2.1 Substrate Production
This stage is focused on preparing polished, cleaned sapphire wafers to use in an MOCVD reactor for
LED die fabrication. Wafer manufacturing starts with the growth of large sapphire crystal boules. To
produce these boules, a large amount of aluminum oxide is melted down and a seed crystal is introduced
to the molten solution. This seed crystal is then pulled slowly out of the solution, and because crystal
growth occurs uniformly in all directions, the cross section of the resulting crystal is circular. The
diameter of the crystal is a function of the melt temperature, the speed of rotation and the speed at which
the seed holder is pulled from the melt. The resulting boule must then be ground down to obtain the
desired diameter before it is sliced into wafers, polished and cleaned for LED fabrication.
The table on the following page provides the main processing steps involved in the production of sapphire
wafers, starting with the growth of sapphire boules and ending with finished, cleaned wafers. A brief
description of each step is provided in the table, along with an indication of the resources consumed in the
process, including both energy and material. The estimates provided in this table were kindly provided by
Yole Développement and System Plus Consulting for the purposes of assisting with this LCA study.
Page 26
Table 5-2. Steps Associated with Sapphire Wafer Substrate Manufacture
Processing
Step
Picture
Description
Inputs
Boule growth
in reactor
Using the Czochralski method to
melt aluminum oxide (Al2O3)
and grow a large sapphire
crystal boule
Energy: 15.51 kWh/wafer
Alumina: 16.61 gm/wafer
Water: 100 liters/wafer
Core
fabrication
Using diamond tooling, drill the
sapphire boule to create the
sapphire cores in the appropriate
diameters
Energy: 1.35 kWh/wafer
Wafer slicing
Slicing the cores into thin wafers
using a diamond internal
diameter saw with deionized
cooling water
Energy: 1.24 kWh/wafer
Water: 2 liters/wafer
Lapping and
beveling
Rough-cut wafers are treated to
remove saw marks and other
defects on both sides; also thins
the wafer and relieves stresses
accumulated from slicing; uses a
diamond slurry, 6μm
Energy: 0.09 kWh/wafer
Slurry: 430 gm/wafer
Water: 0.67 liters/wafer
Polishing and
Chemical-
mechanical
planarization
Wafers are subjected to 2-3
polishing treatments using
progressively finer slurry of
polycrystaline diamond (3μm -
1μm); removes irregularities
making wafer flat (i.e., planar)
Energy: 0.06 kWh/wafer
Slurry: 400 gm/wafer
Water: 0.67 liters/wafer
Geometry and
optical
inspection
Inspection to identify geometric
or optical defects that may limit
yield (e.g., surface pits or micro-
cracks)
N/A
Final cleaning
Cleaning to remove trace metals,
residues and particles. Uses
NH4OH, followed by dilute HF
acid, followed by a deionized
water rinse. The second clean
consists of HCl and H2O2
followed by a deionized water
rinse.
Energy: 0.001 kWh/wafer
Cleaner: 3.50 liters/wafer
Water: 2 liters/wafer
Source: Yole Développement and System Plus Consulting for quantities of process inputs.
As a quality assurance check on the mass of Alumina consumed to produce one wafer, a simple mass
calculation can be performed that takes into account the finished product and quantities of material lost
through processing from the raw crystal. Given that a three inch wafer diameter is 7.62 cm (radius [r] =
diameter/2 = 3.81 cm), the thickness (t) of the wafer is 0.033 cm and the density (ρ) of sapphire is
Page 27
3.98 g/cm3, the mass of the finished three inch wafer is m=r2∙π∙t∙ρ = 6.0 grams. Taking into account
sawing and polishing losses per wafer which are approximately 85% of the finished wafer, the mass of
sapphire core necessary to produce one finished 6.0 gram wafer would be 11.1 grams. A further 40% of
the original boule is lost when the sapphire cores are cut and approximately 5% of the Alumina remains in
the crystal-growing chamber. Taking these further adjustments into account, the 11.1 grams of sapphire
core scales to a raw material consumption to 16.3 grams per finished 6.0 gram wafer. The estimated
consumption of Alumina (Al2O3) per finished three-inch wafer was given in Yole Développement’s data
as 16.6 grams, therefore this estimate seems accurate.
Combining all of the materials and impacts quantified in the table above, the quantity of materials used in
producing cleaned, polished sapphire wafers for GaN LED fabrication are shown in the table below. This
table provides both the quantity consumed per wafer both in terms of volume and in terms of mass. The
right two columns provide the unique ID and description of the Ecoinvent database record to which it is
matched.
Table 5-3. Energy and Material Consumption for Three-Inch Sapphire Wafer Manufacturing
Stage Material Used
Amount
Eco-ID Ecoinvent Description
Volume per
wafer
Mass per wafer
Material
Alumina (Al2O3)
16.6 g/wafer
16.6 g/wafer
244
aluminum oxide, at plant
Material
Cleaning Chemical
(alkali detergent)
3.5 liters/wafer
3.5 kg/wafer
5902
ethoxylated alcohols (AE7),
petrochemical, at plant
Production
Energy Consumption
18.3 kWh/wafer
18.3 kWh/wafer
6693
electricity mix in China
Material
Diamond Slurry
830.0 g/wafer
0.83 kg/wafer
1997
zeolite, slurry, 50% in H2O,
at plant (adjusted)
Material
Water
105.3
liters/wafer
105.3 kg/wafer
7237
water, ultrapure, at plant
To represent the diamond slurry used in manufacturing, the closest match in the Ecoinvent database is
zeolite slurry, however there are two important differences. First, the embodied energy in diamonds is
greater than that of zeolite, and second the concentration of diamond abrasive in the slurry is lower than
the 50% level associated with the zeolite slurry. Due to these differences, and to make sure that this stage
of the LCA did not underestimate impacts, the authors increased the zeolite slurry energy impacts by a
factor of ten to represent the higher energy consumed manufacturing the diamonds. Overall, this
adjustment resulted in a 15% increase in the GHG emissions associated with the manufacturing of a
packaged LED, but constituted less than one-tenth of one percent of GHG emissions over the life cycle of
the 2012 LED lamp (i.e., including the balance of system (i.e., driver, housing, heat sink) as well as other
stages of the LCA including energy in use, transport and disposal).
5.2.2 LED Die Fabrication
In this section, the steps associated with fabricating LED die are described, with estimates of the
associated energy and materials consumed in these manufacturing steps. The LED die fabrication process
is subdivided into epitaxial growth and other front-end processes.
Page 28
In the epitaxial growth phase, the substrate is mounted in an metal organic chemical vapor deposition
(MOCVD) reactor and experiences a heating stage, followed by the deposition of the nucleation layer, the
n-type layer, the active layers (multi-quantum well) and finally the p-type layer. At the end of this phase,
the wafer is referred to as an LED epitaxial wafer.
The nucleation layer is critical because crystalline or contaminate defects will have a detrimental effect on
the yield from the wafer, so it is imperative that the sapphire layer is ultra-pure. This is a layer of sapphire
that is grown on the raw sapphire wafer through an epitaxial growth process. The layer is very thin, just
3% or less of the wafer thickness, but it is a critical step in the fabrication process.
Table 5-4. Steps Associated with Gallium Nitride Epitaxy
Processing Step
Description
Inputs
Bake out
Nitridation of the sapphire substrate at high
temperature in a hydrogen and ammonia
atmosphere.
8.75 kWh/wafer
0.06 m3 H2 / wafer
0.02 kg NH3 / wafer
Nucleation layer
The wafer is then lowered in temperature to
550°C to grow the nucleation layer.
4.74 kWh/wafer
Temperature ramp
The reactor chamber is heated to a very high
temperature (1200°C) under reduced ammonia
pressure to stabilize the nucleation layer.
1.46 kWh/wafer
0.02 kg NH3 / wafer
Buffer + N layer
(3.84µm)
The temperature is dropped to approximately
550°C to grow the buffer layer. This is a thin
amorphous film of gallium, just 50 to 100
atoms thick grown directly on the wafer. The
wafer is then heated up until the gallium forms
a smooth, mirror-like layer of gallium nitride.
Next, a layer of negatively doped gallium
nitride is deposited, with silane (i.e., silicon
tetrahydride, SiH4) as the electron-donating
dopant.
9.77 kWh/wafer
1.38 grams TMGa4 / wafer
0.42 kg NH3 / wafer
1.54 m3 H2 / wafer
1.54 m3 N2 / wafer
0.06 g SiH4 / wafer
Active layer MQW
(60nm)
The temperature is dropped from 1,200°C to
750-850°C to grow an indium gallium nitride
quantum well. This will include approximately
20 angstroms of InGaN and 100 angstroms of
GaN. This process is repeated to grow several
wells.
4.74 kWh/wafer
0.03 grams TMGa / wafer
0.01 kg NH3 / wafer
0.01 m3 H2 / wafer
0.01 m3 N2 / wafer
0.01 g TMIn
5
/ wafer
4 TMGa = trimethylgallium
5 TMIn = trimethylindium
Page 29
Processing Step
Description
Inputs
P layer (170nm)
After growing the last combination of
InGaN+GaN, the wafer is heated back up and a
confining layer of positively doped aluminum
gallium nitride (AlGaN) is deposited. The
positively doped layer confines the charge
carriers in the active layer.
3.28 kWh/wafer
0.06 grams TMGa / wafer
0.02 kg NH3 / wafer
0.06 m3 H2 / wafer
0.06 m3 N2 / wafer
0.00 g TMAl6 / wafer
Source: Yole Développement and System Plus Consulting for quantities of process inputs.
Taking the LED epitaxial wafer, a series of steps are followed which are working toward making the
device and preparing it for packaging. Following inspection, the wafer is subjected to masking /
lithography, followed by etching and then establishing metallization / contacts on the LED. These process
steps create the LED mesa-structure, and results in visible LED dies on the wafer. Once these are
developed, the substrate is separated from the LED dies, and they are then cut (i.e., die singulation) and
tested/ binned according to their performance. At the end of this stage, the LED dies are ready to be
packaged.
6 TMAl = trimethylaluminum
Page 30
Table 5-5. Post-Epitaxy Steps Associated with LED Die Fabrication
Processing
Step
Process Sub-Steps
Inputs
Wafer
Inspection
Detailed inspection of the wafer to determine if
there are any cracks or defects that might
otherwise make the wafer unsuitable.
Energy: 0.03 kWh/wafer
P contact
• Cleaning
• Silver (Ag) Deposition (PVD -
0.097µm)
• Ti Deposition (PVD : 0.103µm)
• W Deposition (PVD : 0.681µm)
• Measurement
•
Cleaning
Target Ag 0.44 mm3/wafer
Target Ti 0.47 mm3/wafer
Target W 3.09 mm3/wafer
UPW7 60.00 l/wafer
N2 0.70 m3/wafer
Energy: 1.19 kWh/wafer
N contact
Opening
• Litho 1 - Coatings
• Litho 1 - Baking
• Litho 1 - Stepper
• Litho 1 - Development
• Measurement
• Wet Etching Ti + W
• Wet Etching Ag
• Photoresist Removal
• Measurement
• Cleaning
• Litho 2 - Coating
• Litho 2 - Baking
• Litho 2 - Stepper
• Litho 2 - Development
• Measurement
• GaN Etching (1.5µm)
• Photoresist Removal
• Measurement
•
Cleaning
Acetone 0.20 l/wafer
Developer 50.00 ml/wafer
Etchant Ag 30.00 ml/wafer
Etchant Metal 60.00 ml/wafer
GaN Etchant 0.19 l/wafer
Photoresist 8.00 ml/wafer
UPW 60.00 l/wafer
N2 0.70 m3/wafer
Energy: 2.30 kWh/wafer
7 UPW is an abbreviation for Ultra Pure Water
Page 31
Processing
Step
Process Sub-Steps
Inputs
GaN Pattern
• Dielectric (CVD : 400nm)
• Measurement
• Cleaning
• Litho 3 - Coating
• Litho 3 - Baking
• Litho 3 - Stepper
• Litho 3 - Development
• Measurement
• Dielectric Etching
• Photoresist Removal
• Measurement
• Cleaning
Acetone 0.10 l/wafer
Developer 25.00 ml/wafer
Photoresist 4.00 ml/wafer
SF6 0.10 l/wafer
SiH4 0.18 g/wafer
UPW 60.00 l/wafer
N2 0.70 m3/wafer
O2 2.00 m3/wafer
Energy 2.71 kWh/wafer
N Contact
• Litho 4 - 2 Coating
• Litho 4 - Baking
• Litho 4 - Stepper
• Litho 4 - Development
• Measurement
• Cleaning
• Al Deposition (PVD : 0.284µm)
• Ni Deposition (PVD : 0.069µm)
• Gold-Tin (ECD : 3.256µm)
• N Contact- PR Removal
• Measurement
•
Cleaning
Acetone 0.10 l/wafer
AuSn 14.77 mm3/wafer
Developer 40.00 ml/wafer
Photoresist 7.00 ml/wafer
Target Al 1.27 mm3/wafer
Target Ni 0.42 mm3/wafer
UPW 60.00 l/wafer
N2 0.70 m3/wafer
Energy 1.13 kWh/wafer
Other
• Back Grinding Sapphire
• Fine grinding Sapphire - 75µm
• Scribe laser
•
Break substrate
Energy 2.47 kWh/wafer
Source: Yole Développement and System Plus Consulting.
The following table summarizes all the materials and energy consumed in this second stage of LED
manufacturing, the LED die fabrication stage. This table combines the material and energy consumption
of both the epitaxy and P-N junction deposition stage and post-epitaxy steps associated with contacts,
patterning, substrate removal and preparing finished LED die. The second and third columns of the table
specify the quantity of material used (presented with the units), and the right two columns provide the
unique ID and description of the Ecoinvent database record to which it is matched.
Page 32
Table 5-6. Energy and Material Consumption for LED Die Fabrication
Material
Quantity Consumed
Eco-ID Ecoinvent Description
Volume / Wafer
Mass / Wafer
Acetone
0.59 l/wafer
467 g/wafer
363
acetone, liquid, at plant
AuSn solder
14.8 mm3/wafer
0.29 g/wafer
10107
gold, from combined metal production,
at refinery
Developer
115 ml/wafer
115 g/wafer
264
chemicals inorganic, at plant
Etchant Ag
30 ml/wafer
30 g/wafer
283
hydrogen fluoride, at plant
Etchant Metal
60 ml/wafer
60 g/wafer
283
hydrogen fluoride, at plant
GaN Etchant
0.192 l/wafer
192 g/wafer
283
hydrogen fluoride, at plant
H2
1.62 m3/wafer
136 g/wafer
286
hydrogen, liquid, at plant
N2
4.42 m3/wafer
5527 g/wafer
300
nitrogen, liquid, at plant
NH3
0.447 kg/wafer
447 g/wafer
246
ammonia, liquid, at regional storehouse
O2
2 l/wafer
2.3 kg/wafer
301
oxygen, liquid, at plant
Photoresist
19 ml/wafer
19 g/wafer
382
chemicals organic, at plant
Energy
42.57 kWh/wafer
42.57 kWh/wafer
6694
electricity mix
SF6
0.1 l/wafer
13 g/wafer
348
sulfur hexafluoride, liquid, at plant
SiH4
0.242 g/wafer
0.242 g/wafer
321
silicon carbide, at plant
Slurry
2.3 l/wafer
2.3 kg/wafer
1997
zeolite, slurry, 50% in H2O, at plant
Target Ag
0.44 mm3/wafer
0.005 g/wafer
10122
silver, from combined gold-silver
production, at refinery
Target Al
1.27 mm3/wafer
0.003 g/wafer
1056
aluminum, production mix, at plant
Target Ni
0.417 mm3/wafer
0.004 g/wafer
1121
nickel, 99.5%, at plant
Target Ti
0.467 mm3/wafer
0.002 g/wafer
355
titanium dioxide, production mix, at
plant
Target W
3.089 mm3/wafer
0.06 g/wafer
8143
palladium, secondary, at precious metal
refinery
TMAl
0.003 g/wafer
0.003 g/wafer
1056
aluminum, production mix, at plant
TMGa
1.47 g/wafer
1.47 g/wafer
6908
gallium, semiconductor-grade, at plant
TMIn
0.01 g/wafer
0.01 g/wafer
7164
indium, at regional storage
UPW
240 l/wafer
240 kg/wafer
7237
water, ultrapure, at plant
Page 33
5.2.3 Packaged LED Assembly
This third phase of LED manufacturing is referred to as the “packaging” of the device. It involves taking
the LED die, mounting it in housing, making electrical connections, applying phosphor, encapsulant and
optics. It also involves testing and binning the LED into the correctly classified product.
Table 5-7. Steps Associated with LED Packaging and Assembly
Processing Step
Description
Inputs
Package Element
Building
The ceramic substrate (2-layers of alumina) are prepared for
mounting the LED chip.
0.01 kWh / LED
13.5 mm
2
Alumina / LED
Stud Bumping
Wire bonding process, where gold is bonded to the die pad.
0.001 kWh / LED
0.004 mm
3
gold / LED
Reflow
The LED is heated to a temperature above the melting point
of the solder, but below the temperature that may damage
other parts of the LED package.
0.003 kWh / LED
LED &
Protective die
attach
The LED is attached to the package element, incorporating
protection against electrostatic discharge (ESD).
0.003 kWh / LED
0.220 mm2 ESD diode
(silicon) / LED
Reflow
The LED is heated again to the melting point of solder.
0.003 kWh / LED
Under filling
Underfill (i.e., an organic polymer and inorganic filler) is
added to the package that provides support to the solder ball
interconnect.
0.003 kWh / LED
0.05 mm3 underfill / LED
Phosphor
Application of a Ce3+:YAG phosphor coating that will
convert a portion of the blue light emission from the LED
die to longer wavelengths which gives the packaged LED
emission the appearance of white light.
0.000 kWh / LED
0.192 mm3 phosphor / LED
Lens
An optical lens that gathers and directs the light in the
appropriate beam angle for the desired application.
0.003 kWh / LED
8.400 mm
3
silicon / LED
Annealing
The package is heated to anneal together the polymer,
phosphor and lens into one cohesive unit.
0.003 kWh / LED
Substrate Dicing
The substrate is cut into the individual packaged LEDs for
use.
0.001 kWh / LED
Source: Yole Développement and System Plus Consulting for quantities of process inputs.
Page 34
Figure 5-2. Example of the Finished Packaged LED, the Philips Luxeon Rebel
Taking into account all the inputs for LED packaging and assembly presented in Table 5-7, the following
table presents the aggregate consumption per LED produced. The middle columns of the table specifies
the quantity of material used (presented with the units), and the right two columns provide the unique ID
and description of the Ecoinvent database record to which it is matched.
Table 5-8. Energy and Material Consumption for LED Packaging Assembly
Stage Material Used
Amount
Eco-ID Ecoinvent Description
Volume per LED
Mass per LED
Material
Ceramic Substrate
(2-layer Alumina)
13.5 mm2/LED
0.0135 g/LED
244
aluminum oxide, at plant
Production
Energy (kWh)
0.03 kWh/LED
0.03 kWh/LED
6693
electricity mix for China
Material
ESD diode
(Silicon)
0.22 mm2/LED
0.055 g/LED
7111
diode, unspecified, at plant
Material
Gold
0.004 mm3/LED
0.00006 g/LED
10107
gold, from combined metal
production, at refinery
Material
Underfill
0.05 mm3 / LED
0.0196 g/LED
324
silicone product, at plant
Material
Silicone
8.4 mm3/LED
0.00006 g/LED
1802
epoxy resin, liquid, at plant
Page 35
5.3 LED Lamp Analysis
After preparing an Ecoinvent inventory of the materials and processes that
contribute to the production of a packaged LED, the next step in the
analysis is to consider installing several of these packaged LEDs into a
self-ballasted LED lamp that can be inserted into a mains voltage socket.
For the purposes of this study (and not as an endorsement of the product)
we selected the Philips EnduraLED lamp that was introduced in 2011 and
was commonly available in the U.S. market in 2012. There is a picture of
this lamp on the right.
The table below presents the materials used in manufacturing the LED
lamp and accounts for the energy involved in the assembly and
manufacturing steps. The finished LED lamp weighs 178 grams and the
card-stock packaging was measured at 37 grams, taken together the lamp
inside the box totals approximately 215 grams.
The table estimates the transport of the lamp from China to the U.S. by sea and then a further 1000
kilometers distribution within the U.S. The table presents the energy consumed by the lamp over its
lifetime – specifically, 12.5 watts times 25000 hours, or 312.5 kilowatt-hours. Finally, in the end of life
stage, the table presents some estimates of the rates of recycling, with the LED lamp being recycled 20%
of the time and the packaging 30% of the time. The middle column of the table specifies the quantity of
material used (presented with the units), and the right two columns provide the unique ID and description
of the Ecoinvent database record to which it is matched.
Table 5-9. LCA Inventory for the 12.5 Watt LED Lamp in 2012
Stage
Material Used
Amount
Eco-ID
Ecoinvent Description
Material
LEDs (blue light)
12 units
LED impacts taken from the above section
Material
Remote phosphor
1.0g
6954
rare earth concentrate, 70% rare earth oxide (REO),
from bastnasite, at beneficiation
Material
Plastic phosphor
host
11.1g
6954
rare earth concentrate, 70% REO, from bastnasite, at
beneficiation
Material
Aluminum heat
sink
68.2g
1057
aluminum, production mix, cast alloy, at plant
Material
Copper
5.0g
1084
copper, primary, at refinery
Material
Nickel
0.003g
1121
nickel, 99.5%, at plant
Material
Brass
1.65g
1066
brass, at plant
Material
Cast iron
4.0g
1069
cast iron, at plant
Material
Chromium
0.0002g
1072
chromium steel 18/8, at plant
Material
Inductor
5 pcs.
1074
copper, at regional storage
Material
IC chip
2.0g
7016
integrated circuit, IC, logic type, at plant
Material
Capacitor SMD
8 pcs.
7010
capacitor, SMD type, surface-mounting, at plant
Material
Electrolytic
Capacitor
6 pcs.
7011
capacitor, electrolyte type, < 2cm height, at plant
Page 36
Stage
Material Used
Amount
Eco-ID
Ecoinvent Description
Material
Diode
6 pcs.
7075
diode, glass-, SMD type, surface mounting, at plant
Material
Printed Wiring
Board
15.0g
10995
printed wiring board, surface mount, lead-free
surface, at plant
Material
Resistor SMD
35 pcs.
7068
resistor, SMD type, surface mounting, at plant
Material
Resistor
3 pcs.
7109
resistor, wirewound, through-hole mounting, at plant
Material
Transistor
6 pcs.
7113
transistor, wired, big size, through-hole mounting, at
plant
Material
Resin Glue
4.5g
1802
epoxy resin, liquid, at plant
Material
Solder paste
0.3g
10800
flux, wave soldering, at plant
Production
Power
5.0 MJ
6693
electricity mix for China
Production
Manufacturing
178g
10169
assembly, LCD screen
Material
Packaging
37g
1698
packaging, corrugated board, mixed fiber, single
wall, at plant
Transport
Sea - 215g
10000 km
1968
transport, transoceanic freight ship
Transport
Road - 215g
1000 km
1943
transport, truck >16t, fleet average
Use
Energy in use
312.5 kWh
6694
electricity mix for the U.S.
End of Life
Lamp, Recycling
20%
10977
disposal, treatment of CRT glass
End of Life
Lamp, Landfill
80%
2071
disposal, glass, 0% water, to inert material landfill
End of Life
Package, Recycling
30%
1693
corrugated board, recycling fiber, single wall, at plant
End of Life
Package, Landfill
70%
2077
disposal, packaging cardboard, 19.6% water, to inert
material landfill
Compared with the LED fabrication step of the manufacturing process, this stage (i.e., lamp assembly,
transport, use and disposal) of the LCA study had some very good matches between the material used in
the lamp and the options in the Ecoinvent database. It should be noted that there are two different
electricity values used in the analysis – a mix of electricity for China which is used at the manufacturing
stage and a mix of electricity for the U.S. which is used for the energy in use stage. It is important that the
energy in use stage reflect the mix where the lamp is being used because the magnitude of the impact
associated with the electricity consumed during the use phase is later found to be very important. The
recycling levels are meant to represent levels that would be commonly found in the U.S. for the different
materials – the lamp and its packaging.
As discussed earlier, in addition to considering the LCA impacts of the incandescent, CFL and LED
lamps in 2012, the authors also examined the impacts of the projected performance of LED lamps in
2017. This is of particular interest because LEDs are a rapidly evolving technology and expectations are
that it will continue to achieve substantial improvements in its performance in the coming years (DOE,
2012b). In order to determine the performance of a 2017 lamp, the 2012 LED lamp analysis was modified
as detailed in the list below:
Page 37
• Efficacy improvement from 65 lm/W (Philips EnduraLED lamp) to 134 lm/W system output –
this adjustment is based on the projected performance improvement of warm-white LEDs in
Figure 5.5 and Table 5.6 of the U.S. DOE 2012 Multiyear Program Plan (DOE, 2012b).
• Reduce wattage for the lamp in order to hold lumen output at approximately the equivalent of a
60 watt incandescent lamp. Wattage is reduced from 12.5W to 6.1W while lumen output is
adjusted from 812 to 824 lumens.
• Lamp lifetime will increase, benefitting from less heat generated in the lamp itself and
improvements in the LEDs and the drive electronics. The lifetime is adjusted from 25,000 to
40,000 hours.
• LED manufacturing improvements in the MOCVD reactors and migration to larger wafer sizes
will result in LED die yield improvements. Presently, the model is running on the assumption of a
69% yield on a 3-inch wafer, producing 2438 units. By 2017, the wafer sizes will have increased
and yield will have increased such that the expect yield relative to a 3-inch wafer would be
approximately 92% (3250 units). The model is therefore adjusted to reflect this yield rate, which
is equivalent to a 52% yield on a 4-inch wafer, a very conservative estimate.
• Fewer LEDs in the lamp – given expected improvements in efficacy and package power handling
capability, luminous flux output is projected to increase, and thus fewer LEDs will be needed in
the finished product to achieve the equivalent light output. For the 2017 lamp, it is assumed that
only 12 LEDs will be used (whereas the 2012 lamp uses 18).
• Smaller heat sink – given that the power consumption of the lamp will be decreasing (from
12.5 W to 6.1 W, the heat sink mass necessary to conduct and disperse the heat will be smaller. It
is assumed that the mass of the heat sink will be reduced proportionally with power reduction
(i.e., 6.1/12.5).
• Fewer input chemicals needed for epitaxy – it is assumed that manufacturing processes will
continue to advance, and chemicals required in the epitaxy and growth of LED die will decrease
by 20%. Thus the input chemicals necessary for the creating the LED die are reduced by 20%.
This adjustment does not, however, apply to the wafer preparation stage or the packaging of the
LED, these are both assumed to remain constant.
• Redesign of the LED driver – it is expected that the LED driver component count will decrease as
more sophisticated drivers are developed that reduce size and increase reliability of the driver.
For 2017, the model assumes that there will be a 50% increase in the Integrated Circuit (IC) chips
used in the LED driver and a 33% reduction in the number of individual components such as
resistor, capacitors and diodes.
• Improvement in waste management – the model also considers the end-of-life stage, and for
2017, it is assumed that there will be slightly higher proportions of lamp and packaging recycling.
Thus, the model assumes an improvement from 20% recycling of the LED lamp in 2012 to 30%
in 2017. The model also assumes the packaging recycling rate increases from 30% in 2012 to
50% in 2017.
To provide more detail on these changes to the underpinning LED technology and lamp design, the table
below provides an entry for each of the input variables that was changed from the 2012 to the 2017 lamp.
The Ecoinvent records to which each of the materials and processes were matched in 2012 remained the
same in 2017.
Page 38
Table 5-10. Changes to LCA Inputs for LED Lamp Manufacturing in 2017
Material for
Manufacturing
Quantity in
2012
Quantity in
2017
Units
Percentage
Reduction / Increase
Acetone
0.59
0.472
l/wafer
20%
AuSn solder
14.8
11.817
mm3/wafer
20%
Developer
115
92
ml/wafer
20%
Etchant Ag
30
24
ml/wafer
20%
Etchant Metal
60
48
ml/wafer
20%
GaN Etchant
0.192
0.154
l/wafer
20%
H2 gas
1.62
1.296
m3/wafer
20%
N2 gas
4.42
3.536
m3/wafer
20%
NH3 gas
0.447
0.358
kg/wafer
20%
O2 gas
2
1.6
l/wafer
20%
Photoresist
19
15.2
ml/wafer
20%
Power
42.57
34.06
kWh/wafer
20%
SF6
0.1
0.08
l/wafer
20%
SiH4
0.242
0.194
g/wafer
20%
Slurry
2.3
1.84
l/wafer
20%
Target Ag
0.44
0.352
mm3/wafer
20%
Target Al
1.27
1.016
mm3/wafer
20%
Target Ni
0.417
0.334
mm3/wafer
20%
Target Ti
0.467
0.374
mm3/wafer
20%
Target W
3.089
2.471
mm3/wafer
20%
TMAl
0.003
0.002
g/wafer
33%
TMGa
1.47
1.176
g/wafer
20%
TMIn
0.01
0.008
g/wafer
20%
UPW
240
192
l/wafer
20%
LEDs (blue light)
18
12
packaged LEDs
33%
Aluminum heat sink
0.0682
0.032736
kg
49%
IC chip
0.002
0.003
kg
-50% (increase)
Electrolytic Capacitor
6
4
pieces
33%
Diode
6
4
pieces
33%
Resistor SMD
35
23
pieces
34%
Resistor
3
2
pieces
33%
Transistor
6
4
pieces
33%
Lamp Weight
0.178
0.143
kg
20%
Total Lamp+Pack Weight
0.215
0.18
kg
16%
Manufacturing
0.178
0.143
kg
20%
Energy in Use
312
240
kWh
23%
End of Life - lamp
20%
30%
Recycling
-50% (increase)
End of Life - lamp
80%
70%
Landfill
13%
End of Life - packaging
30%
50%
Recycling
-67% (increase)
Page 39
Material for
Manufacturing
Quantity in
2012
Quantity in
2017
Units
Percentage
Reduction / Increase
End of Life - packaging
70%
50%
Landfill
29%
Comparing our findings to those presented in the Part 1 report, there is very good alignment for the
energy in use phase for the LED lamp where we estimate that this phase represents on average 81% of the
impacts associated with this lamp. In Part 1, it was reported that the primary energy in use 3,540 MJ per
20 megalumen-hours of lighting service. In Part 2, we calculate 3,527 MJ for the same lighting service
(converted using an average power plant heat rate of 10,633 BTU/kWh for 2011 (DOE, 2012c). This
shows that for the most important stage of the LCA, there is very good alignment between the two
studies.
5.4 Incandescent Lamp Analysis
In order to benchmark the environmental impact of the LED lamp against a familiar
light source, an inventory of materials and processes was developed for a 60 watt A-
19 general lighting service incandescent lamp. The table below presents the
materials used in manufacturing the lamp, and accounts for the energy involved in
the glasswork and other manufacturing steps. The lamp itself weighs 38.2 grams and
the card-stock packaging was measured at 40 grams, taken together the lamp inside
the box totals approximately 78.2 grams.
The table estimates the transport of the lamp from China to the U.S. by sea and then
a further 1000 kilometers distribution within the U.S. The table presents the energy
consumed by the lamp over its lifetime – specifically, 60 watts times 1500 hours, or
90 kilowatt-hours. Finally in the end of life stage, the table presents some estimates
of the rates of recycling, with the lamp being recycled 10% of the time and the packaging 30% of the
time. The middle column of the table specifies the quantity of material used (presented with the units),
and finally, the material or process in the Ecoinvent database to which it was matched is provided. The
table shows both the unique Ecoinvent ID for each matched material or process and the database
description.
Table 5-11. LCA Inventory for the 60 Watt Incandescent Lamp
Stage
Material Used
Amount
Eco-ID
Ecoinvent Description
Material
Argon gas
0.137g
252
argon, liquid, at plant
Material
Nitrogen gas
0.845g
300
nitrogen, liquid, at plant
Material
Oxygen gas
7.290g
301
oxygen, liquid, at plant
Material
Hydrogen gas
0.001g
286
hydrogen, liquid, at plant
Material
Ammonia
0.085g
246
ammonia, liquid, at regional storehouse
Material
Aluminum
1.150g
1056
aluminum, production mix, at plant
Material
Brass
0.050g
1066
brass, at plant
Material
Resin Glue
1.550g
1802
epoxy resin, liquid, at plant
Material
Solder paste
0.150g
10800
flux, wave soldering, at plant
Page 40
Stage
Material Used
Amount
Eco-ID
Ecoinvent Description
Material
Glass Bulb
22.54g
810
glass tube, borosilicate, at plant
Material
Getter
0.002g
311
phosphoric acid, industrial grade, 85% in H2O
Material
Glass Flare
2.097g
810
glass tube, borosilicate, at plant
Material
Exhaust Tube
2.165g
810
glass tube, borosilicate, at plant
Material
Lead wire
0.100g
1178
wire drawing, copper
Material
Molybdenum
support wire
0.013g
1116
molybdenum, at regional storage
Material
Filament - Tungsten
0.010g
1142
rhodium, at regional storage
Production
Power
0.372g
6693
electricity mix for China
Production
Manufacturing
38.2g
10169
assembly, LCD screen
Material
Packaging
40.0g
1698
packaging, corrugated board, mixed fiber, single
wall, at plant
Transport
Sea – 78.2g
10,000 km
1968
transport, transoceanic freight ship
Transport
Road – 78.2g
1000 km
1943
transport, truck >16t, fleet average
Use
Energy in use
90.0 kWh
6694
electricity mix for the U.S.
End of Life
Lamp, Recycling
10%
10977
disposal, treatment of CRT glass
End of Life
Lamp, Landfill
90%
2071
disposal, glass, 0% water, to inert material landfill
End of Life
Package, Recycling
30%
1693
corrugated board, recycling fiber, single wall, at plant
End of Life
Package, Landfill
70%
2077
disposal, packaging cardboard, 19.6% water, to inert
material landfill
Overall, there were very good matches between the material used in the incandescent lamp and the
options available in the Ecoinvent database. All of the gases used in the manufacturing and filling of the
lamp were available, the metals and the glass were prepared. It should be noted that there are two
different electricity values used in the analysis – there is a mix of electricity for China which is used at the
manufacturing stage and a mix of electricity for the U.S. which is used for the energy in use stage. It is
important that the energy in use stage reflect the mix where the lamp is being used because the magnitude
of the impact associated with the electricity consumed during the use phase is later found to be the
dominant factor in the environmental impact associated with this lamp. The recycling levels are meant to
represent levels that would be commonly found in the U.S. for the different materials – the lamp and its
packaging.
Comparing our findings to those presented in the Part 1 report, there is very good alignment for the
energy-in use phase of the incandescent lamp which represents on average 93% of the impacts associated
with this lamp. In Part 1, it was reported that the primary energy in use 15,100 MJ per 20 megalumen-
hours of lighting service. In Part 2, we calculate 14,960 MJ for the same lighting service (converted using
an average power plant heat rate of 10,633 BTU/kWh for 2011 (DOE, 2012c)). This shows that for the
most important stage of the LCA, there is very good alignment between the two studies.
Page 41
5.5 Compact Fluorescent Lamp Analysis
In addition to comparing the LED lamp against an incandescent lamp, it is also
important to compare the LED lamp with the most common energy-efficient light
source used in the U.S. today, a CFL. The CFL is a miniaturized version of the
large linear tube fluorescent systems commonly found in commercial office
buildings. The linear tube has been bent and twisted to conform to a smaller
form-factor and the electronic ballast is contained in the base of the lamp, rather
than being a separate component wired to sockets. The glass tube is permanently
attached to the lamp base / ballast, and the system is designed to operate for
approximately 8,000 hours, after which the entire lamp is either recycled or
disposed.
The inventory of materials and processes presented in the table below were developed for a 15 watt
integrally-ballasted CFL. The table below presents the materials used in manufacturing the lamp and
ballast. The lamp itself weighs 153 grams and the card-stock packaging was measured at 81 grams, taken
together the lamp inside the box totals approximately 234 grams.
The table estimates the transport of the lamp from China to the U.S. by sea and then a further 1000
kilometers distribution within the U.S. The table presents the energy consumed by the lamp over its
lifetime – specifically, 15 watts times 8000 hours, or 120 kilowatt-hours. Finally, in the end of life stage,
the table presents some estimates of the rates of recycling, with the CFL being recycled 20% of the time
and the packaging 30% of the time. The middle column of the table specifies the quantity of material used
(presented with the units), and finally, the material or process in the Ecoinvent database to which it was
matched is provided. The table shows both the unique Ecoinvent ID for each matched material or process
and the database description.
Table 5-12. LCA Inventory for the 15 Watt Integrally Ballasted Compact Fluorescent Lamp
Stage
Material Used
Amount
Eco-ID
Ecoinvent Description
Material
Argon gas
0.004g
252
argon, liquid, at plant
Material
Nitrogen gas
0.119g
300
nitrogen, liquid, at plant
Material
Oxygen gas
0.159g
301
oxygen, liquid, at plant
Material
Hydrogen gas
0.002g
286
hydrogen, liquid, at plant
Material
Neon gas
0.0004g
294
krypton, gaseous, at plant
Material
Noble Earths
0.001g
6954
rare earth concentrate, 70% REO, from bastnasite, at
beneficiation
Material
Yttrium Oxide
1.37g
6954
rare earth concentrate, 70% REO, from bastnasite, at
beneficiation
Material
Ammonia
0.13g
246
ammonia, liquid, at regional storehouse
Material
Nitric acid
7.9g
299
nitric acid, 50% in H2O, at plant
Material
Sulfuric acid
1.67g
350
sulfuric acid, liquid, at plant
Material
Aluminum Oxide
0.008g
244
aluminum oxide, at plant
Material
Lead
0.19g
1103
lead, at regional storage
Page 42
Stage
Material Used
Amount
Eco-ID
Ecoinvent Description
Material
Copper
0.402g
1084
copper, primary, at refinery
Material
Nickel
0.003g
1121
nickel, 99.5%, at plant
Material
Brass
1.65g
1066
brass, at plant
Material
Cast iron
0.029g
1069
cast iron, at plant
Material
Chromium
0.0002g
1072
chromium steel 18/8, at plant
Material
Mercury
0.004g
1111
mercury, liquid, at plant
Material
Capacitor
40 pcs.
7010
capacitor, SMD type, surface-mounting, at plant
Material
Coil miniature
3 pcs.
10155
inductor, miniature RF chip type, MRFI, at plant
Material
Diode SMD
40 pcs.
7075
diode, glass-, SMD type, surface mounting, at plant
Material
PWB
3.7g
10995
printed wiring board, surface mount, lead-free
surface, at plant
Material
Resistor SMD
40 pcs.
7068
resistor, SMD type, surface mounting, at plant
Material
Thermistor, NTC
0.19g
7068
resistor, SMD type, surface mounting, at plant
Material
Transistor power
large
3.70g
7113
transistor, wired, big size, through-hole mounting, at
plant
Material
Resin Glue
4.5g
1802
epoxy resin, liquid, at plant
Material
Solder paste
0.3g
10800
flux, wave soldering, at plant
Material
Glass Tube
1.20g
810
glass tube, borosilicate, at plant
Material
Housing top &
bottom (PBTP)
2.39g
1827
polyethylene terephthalate, granulate, amorphous, at
plant
Production
Natural Gas
10.7kg
8338
metal working factory operation, heat energy from
natural gas
Production
Power
3.13MJ
6693
electricity mix for China
Production
Manufacturing
153g
10169
assembly, LCD screen
Material
Packaging
81g
1698
packaging, corrugated board, mixed fiber, single
wall, at plant
Transport
Sea - 234g
10000km
1968
transport, transoceanic freight ship
Transport
Road - 234g
1000km
1943
transport, truck >16t, fleet average
Use
Energy in use
120 kWh
6694
electricity mix for the U.S.
End of Life
Lamp, Recycling
20%
10977
disposal, treatment of CRT glass
End of Life
Lamp, Landfill
80%
2071
disposal, glass, 0% water, to inert material landfill
End of Life
Package, Recycling
30%
1693
corrugated board, recycling fiber, single wall, at plant
End of Life
Package, Landfill
70%
2077
disposal, packaging cardboard, 19.6% water, to inert
material landfill
Overall, the CFL is a complex system which includes the lamp, cathodes, a ballast, housing and a socket.
Across the list of materials and processes identified in manufacturing a CFL, there were good matches in
Page 43
the Ecoinvent database. For example, the components in the ballast were able to be matched one-for-one
with exactly the same component selected from the Ecoinvent database. As with the previous lamps
discussed, this table shows two different electricity values used in the analysis – there is a mix of
electricity for China which is used at the manufacturing stage and a mix of electricity for the United
States which is used for the energy in use stage. This differentiation is important because the magnitude
of the impact associated with the electricity consumed during the use phase is later shown to be a
significant factor in the environmental impact associated with this lamp. Finally, the recycling levels are
meant to represent levels that would be commonly found in the U.S. Compared with incandescent, it was
assumed that there is a slightly higher recycling rate of the lamp (20%) because of the mercury in the
glass tube.
Comparing our findings for this lamp to those presented in the Part 1 report, there is very good alignment
for the energy-in use phase of the incandescent lamp which represents on average 78% of the impacts. In
Part 1, it was reported that the primary energy in use 3,780 MJ per 20 megalumen-hours of lighting
service. In Part 2, we calculate 4,079 MJ for the same lighting service (converted using an average power
plant heat rate of 10,633 BTU/kWh for 2011 (DOE, 2012c)). This shows that for the most important stage
of the LCA, we are estimating approximately 8% higher energy consumption for the energy in use stage
of the LCA.
Page 44
6 Life Cycle Impact Assessment Indicators
This section of the report discusses the indicators that were selected from the Ecoinvent database for this
study. The inventories presented in Chapter 5 are combined with impact data from the Ecoinvent database
to determine the levels of environmental impact. For this study, DOE wanted to make sure the assessment
quantified impacts associated with air/climate, water, soil and resources. There were fifteen indicators
chosen for this study, as shown in Table 6-1. After the table, a brief description of each of these indicators
is provided.
Table 6-1. LCA Environmental Indicators Selected for this Analysis
Abbr.
Name
Indicator
Ecoinvent Indicator
Units
Air / Climate
GWP
Global Warming
Potential
greenhouse gas
emissions
global warming potential
(GWP100a) [CML2001]
kg CO
2
-eq
AP
Acidification Potential
air pollution
acidification potential
[CML2001]
kg SO
2
-eq
POCP
Photochemical Ozone
Creation Potential
air pollution
photochemical oxidation
[CML2001]
kg O
3
formed
ODP
Ozone Depleting
Potential
air pollution
stratospheric ozone depletion
(ODP10a)
kg CFC11-eq
HTP
Human Toxicity
Potential
toxicity
human toxicity (HTP100a)
[CML2001]
kg 1,4-DCB-
eq
Water
FAETP
Freshwater Aquatic
Ecotoxicity Potential
water pollution
freshwater aquatic ecotoxicity
(FAETP100a)
kg 1,4-DCB-
eq
MAETP
Marine Aquatic
Ecotoxicity Potential
water pollution
marine aquatic ecotoxicity
(MAETP100a) [CML2001]
kg 1,4-DCB-
eq
EP
Eutrophication Potential
water pollution
eutrophication potential
[CML2001]
kg PO
4
-eq
Soil
LU
Land Use
land use
land use [CML2001]
m2a
EDP
Ecosystem Damage
Potential
biodiversity
impacts
ecosystem damage potential
[EDP]
points
TAETP
Terrestrial Ecotoxicity
Potential
soil degrad. &
contamination
terrestrial ecotoxicity
(TAETP100a) [CML2001]
kg 1,4-DCB-
eq
Resources
ARD
Abiotic Resource
Depletion
resource
depletion
depletion of abiotic resources
[CML2001]
kg Sb-eq
NHWL
Non-Hazardous Waste
Landfilled
non-hazardous
waste
landfilling of bulk waste
[EDIP2003]
kg waste
RWL
Radioactive Waste
Landfilled
hazardous waste
landfilling of hazardous waste
[EDIP2003]
kg waste
HWL
Hazardous Waste
Landfilled
hazardous waste
landfilling of radioactive
waste [EDIP2003]
kg waste
In the above table, the far-right column identifies the units in which each of these environmental
indicators are measured. The abbreviation “eq” stands for equivalents which will often be used when
more than one pollutant can cause a particular impact. For example, global warming is attributed to a
number of gases, including carbon dioxide (CO2) and methane (CH4); however emissions are reported for
this indicator simply in units of “kg of CO2 equivalents.” On that basis, CO2 is said to have a global
Page 45
warming potential (GWP) of one because one kg of CO2 has the warming potential of itself, but methane
has a GWP of 25 (one kg of CH4 has the warming potential of 25 kg of CO2). By using equivalent values,
it simplifies the outputs of the LCA and facilitates comparisons between studies. Several other criteria are
reported in a similar way, notably the toxicity criteria, which are assessed relative to the toxicity of 1,4-
DiChloroBenzene (1,4-DCB), a known carcinogenic substance.
The following material provides a brief overview of each of the 15 environmental criteria against which
the incandescent, CFL and LED lamps are assessed.
Indicator: Global Warming Potential (GWP)
Measurement Units: kilograms of carbon dioxide (CO2) equivalents
Description: This indicator is a measurement of activities associated with the life cycle of the
product that alter the chemical composition of the atmosphere through the build-up of greenhouse
gases, primarily carbon dioxide, methane, and nitrous oxide. As these and other heat-trapping
gases increase their concentration, the heat-trapping capability of the earth’s atmosphere will also
increase, triggering global climate change and associated environmental impacts.
Indicator: Acidification Potential (AP)
Measurement Units: kilograms of sulfur dioxide (SO2) equivalents
Description: This indicator is a measure of the air pollution (mainly ammonia, sulfur dioxide and
nitrogen oxides) caused by the product’s life cycle which contributes to the deposition of acidic
substances. The resultant ‘acid rain’ is best known for the damage it causes to forests and lakes.
However, less well known impacts are the ways acidification affects freshwater and coastal
ecosystems, soils and even ancient historical monuments. Acid deposition can also increase the
environmental mobility of metals, resulting in the pollution of water sources and increased uptake
of metals (e.g., mercury) by biota.
Indicator: Photochemical Ozone Creation Potential (POCP)
Measurement Units: kilograms of ozone (O3) formed
Description: This indicator is a measure of the photochemical smog generated during the
product’s life cycle. Common sources include automobile internal combustion engines, as well as
the increased use of fossil fuels for heating, industry, and transportation. These activities lead to
emissions of two major primary pollutants, volatile organic compounds (VOCs) and nitrogen
oxides. Interacting with sunlight, these primary pollutants convert into various hazardous
chemicals known as secondary pollutants – namely peroxyacetyl nitrates (PAN) and ground-level
(tropospheric) ozone. These secondary pollutants cause what is commonly referred to as “urban
smog.”
Indicator: Ozone Depleting Potential (ODP)
Measurement Units: kilograms of CFC-11 equivalents
Description: This metric quantifies the ozone depleting potential of the product during its life
cycle. Although ground-level ozone is a pollutant, stratospheric ozone is beneficial, protecting the
earth from excessive amounts of ultraviolet light. The stratospheric ozone layer is attacked by
free radical catalysts, some of which are produced by many man-made chemicals such as
chlorofluorocarbons (CFCs) which were used as a blowing agent in aerosols and insulation and as
a working fluid in refrigerator compressors. This indicator adjusts all ozone depleting chemicals
associated with the UEL to the equivalent level of emissions of these harmful chemicals.
Page 46
Indicator: Human Toxicity Potential (HTP)
Measurement Units: kilograms of 1,4-dichlorobenzene (DCB) equivalents
Description: This indicator attempts to quantify the air, water and soil emissions associated with
the product’s life cycle that may be detrimental to human health. The toxicological factors are
calculated using scientific estimates for the acceptable daily intake or tolerable daily intake of the
toxic substances, but are still at an early stage of development, so can only be taken as an
indication and not as an absolute measure of the toxicity potential. The measurement units are in
equivalents of 1,4-dichlorobenzene, a known carcinogen.
Indicator: Freshwater Aquatic Ecotoxicity Potential (FAETP)
Measurement Units: kilograms of 1,4-dichlorobenzene (DCB) equivalents
Description: This indicator is very similar to human toxicity potential, but combines factors
associated with the maximum tolerable concentrations of different toxic substances in water by
freshwater aquatic organisms.
Indicator: Marine Aquatic Ecotoxicity Potential (MAETP)
Measurement Units: kilograms of 1,4-dichlorobenzene (DCB) equivalents
Description: This indicator is analogous to FAETP, combining factors associated with the
maximum tolerable concentrations of different toxic substances in water, but refers to marine
aquatic organisms.
Indicator: Eutrophication Potential (EP)
Measurement Units: kilograms of phosphate (PO4) equivalents
Description: Nitrates and phosphates are essential for life, but increased concentrations in water
can encourage excessive growth of algae, reducing the oxygen within the water and damaging
ecosystems – a phenomenon known as eutrophication.
Indicator: Land Use (LU)
Measurement Units: square meters per year (m2a), the product of m2 area and years
Description: Land use is an economic activity that generates large benefits for human society, but
it also has negative impacts on the environment. The occupation of a location by an industrial
facility precludes the return of that site to a more natural environment, including availability for
wildlife. The indicator captures the impact on both the area involved and the number of years
over which that occurs.
Indicator: Ecosystem Damage Potential (EDP)
Measurement Units: points
Description: Biodiversity has been negatively influenced by intensive agriculture, forestry and the
increase in urban areas and infrastructure. This indicator attempts to provide some measure of
that impact. It combines land-use and land transformation (both to and from industrial uses), and
assigns characterization factors to account for the relative impact of the land usage.
Indicator: Terrestrial Ecotoxicity Potential (TAETP)
Measurement Units: kilograms of 1,4-dichlorobenzene (DCB) equivalents
Description: This indicator is very similar to the previous toxicity potentials, but refers to the
maximum tolerable concentrations of different toxic substances by terrestrial organisms.
Page 47
Indicator: Abiotic Resource Depletion (ARD)
Measurement Units: Equivalent kilograms of the scarce element, antimony (Sb)
Description: The current levels of global resource consumption are widely acknowledged to be
unsustainable. Abiotic resources are natural, and essentially limited, resources, such as iron ore,
crude oil and natural gas, as opposed to renewable, biotic sources such as biomass. ARD impacts
are reported against the remaining global inventory of antimony (Sb), a relatively scarce element.
Indicators: Non-Hazardous Waste Landfilled (NHWL), Radioactive Waste Landfilled
(RWL), and Hazardous Waste Landfilled (HWL)
Measurement Units: Kilograms of each of these three land-fill processes
Description: For the products being considered in this LCA, these indicators all seek to quantify
the amount of materials sent to landfill, split between three categories – non-hazardous waste,
radioactive waste and hazardous waste.
Page 48
7 Life Cycle Assessment Results
Having identified the materials and processes being consumed for each of the lamp types in Chapter 5 and
selecting the fifteen environmental indicators in Chapter 6, this chapter presents the results of the
analysis. The first review is to determine which stages of the life-cycle assessment are significant and
which ones are negligible from an environmental impacts point of view. This analysis is important to
inform the sensitivity analysis, which will investigate significant assumptions and test whether
conclusions drawn are robust to plausible variations in the underlying data.
For each lamp type, the LCA impacts are calculated separately for the raw materials, the manufacturing,
the transport (by sea and by road), the power consumed during the lamp’s operating life and finally the
end of life. The following series of tables and bar charts present the LCA results for each lamp type,
broken down by these LCA stages. The values shown are in the units presented in Chapter 6 (and
repeated below), but normalized to represent the impact associated with 20 megalumen-hours of light.
This quantity of lighting service was used in DOE’s Part 1 study and is equal to the light output of the
12.5 Watt LED lamp (2012) over its rated lifetime.
GWP
Global Warming Potential
kg CO2-eq
AP
Acidification Potential
kg SO2-eq
POCP
Photochemical Ozone Creation Potential
kg O3 formed
ODP
Ozone Depleting Potential
kg CFC11-eq
HTP
Human Toxicity Potential
kg 1,4-DCB-eq
FAETP
Freshwater Aquatic Ecotoxicity Potential
kg 1,4-DCB-eq
MAETP
Marine Aquatic Ecotoxicity Potential
kg 1,4-DCB-eq
EP
Eutrophication Potential
kg PO4-eq
LU
Land Use
m2a
EDP
Ecosystem Damage Potential
points
TAETP
Terrestrial Ecotoxicity Potential
kg 1,4-DCB-eq
ARD
Abiotic Resource Depletion
kg Sb-eq
NHWL
Non-Hazardous Waste Landfilled
kg waste
RWL
Radioactive Waste Landfilled
kg waste
HWL
Hazardous Waste Landfilled
kg waste
Page 49
Table 7-1. Life Cycle Impacts of the 60W Incandescent Lamp
Figure 7-1. Proportions of the Life Cycle Impacts for the 60W Incandescent Lamp
Incandescent
LCA Stage GWP AP POCP ODP HTP FAETP MAETP EP
Raw Materials
6.28 0.90049 0.000604 0.00000069 3.224 2.9873 11.026 0.05847
Manufacturing
7.77 0.06905 0.000796 0.00000030 4.373 0.0405 0.901 0.02756
Transport
0.28 0.00387 0.000043 0.00000004 0.098 0.0017 0.107 0.00053
Energy in Use
1017.12 6.93390 0.044379 0.00001008 197.746 18.5601 99.647 1.85966
Disposal
0.19 0.00059 0.000035 0.00000003 0.045 0.0011 0.017 0.00031
TOTAL
1031.64 7.90790 0.045857 0.00001114 205.486 21.5907 111.698 1.94653
Incandescent
LCA Stage LU EDP TAETP ARD NHWL RWL HWL
Raw Materials
1.7476 1.1385 0.002262 0.0499 2.060 0.0003923 0.0007504
Manufacturing
0.7402 0.5534 0.001446 0.0447 2.321 0.0000822 0.0002103
Transport
0.0033 0.0026 0.000051 0.0020 0.019 0.0000044 0.0000038
Energy in Use
20.2769 15.2903 0.120488 7.5409 30.601 0.0421082 0.0224757
Disposal
0.0198 0.0122 0.000134 0.0014 0.949 0.0000024 0.0000032
TOTAL
22.7878 16.9970 0.124381 7.6389 35.950 0.0425895 0.0234434
Air
Water
Soil
Resources
Page 50
Table 7-2. Life Cycle Impacts of the Compact Fluorescent Lamp
Figure 7-2. Proportions of the Life Cycle Impacts for the Compact Fluorescent Lamp
CFL
LCA Stage GWP AP POCP ODP HTP FAETP MAETP EP
Raw Materials 10.680 0.29225 0.002879 0.00000117 9.007 0.5182 6.9088 0.10631
Manufacturing 16.560 0.08449 0.001215 0.00000120 4.677 0.3486 2.2256 0.03657
Transport 0.173 0.00237 0.000026 0.00000002 0.060 0.0010 0.0654 0.00032
Energy in Use 277.380 1.89095 0.012103 0.00000275 53.928 5.0615 27.1750 0.50715
Disposal 0.086 0.00029 0.000016 0.00000001 0.020 0.0005 0.0077 0.00014
TOTAL 304.879 2.27035 0.016239 0.00000515 67.692 5.9298 36.3825 0.65049
CFL
LCA Stage LU EDP TAETP ARD NHWL RWL HWL
Raw Materials 1.0292 0.7001 0.013140 0.08395 1.382 0.000801 0.001169
Manufacturing 0.7215 0.5433 0.002536 0.08566 2.995 0.000239 0.000350
Transport 0.0020 0.0016 0.000031 0.00121 0.012 0.000003 0.000002
Energy in Use 5.5297 4.1698 0.032858 2.05648 8.345 0.011483 0.006129
Disposal 0.0085 0.0052 0.000057 0.00063 0.555 0.000001 0.000001
TOTAL 7.2909 5.4200 0.048622 2.22793 13.289 0.012527 0.007651
Resources
Air
Water
Soil
Page 51
Table 7-3. Life Cycle Impacts of the 2012 LED Lamp
Figure 7-3. Proportions of the Life Cycle Impacts for the 2012 LED Lamp
LED-2012
LCA Stage GWP AP POCP ODP HTP FAETP MAETP EP
Raw Materials 12.752 0.118812 0.0020015 0.0000013575 13.2821 0.376537 6.4255 0.09046
Manufacturing 3.450 0.031194 0.0003134 0.0000000989 1.4660 0.015090 0.3198 0.00939
Transport 0.052 0.000708 0.0000078 0.0000000064 0.0180 0.000310 0.0196 0.00010
Energy in Use 234.756 1.600375 0.0102428 0.0000023255 45.6406 4.283750 22.9991 0.42922
Disposal 0.015 0.000059 0.0000027 0.0000000025 0.0035 0.000091 0.0014 0.00002
TOTAL 251.025 1.751148 0.0125682 0.0000037908 60.4102 4.675778 29.7654 0.52919
LED-2012
LCA Stage LU EDP TAETP ARD NHWL RWL HWL
Raw Materials 0.45011 0.33650 0.0069973 0.08918 4.3440 0.0008670 0.0028337
Manufacturing 0.26894 0.20316 0.0005715 0.02003 0.7873 0.0000281 0.0000658
Transport 0.00060 0.00048 0.0000093 0.00036 0.0035 0.0000008 0.0000007
Energy in Use 4.68000 3.52906 0.0278091 1.74047 7.0628 0.0097188 0.0051875
Disposal 0.00140 0.00085 0.0000089 0.00011 0.1692 0.0000002 0.0000003
TOTAL 5.40105 4.07005 0.0353961 1.85015 12.3668 0.0106149 0.0080880
Air
Water
Soil
Resources
Page 52
Table 7-4. Life Cycle Impacts of the 2017 LED Lamp
Figure 7-4. Proportions of the Life Cycle Impacts for the 2017 LED Lamp
LED-2017
LCA Stage GWP AP POCP ODP HTP FAETP MAETP EP
Raw Materials 6.995 0.059638 0.000980 0.000000856 7.5722 0.24578 4.0410 0.056569
Manufacturing 1.900 0.017255 0.000167 0.000000050 0.7461 0.00794 0.1658 0.004804
Transport 0.027 0.000365 0.000004 0.000000003 0.0093 0.00016 0.0101 0.000050
Energy in Use 113.837 0.776046 0.004967 0.000001128 22.1318 2.07726 11.1526 0.208135
Disposal 0.013 0.000046 0.000002 0.000000002 0.0031 0.00008 0.0012 0.000022
TOTAL 122.772 0.853350 0.006120 0.000002039 30.4625 2.33122 15.3707 0.269580
LED-2017
LCA Stage LU EDP TAETP ARD NHWL RWL HWL
Raw Materials 0.2547 0.18857 0.004386 0.04949 3.5353 0.0004879 0.0011664
Manufacturing 0.1404 0.10642 0.000306 0.01106 0.4023 0.0000144 0.0000327
Transport 0.0003 0.00025 0.000005 0.00019 0.0018 0.0000004 0.0000004
Energy in Use 2.2694 1.71130 0.013485 0.84398 3.4249 0.0047128 0.0025155
Disposal 0.0013 0.00080 0.000009 0.00010 0.0826 0.0000002 0.0000002
TOTAL 2.6661 2.00734 0.018191 0.90482 7.4469 0.0052157 0.0037152
Soil
Resources
Air
Water
Page 53
7.1 Discussion of Life Cycle Assessment Results
The four sets of results clearly show that the factor that dominates the majority of the environmental
indicators considered is ‘energy in use’ which is depicted in each figure with yellow shading. The
proportion of impact attributable to energy in use is particularly high for the 60 watt incandescent lamp,
where energy in use constitutes an average 93% of the fifteen impacts over the lifetime of the lamp. The
next most significant stage of the assessment is the raw materials which constitute on average about 5%
of the total impact, ranging from 13.8% for freshwater aquatic ecotoxicity potential to 0.6% for abiotic
resource depletion. Manufacturing is the third most significant step in the LCA, with an average impact
over the fifteen indicators of approximately 1.8%. The remaining two LCA steps – disposal and transport
– constitute 0.2% and 0.1% respectively, although the majority of the disposal impact is in non-hazardous
waste landfilled, where it represents 2.6% of that impact. Transportation was found to be virtually
negligible, even though the lamps in their packaging have traveled over 11,000 kilometers from factory to
home.
FAETP
For the CFL, the largest contributor to environmental impacts is energy, which represents at most 92.3%
of the impact (for abiotic resource depletion) and at least 53.4% (for ozone depleting potential). On
average, energy in use represents about 78% of the impact of a CFL. The next most significant stage of
the LCA is the raw materials, representing on average 13.6% of the impacts, with terrestrial ecotoxicity
potential being the most impacted with 23.3% overall. Manufacturing is the third most impactful step in
the LCA, with an average impact of approximately 8.2% overall. The remaining two LCA steps –
disposal and transport – constitute 0.3% and 0.1% respectively, although the majority of the disposal
impact is in non-hazardous waste landfilled, where it represents 4.2% of that impact. As with the
incandescent lamp, the impact associated with transport was found to be virtually negligible, even though
the packaged CFLs travel over 11,000 kilometers from factory to home.
For the LED lamp in 2012, the largest contributor to environmental impact is energy in use, which
represents an average of 81% across the fifteen indicators. The proportion of impact varies from a high of
94.1% for abiotic resource depletion to a low of 57.1% for non-hazardous waste landfill. The second most
significant impact is the raw materials used in manufacturing the LED lamp. These include a range of
components, the LEDs and the large heat sink. On average the impact from the raw materials is 16.8%,
with a high of 35.8% (for ozone depleting potential) and a low of 4.8% (for abiotic resource depletion).
Manufacturing is the third most impactful step in the LCA, with just 2.3% and the disposal and transport
impacts are extremely low, both less than 0.1%. As with the incandescent lamp and CFL, the packaged
LED Lamp is assumed to be transported over 11,000 kilometers by sea and road, but the impacts are
virtually negligible.
For the LED lamp in 2017, the profile is similar to that of the 2012 lamp, however the significance of
energy is diminished due to the fact that this lamp is considerably more efficacious. For this reason, the
other impacts are able to gain a slightly higher proportion of the relative impact for each of the fifteen
categories considered. In this analysis, energy in use represents an average of 78.2% of the impact,
followed by raw materials at 19.3% and manufacturing at 2.3%. The transportation and disposal of the
lamp are negligible, at less than 0.2% each.
Page 54
7.2 Comparative Results Between the Lamps
As well as understanding which parts of the life cycle are the main contributors to the overall
environmental impacts of each lamp analyzed, it is also important to compare the lamps themselves to
determine which have the smallest overall impact. The results of that analysis are presented in this
subsection of the report.
The table below presents the environmental impacts associated with air and climate for each of the lamp
types. Within each of the impact indicators, the values presented are comparable between the different
lamp types because the lighting service has been normalized to represent 20 Mlm-hr of light output.
Table 7-5. Air-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service
Lamp Type
Global
Warming
Potential
(GWP)
Acidification
Potential (AP)
Photochemical
Oxidation
(POCP)
Stratospheric
O3 depletion
(ODP)
Human
Toxicity
Potential
(HTP)
kg CO2-Eq
kg SO2-Eq
kg formed O
3
kg CFC-11-Eq
kg 1,4-DCB-Eq
Incandescent
1031.640
7.90790
0.0458570
0.0000111
205.4860
CFL
304.879
2.27035
0.0162390
0.0000052
67.6920
LED-2012
251.025
1.75115
0.0125682
0.0000038
60.4102
LED-2017
122.772
0.85335
0.0061200
0.0000020
30.4625
For global warming potential, the incandescent lamp has the largest CO2-equivalent emissions, with over
one tonne of emissions associated with the functional unit of 20 million lumen-hours of light. The CFL
lamp represents a 70% reduction over the incandescent lamp for equivalent lighting service. The LED
lamps are even better, offering a 76% reduction with the 2012 lamp and an 88% savings with the 2017
lamp.
For acidification potential, the trend is similar. The incandescent lamp causes the greatest impact, with 7.9
kilograms of sulfur dioxide equivalent emissions for 20 megalumen-hours of light. The CFL offers a
reduction of 71% over the incandescent and the two LED lamps offer a 78% and 89% reduction
respectively, greatly reducing the acidification potential.
Photochemical oxidation leads to urban smog, and the emissions of this air pollutant are the most severe
with the incandescent lamp. That lamp will emit approximately 46 grams of ozone for the functional unit
of light output. The CFL and both LED lamps offer savings over that baseline of 65%, 73% and 87%
respectively.
Stratospheric ozone depletion potential is highest with the incandescent baseline lamp. The other, more
efficacious lamps, offer savings potentials of between 53% and 82% when compared with the
incandescent baseline.
For human toxicity potential, the lamp with the highest impact for the functional unit of light output is the
incandescent lamp. The CFL offers a 67% reduction over incandescent and the two LED lamps offer a
71% and 85% savings potential in 2012 and 2017 respectively.
Page 55
The following table presents the environmental impacts associated with water-related indicators for each
of the lamp types, normalized for 20 Mlm-hr of light output.
Table 7-6. Water-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service
Lamp Type
Freshwater Aquatic
Ecotoxicity Potential
(FAETP)
Marine Aquatic
Ecotoxicity Potential
(MAETP)
Eutrophication
Potential (EP)
kg 1,4-DCB-Eq
kg 1,4-DCB-Eq
kg PO4-Eq
Incandescent
21.5907
111.6980
1.9465
CFL
5.9298
36.3825
0.6505
LED-2012
4.6758
29.7654
0.5292
LED-2017
2.3312
15.3707
0.2696
For freshwater aquatic ecotoxicity potential, the incandescent lamp has the largest impact, with over three
times the impact of the CFL and ten times the impact of the LED in 2017. The units for this
environmental indicator are reported in equivalent kilograms of “1,4-DCB” which is 1,4-
DiChloroBenzene, a known carcinogen. The LED lamp in 2012 offers a 78% reduction in this impact
compared to the incandescent lamp.
For marine aquatic ecotoxicity potential, the trend is similar. The incandescent lamp causes the greatest
impact, with 112 kilograms of 1,4-DiChloroBenzene equivalent emissions for 20 megalumen-hours of
light. The CFL offers a reduction of 67% over the incandescent and the two LED lamps offer a 73% and
86% reduction respectively, greatly reducing this environmental damage potential.
Eutrophication potential is the last indicator of water-related impacts, measuring the impact in terms of
kilograms of phosphate equivalents that could cause excessive algal growth in waterways reducing
oxygen in the water and damaging the ecosystem. The incandescent lamp will emit approximately 2
kilograms of phosphate equivalents over the 20 megalumen-hour lighting service functional unit. The
CFL is approximately 67% less than that with 0.65 kg, and the two LED lamps are even lower at 0.53 kg
and 0.27 kg in 2012 and 2017 respectively. The 2017 LED lamp represents an 8-fold reduction in the
damages measured by this environmental indicator.
The following table presents the environmental impacts associated with soil-related indicators for each of
the three lamp types, normalized for 20 Mlm-hr of light output.
Page 56
Table 7-7. Soil-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting Service
Lamp Type
Land Use (LU)
Ecosystem Damage
Potential (EDP)
Terrestrial Ecotoxicity
(TAETP)
m2a
points
kg 1,4-DCB-Eq
Incandescent
22.7878
16.9970
0.1244
CFL
7.2909
5.4200
0.0486
LED-2012
5.4011
4.0701
0.0354
LED-2017
2.6661
2.0073
0.0182
Land use is a measure of impact on both the area involved and the number of years over which that
impact occurs. Of the lamps considered, the incandescent lamp has the largest impact, with a value three
times higher than the CFL and four times higher than the LED in 2012. The land use equivalent for an
incandescent lamp providing 20 megalumen-hours of lighting service is 22.8 square meters per year. For
the same lighting service, a CFL reduces that impact by 68%. The LED lamps reduce it further still, to
only 5.4 square meters with the 2012 lamp and 2.5 square meters in 2017. These levels represent a 76%
and 88% reduction respectively when compared to the incandescent lamp.
For ecosystem damage potential, the trend is similar. The incandescent lamp causes the greatest impact,
with 17 points of ecosystem damage potential over the functional unit. The CFL offers a 68% reduction
over the incandescent and the two LED lamps offer a 76% and 88% reduction respectively, greatly
reducing the ecosystem damage potential.
Terrestrial ecotoxicity is measured in the 1,4-dichlorobenzene equivalents. The incandescent lamp was
found to cause the release of 0.12 kilogram equivalents of this carcinogen. Compared to that impact, the
CFL offers a reduction of 61%, lessening the impact to only 0.05 kilogram equivalents. The two LED
lamps are even lower at 0.035 kg and 0.018 kg in 2012 and 2017 respectively. The 2017 LED lamp
represents an 85% reduction over the incandescent lamp benchmark for the damages measured by this
environmental indicator.
The following table presents the four resource-related environmental indicators that were assessed for
each of the three lamp types, normalized for 20 Mlm-hr of light output.
Table 7-8. Resource-Related Environmental Impacts of the Lamps for 20 Mlm-hr of Lighting
Service
Lamp Type
Abiotic Resource
Depletion (ARD)
Non-Hazardous Waste
Landfill (NHWL)
Radioactive Waste
Landfill (RWL)
Hazardous
Waste Landfill
(HWL)
kg antimony-Eq
kg waste
kg waste
kg waste
Incandescent
7.6389
35.9500
0.0426
0.0234
CFL
2.2279
13.2890
0.0125
0.0077
LED-2012
1.8502
12.3668
0.0106
0.0081
LED-2017
0.9048
7.4469
0.0052
0.0037
Page 57
For the first of the resource-related environmental impacts, abiotic resource depletion potential has the
largest depletion of the metric used for this environmental indicator, kilograms of antimony equivalents
depleted. The incandescent lamp’s impact is approximately 7.6 kilograms, while the more efficient lamp
types offer a 71% (CFL) to 88% (LED in 2017) reduction over that baseline.
For non-hazardous waste landfill, the trend is similar. The incandescent lamp causes the greatest impact,
with 36 kilograms of non-hazardous waste equivalents for the functional unit of 20 megalumen-hours of
light. The CFL offers a reduction of 63% over the incandescent and the two LED lamps offer a 66% and
79% reduction respectively, greatly reducing the impact for this metric.
For radioactive waste landfill, the proportions of the reduction are nearly identical to that of the abiotic
resource depletion potential. The incandescent lamp generates 43 grams of radioactive waste landfill
equivalents, where the CFL and both LED lamps case the generation of substantially less waste. The CFL
offers a reduction of 71%, to just 12 grams per 20 megalumen-hours of lighting service. The LED lamp in
2012 offers a 75% savings at 11 grams and the 2017 lamp offers a substantial savings of 88% savings at
just 5 grams of radioactive waste landfill generated for the same light output.
For hazardous waste landfill, the trend is similar but not exactly the same. The incandescent lamp still has
the largest impact, with 23 grams of hazardous waste landfill generated. The LED in 2012 has the next
lower impact, with 8.1 grams, a 65% reduction. The CFL lamp is slightly lower than the LED with 7.7
grams, which represents a reduction of 67% over the baseline. And finally, the LED in 2017 has the
lowest impact overall, with only 3.7 grams of hazardous waste landfill, a reduction of 84%. The reason
that the LED lamp in 2012 has a slightly higher impact than the CFL is due to the manufacturing of the
large aluminum heat sink used in the LED lamp, which represents 20% of the total impact measured for
this metric. While these are the mean values reported, the difference between the two is within the error
margin for this study. Please see Annex A for a sensitivity analysis on this particular environmental
indicator (i.e., Hazardous Waste Landfill).
Setting the other stages of an LCA to one side, if a comparison is performed simply between the raw
material inputs of the lamp types studied in this analysis, the distribution of environmental impacts tends
to be greater for the more efficient lamps because they are more complex systems. The CFL and LED
lamps both make use of technology in order to reduce the watts of power consumed when producing light.
Since the energy-in-use is the dominant LCA stage in terms of impacts (see Figures 7-1 through 7-4), the
greater raw material impacts are justified on a life-cycle basis because these lamps reduce the overall
environmental impacts associated with the same lighting service. In the future, improvements in LED
manufacturing technology will improve efficacy and reduce costs facilitating the added benefit of lower
impacts in almost all respects than any of the competing products on a life-cycle basis, even before
accounting for the energy consumed in use.
7.3 Summary of the Environmental Impacts
To facilitate simpler interpretation of the results across the four lamps and the fifteen environmental
indicators, the results are also presented in two ‘spider graphs’ shown in Figure 7-5 and Figure 7-6. Each
radial line on the chart represents a different environmental impact, and the impacts are grouped into four
categories – air (orange), water (blue), soil (green) and resources (yellow). For each impact, whichever
lamp has the largest impact is plotted at the outer circumference, and the other products are then
normalized to that impact. Therefore, the distance from the center of the spider graph represents the
severity of the impact relative to that worst performer. The relative position of the points for the other
lamps demonstrates their relative environmental impact to that maximum. Therefore, the closer each point
Page 58
is to the center of the graph, the smaller that particular impact. Those lamps with most of their plotted
impacts close to the center of the web are generally the best performers from an environmental
perspective.
It is clear from Figure 7-5 that the incandescent lamp has the highest impact per unit lighting service of all
the sources considered (it occupies all of the outermost points on the chart). This result is intuitive
because this lamp has the lowest efficacy of all the lamps considered and energy in use was already
identified as the most significant indicator of environmental impact.
In all but one environmental indicator category (i.e., hazardous waste landfill), the next worst performer is
the CFL, followed by the LED lamp in 2012 and then the LED lamp in 2017. The actual difference
between the CFL and the LED for the hazardous waste to landfill category is 0.4 grams. The reason that
the LED lamp in 2012 has a slightly higher impact than the CFL is due to the manufacturing of the large
aluminum heat sink used in the LED lamp, which represents 20% of the total impact measured for this
metric.
Figure 7-5. Life-Cycle Assessment Impacts of the Lamps Analyzed Relative to Incandescent
The incandescent lamp has the highest impact per unit lighting service of all the lamps considered. This
finding is not a function of the material content, as the incandescent lamp has the lowest mass and is least
complex lighting system. Rather, it represents the very low efficacy of this light source, where large
Page: 59
quantities of energy are required to produce light. The high energy consumption per unit light output
causes substantial environmental impact and results in the incandescent lamp being the most
environmentally harmful across all fifteen impact measures.
The next worst performer is the compact fluorescent lamp, which has substantially lower impacts than
incandescent, but is slightly more harmful than the 2012 integrally ballasted LED lamp. This is true in all
but one category – hazardous waste landfill – where the manufacturing of the large aluminum heat sink
used in the LED lamp causes the impacts to be slightly greater than for the CFL. The best performing
light source is the projected LED lamp in 2017, which takes into account several projected improvements
in LED manufacturing, LED performance and driver electronics.
Figure 7-6 presents the same findings shown in Figure 1-1, but the graph has been adjusted to remove the
incandescent lamp and provide the impacts relative (primarily) to the CFL.
Figure 7-6. Life-Cycle Assessment Impacts of the CFL and LED Lamps Analyzed (Detail)
Overall, the impacts of the LED lamp in 2017 are significantly less than the incandescent, and about 70%
lower than the CFL and approximately 50% lower than the LED lamp in 2012, which itself is the best
available technology in 2012. The important finding from these graphs is not necessarily the minor
relative differences between the CFL and LED lamps, but instead the very significant reduction in
environmental impacts that will result from replacing an incandescent lamp. Environmental impact
reductions on the order of 3 to 10 times are possible across the indicators through transitioning the market
to these more efficacious light sources. These reductions are largely due to the reduction in energy
Page 60
consumption per unit light delivered in 2017. Thus, due to the dominant role of energy consumption in
driving the impacts, continued focus on efficacy targets and incentives is appropriate. Furthermore, the
greatest environmental impact after energy in-use for the LED sources is the manufacturing of the
aluminum heat sink, which can be reduced in size as the efficacy increases, and more of the input wattage
is converted to useful lumens of light (instead of waste heat).
7.3.1 Comparison with DOE Part 1 Study Findings
As discussed in Chapter 2 of this report, DOE published Part 1 of this LCA study earlier in 2012 (DOE,
2012a). The Part 1 study reviewed existing LCA literature, focusing on the energy consumed in
manufacturing and use of the lamps studied. The report compared existing life-cycle energy consumption
of an LED lamp to that of an incandescent lamp and a CFL based on ten key published studies.
As shown in Figure 2-1 of this report, the Part 1 report found that the life cycle energy consumption of
LED lamps and CFLs to be similar at approximately 3,900 MJ per 20 million lumen-hours of lighting
service. Incandescent lamps were found to consume approximately four times more energy
(approximately 15,100 MJ per 20 million lumen-hours).
In Figure 7-7, the equivalent findings of the Part 2 study are presented. In general, these findings largely
corroborated the Part 1 study results with only very slight differences. For incandescent lamps, the power
consumption in Part 2 was less than 1% lower than the Part 1 result. For CFLs, the Part 1 finding was
4.3% lower than the Part 2. For LED lamps, the Part 2 study was found to be lower than Part 1, however
this is to be expected as the Part 2 study is the first of its kind considering this relatively new lamp and the
Part 1 study is considering lamps that were analyzed in LCA studies already published.
Figure 7-7. Life Cycle Assessment Primary Energy for Lamps in Part 2 Study
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7.4 Data Quality Assessment
This section of the report considers the quality of the data underpinning the analysis. To document the
quality of the data collected in this life cycle inventory, the table below was prepared to rate each data
source based on key data quality criteria.
Table 7-9. Data Quality Ranking Based on Highest Value for this Goal and Scope (5 high, 1 low)
Reference
Time Related
Coverage
Geographical
Coverage
Technology
Coverage
Precision of
the Data
Completeness
of the Data
Yole Develop.
4
5
4
5
5
OSRAM input
2
5
3
5
5
DEFRA LCA
2
4
3
5
4
In terms of the time-related coverage, the OSRAM life-cycle assessment (OSRAM, 2009) and the
DEFRA study (DEFRA, 2009) were both published in 2009 and therefore represent LED technology
from 2008 and 2009. These two studies are given a relatively low ranking on a time-scale due to the very
rapid evolution of LED technology, which is experiencing significant change in both the manufacturing
processes and the performance of the technology itself. The Yole research that was shared with this team,
on the other hand, represents InGaN white-light LED production from the 2010 – 2011 time period, so it
represents technologies and processes that are closer to those used in 2012.
In terms of geographical coverage, all of the studies scored relatively high. Yole’s research is modeling
the manufacturing processes of one of the major LED manufacturers in the world, therefore this is clearly
given the highest score for global coverage. OSRAM retails product in over 150 countries around the
world, so their LCA is about a technology that is global in nature, even if it has only been introduced in a
few markets initially. The DEFRA study is given a slightly lower score because its focus was the UK
market, drawing examples of products – as much as possible – from the UK. Many of these same or
similar products are available elsewhere in the world, however the focus is on the UK and so the
geographical coverage score is a 4.
In terms of technology coverage, the scores reflect the age of each of the data sources as well as the
content contained therein. The Yole research is reflective of a recent manufacturing process for a high-
volume, globally available LED technology. However it only characterizes the process and performance
of this one manufacturer, and therefore isn’t representative of all the technologies and approaches
followed in the market. For this reason, the study is given a 4. For the OSRAM and DEFRA studies, these
are both slightly dated, so the technologies being discussed and characterized in these reports are slightly
out of date on a technological basis, resulting in a score of 3 for both.
In terms of the precision of the data, each study is given a 5 because they are all considered to be
thoroughly researched, documented and peer-reviewed. The presentation in each case is clear and concise,
and is easy to analyze and adapt to this work. Hence they are all given the top score for this data quality
criterion.
Finally, on completeness of the data, the Yole research is given top marks again because the study offers a
highly detailed and rigorous process analysis. The research team at Yole Développement includes several
process engineers, solid-state scientists and researchers with industry experience. Given that level of
Page 62
technical expertise in-house, we find that the product of their research institute to be complete for the
purposes of this study. Similarly, the OSRAM study is given top marks because it is the first LCA that we
are aware of that was published by one of the global manufacturers of LEDs. In preparing their work,
OSRAM drew upon a wide range of expertise from within their company, and ensured that the detail
included in their resulting report was highly rigorous and accurate. OSRAM confirms this fact by
demonstrating that this study was peer-reviewed by three independent experts who are familiar with LCA
science. The DEFRA report is given 4 out of 5 because it relies on secondary sources of information for
some of the lamps analyzed which are not complete. This became clear, for example, studying the
baseline incandescent lamp and CFL which are cross-referenced to other studies.
7.4.1 Comparison of Ecoinvent LED with DOE LED Impact Estimates
As discussed earlier in this report, the Ecoinvent database version 2.2 already contains an entry for an
LED. The Ecoinvent LED record covers raw material input and production of 5 millimeter LEDs for
hole-through mounting technology. The LEDs modeled in the Ecoinvent database are commonly used in
the information and communication technology industries and have a typical weight of 0.35 grams per
unit. The impact assessment takes into account average diode production technology, including the diode
wafer production (i.e., cleaning, masking, etching, doping, oxidizing, and metal deposition) and the final
assembly of the diode (wafer sawing, die bonding, molding, trimming and forming). While this is a very
good record for an indicator LED, it does not represent a high-brightness LED and also is based on LED
manufacturing technology from 2007 and 2008, rather than the equipment being used today.
In Chapter 5 of this report, the authors present their characterization of the LED manufacturing process.
LED manufacturing is an interim step in the production of an LED lamp which is ultimately what this
study is investigating. However, for the purposes of understanding how much LED technology has
improved and/or is different relative to the Ecoinvent LED that already exists in database version 2.2, the
authors prepared a comparison of the environmental impacts associated with these two LEDs. Due to the
fact that one LED is a 5 millimeter indicator lamp and the other is a high-brightness LED used in general
illumination applications, the impacts need to be normalized for light output from the device. The
indicator lamp was found to have a light output of 4 lumens, whereas the high-brightness LED was found
to have a light output of 70 lumens (Philips, 2012).
The following table presents the comparison between the Ecoinvent LED and the InGaN LED
manufactured for use in the Philips EnduraLED lamp. The table shows the significant reduction in the
environmental impacts on a per-lumen basis that have been achieved between the 2007 Ecoinvent
assessment and the 2011 technology that was assessed in this model. Overall, the average reduction in
impact is 94.5%.
Page 63
Table 7-10. Comparison of Ecoinvent LED and this Study’s LED Manufacturing Impacts
Ecoinvent Indicator
Units
Ecoinvent LED*
(2007)
DOE LED
(2011)
Reduced
Impact %
Global Warming Potential
kg CO2-Eq
0.0268
0.00155
92.3%
Acidification Potential
kg SO2-Eq
0.000131
0.0000105
89.3%
Photochemical Ozone
Creation Potential
kg formed ozone
0.00000318
0.000000105
95.6%
Ozone Depleting Potential
kg CFC-11-Eq
2.33E-09
2.86E-11
98.4%
Human Toxicity Potential
kg 1,4-DCB-Eq
0.00613
0.000192
95.8%
Freshwater Aquatic
Ecotoxicity Potential
kg 1,4-DCB-Eq
0.000129
0.00000402
95.9%
Marine Aquatic Ecotoxicity
Potential
kg 1,4-DCB-Eq
0.00317
0.0000829
96.5%
Eutrophication Potential
kg PO4-Eq
0.0000841
0.00000193
96.9%
Land Use
m2a
0.000571
0.0000446
89.6%
Ecosystem Damage Potential
points
0.000444
0.0000352
89.4%
Terrestrial Ecotoxicity
Potential
kg 1,4-DCB-Eq
0.00000535
0.000000213
94.7%
Abiotic Resource Depletion
kg antimony-Eq
0.000199
0.0000084
94.4%
Non-Hazardous Waste
Landfilled
kg waste
0.00139
0.0000863
91.7%
Radioactive Waste Landfilled
kg waste
0.00000233
2.64E-08
98.5%
Hazardous Waste Landfilled
kg waste
0.00000065
9.14E-09
98.1%
Average:
94.5%
* The Ecoinvent database unique ID for the “light emitting diode, LED”, at plant is 7077.
Thus, on a lumen output basis, it would appear that high-brightness LEDs manufactured in 2011 are
significantly less harmful for the environment than the 5mm indicator LEDs that were produced in 2007.
Page 64
8 Critical Review
Input solicited from several lighting experts and manufacturers during the course of the project has
provided the critical peer review section of the LCA. This report will be circulated in draft form to allow
additional comments from industry prior to finalizing the study results.
Early review by manufacturers confirmed that the assumptions in this report are realistic, and they
indicated that many of the manufacturing processes are already more efficient than those documented in
this report. Other reviewers indicated that the chemical and energy use documented in this report for the
MOCVD process appears to be reasonable.
Page 65
9 Recommendations
This report and the Part 1 study (DOE 2012a) together provide a full summary of LED LCA work to date.
This analysis documents the manufacturing process in a publicly-accessible medium for external review
and comment, which will enable the LCA and lighting research communities to continue refining the
research.
Several recommendations for future work have been highlighted by the study:
1. Work with manufacturers to reduce the size of aluminum heat sinks and/or find alternative
materials and configurations to reduce the mass. The manufacturing of aluminum heat sinks
contribute significantly to upstream waste and energy consumption. Manufacturers are testing a
variety of new techniques to improve heat transfer, which may result in more environmentally
friendly products with smaller heat sinks.
2. Work with manufacturers to meet the DOE targets for efficacy and performance that will make
LED lighting solutions dramatically better than CFLs for the full life cycle environmental
impacts. This may include, for example, creating the “L-Prize Mark II” to further encourage
innovation and improvement in the efficacy of LED lamps, as the energy-in-use phase has proven
to have the most significant environmental impact of all those analyzed.
3. Encourage academic and industry studies of and programs for recycling to improve end of life
options for LED products. The heat sink represents a significant cost opportunity for recycling
programs.
4. Revisit the manufacturing process documented in this report periodically to account for
improvements to the process, which may further reduce the environmental impacts of LED
systems.
5. Encourage Ecoinvent to establish a new category of ‘high brightness LED’ for the Ecoinvent
database which reflects 2012 LED manufacturing technology as opposed to the 2007 indicator
light LED that is currently in the database.
The last part of this study (Part 3) will provide additional insight about the disposal of the products by
testing LEDs for disposal thresholds. This part of the study will provide a useful “check” on the actual
environmental impact of one LED lamp and compare it to the benchmark provided by EPA and other
regulatory groups.
Page 66
10 APPENDIX A: Sensitivity Analysis
This section provides an overview of an analysis that was conducted to quantify the sensitivity of the
results to possible changes in the assumptions or estimates underpinning the model. One option for
dealing with this uncertainty is simply to make an estimate of the unknown parameters. This is a
pragmatic approach to arriving at an answer, but creates uncertainty about the reliability of the results. A
sensitivity analysis aims to explore the sensitivity of the results and conclusions to these underlying
assumptions, and thereby provide comment on the confidence in the results.
A Monte Carlo analysis is a useful tool for checking confidence in estimates and assumed values. With
this tool, the user stipulates which parameters will be variables, and specifies the distribution for each of
those parameters. The Monte Carlo analysis then performs multiple calculations, each time randomly
generating a value from within the defined range and using it to generate results from a run of the model.
The final output of a Monte Carlo analysis is a distribution of results instead of a single point result. By
plotting histograms of the distributions for the different lamp types analyzed, it is possible to determine,
by the amount of overlap, a level of confidence in the results.
A Monte Carlo sensitivity analysis was run on the LCA model varying the lifetime of each of the lamps,
the efficacy and the percentage recycling at end of life. The calculations were performed in the Microsoft
Excel workbook that had been created, using the Oracle Crystal Ball software plug-in. Table A-1 presents
the parameters chosen for the simulation. All were modeled using a normal distribution, and the means
and standard deviations (SD) of the distributions are also shown. A total of 10,000 runs of the model were
conducted for this sensitivity analysis.
Table A-1. Parameters of Normal Distributions Used in the Monte Carlo Sensitivity Analysis
Incandescent
Mean
Standard Deviation
Units
Efficacy
15
1
lumens/watt
Lifetime
1500
100
hours
Recycling Lamp
0.1
0.025
percent recycled
Recycling Packaging
0.3
0.05
percent recycled
Compact Fluorescent Lamp
Mean
Standard Deviation
Units
Efficacy
55
5
lumens/watt
Lifetime
8000
1000
hours
Recycling Lamp
0.2
0.025
percent recycled
Recycling Packaging
0.3
0.05
percent recycled
Light Emitting Diode 2012
Mean
Standard Deviation
Units
Efficacy
65
7
lumens/watt
Lifetime
25000
5000
hours
Recycling Lamp
0.2
0.025
percent recycled
Recycling Packaging
0.3
0.05
percent recycled
Light Emitting Diode 2017
Mean
Standard Deviation
Units
Efficacy
134
15
lumens/watt
Lifetime
40000
5000
hours
Recycling Lamp
0.2
0.025
percent recycled
Recycling Packaging
0.5
0.1
percent recycled
Page 67
Results
The general form of the results is depicted in Figure A-1, which shows the predicted future global
warming potential of the four lamps analyzed in this report. The plot is based on 10,000 runs of the model
varying the input assumptions shown in Table A-1. From this graph, it is clear that the incandescent lamp
has the highest impact for global warming potential with a mean at 51 kg CO2-equivalents per million
lumen hours and a standard deviation of 3.5 kilograms. The CFL has a mean of 15.2 kg CO2-equivalents
per million lumen hours with a much tighter standard deviation of 1.4 kilograms. The LED 2012 lamp has
virtually the same shape as the CFL and the same standard deviation, but its mean has shifted lower to
12.5 kg CO2-equivalents. Finally, the LED 2017 lamp has the tightest distribution of results, with a mean
of 5.7 kg and a standard deviation of only 0.6 kg.
This finding strengthens the overall outcome of this study, providing more assurance that varying the
inputs to the degree they are in Table A-1 does not change the overall finding and prioritization of
impacts for this environmental indicator. And, while this graph only presents the impacts in terms of
global warming potential, the outcome is similar for the other 14 indicators.
Figure A-1 Scatter Plot of Results for Monte Carlo Analysis of Global Warming Potential
Figure A-2 presents the scatter plot of results for the Monte Carlo analysis of Hazardous Waste Landfill.
This is the environmental indicator which found that LED lamps in 2012 had slightly more impact than
CFLs (see Figure 7-6). Using the same range of input variables given in Table A-1, the following graph
was prepared for the Hazardous Waste Landfill indicator.
0
100
200
300
400
500
600
700
800
010 20 30 40 50 60 70 80
Count (out of 10,000 runs)
Global Warming Potential (kg CO2-Eq / megalumen-hour)
CFL
LED 2012
Incandescent
LED 2017
Page 68
Figure A-2 Scatter Plot of Results for Monte Carlo Analysis of Hazardous Waste Potential
The shape and overlapping nature of the two graphs are slightly different. The LED has a mean of 0.41
grams of hazardous waste per megalumen-hour with a standard deviation of 0.06 grams. The CFL has a
mean of 0.38 grams of hazardous waste with a standard deviation of just 0.04 grams. The mean values of
the two lamp types are extremely close and the area described under the two scatter plots of results is very
similar. To get a more detailed view of these two lamps, we remove the incandescent lamp and the LED
2017 lamp, as shown in Figure A-3.
0
50
100
150
200
250
00.0005 0.001 0.0015 0.002
Count (out of 10,000 runs)
Hazardous Waste Landfill (kg hazardous waste / megalumen-hour)
CFL
LED 2012
Incandescent
LED 2017
Page 69
Figure A-3 Scatter Plot of Results for CFL and LED 2012 of Hazardous Waste Potential
In Figure A-3, by zooming in on this section of the X-axis and removing the other lamp types from the
plot, it becomes easier to focus on a comparison between these two distributions. There is reasonably
good overlap to the left of the two plots, which represents those lamps having lower hazardous waste
landfill impacts. The mean values for these two scatter plots are different, but the CFL lamp is only 7%
lower than the LED 2012. The reason for this difference is because of the right hand part of the two
curves, where the LED lamp has a longer tail stretching out to the right. Referring back to Figure A-2, it
is important to note that the LED lamp in 2017 has significantly lower hazardous waste landfill impact
when compared to CFLs. This is due to the projected improvements in efficacy and the associated
reduction in the mass of the aluminum heat sinks used in the 2017 LED lamp design.
In conclusion, the Monte Carlo sensitivity analysis shows that the incandescent lamp has, by a
considerable margin, the largest environmental impact and thus represents the least preferred lighting
option. Due to the great impact associated with energy-in use, changing to a more efficient lamp will
reduce impacts, with LED lamps in 2012 being a better option on a LCA basis than CFLs. LED lamps in
2017 represent a significantly better lighting option, with much lower environmental impacts.
0
20
40
60
80
100
120
140
160
0.0002 0.0003 0.0004 0.0005 0.0006 0.0007
Count (out of 10,000 runs)
Hazardous Waste Landfill (kg hazardous waste / megalumen-hour)
CFL
LED 2012
Page 70
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