An environmental and economic analysis of the wood-pellet chain: two case studies in Southern Italy

Abstract

Purpose Wood pellet heating systems are considered as an essential component of European plans to reduce greenhouse gas (GHG) emissions. The goal of this analysis was to estimate and compare the environmental impacts and the costs of the production of packed wood pellets. Two pellet production systems, using roundwood logs (case 1) and mainly sawdust (case 2), have been analysed in 2015 in Basilicata region
(Southern Italy).
Methods A life cycle assessment (LCA) analysis was applied to calculate the environmental impact indicators of each system, whilst a life cycle cost (LCC) analysis was implemented to evaluate the pellets’ cost production. Hence, the functional unit chosen was 1 t of produced pellets. The system boundaries considered for the purpose of the current investigation were from the tree felling to the pellet packaging. In particular,
the following activitieswere considered: motor-manual felling and delimbing with a chainsaw, timber yarding with a tractor along the forest track, loading and transportation of the logs to the collection point, transportation of timber to the factories for a distance of 35 km, pellet production and pellet packaging in low-density polyethylene bags with a total weight of 15 kg bag−1.
Results and discussion The production of 1 t of pellets emitted about 83 kg of CO2eq in case 1 and 38 kg in case 2. In addition, 2.7 kg of SO2eq and 0.005 kg of PO3 4-eq were produced in case 1 and 1.4 kg of SO2eq and 0.002 kg of PO3 4-eq in case 2. Mineral extraction was equal to 0.9 MJ surplus energy in both cases. Case 1 led to higher environmental impacts (about 50% more), essentially for the operation of pelletisation, and in particular for the higher consumption of electricity that characterised it, whereas the production
costs were 172 and 113 € t−1 in case 1 and case 2, respectively.
In both study cases, consumption costs (costs for raw material,electricity consumption, fuel usage) were the most important cost items.
Conclusions Our studies highlight how, in both cases, the operations carried out in the forest produced the minor part of the environmental impact but, at the same time, were the most expensive operations. Further, our studies show how mixing lumbering by-products (sawdust) and forest management products (lumbers) can be an efficient solution to reduce both manufacturing costs and environmental impacts to produce wood pellets.

Full text

ORIGINALIEN
An environmental and economic analysis of the wood-pellet chain:
two case studies in Southern Italy
Maria Pergola
1
&Amalia Gialdini
2
&Giuseppe Celano
3
&Marina Basile
2
&
Donatella Caniani
4
&Mario Cozzi
2
&Tiziana Gentilesca
2
&Ignazio M. Mancini
4
&
Vittoria Pastore
1
&Severino Romano
2
&Gennaro Ventura
2
&Francesco Ripullone
2
Received: 5 December 2016 / Accepted: 7 July 2017
#Springer-Verlag GmbH Germany 2017
Abstract
Purpose Wood pellet heating systems are considered as an
essential component of European plans to reduce greenhouse
gas (GHG) emissions. The goal of this analysis was to esti-
mate and compare the environmental impacts and the costs of
the production of packed wood pellets. Two pellet production
systems, using roundwood logs (case 1) and mainly sawdust
(case 2), have been analysed in 2015 in Basilicata region
(Southern Italy).
Methods A life cycle assessment (LCA) analysis was applied
to calculate the environmental impact indicators of each sys-
tem, whilst a life cycle cost (LCC) analysis was implemented
to evaluate the pellets’cost production. Hence, the functional
unit chosen was 1 t of produced pellets. The system bound-
aries considered for the purpose of the current investigation
were from the tree felling to the pellet packaging. In particular,
the following activities were considered: motor-manual felling
and delimbing with a chainsaw, timber yarding with a tractor
along the forest track, loading and transportation of the logs to
the collection point, transportation of timber to the factories
for a distance of 35 km, pellet production and pellet packaging
in low-density polyethylene bags with a total weight of
15 kg bag
−1
.
Results and discussion The production of 1 t of pellets emit-
ted about 83 kg of CO
2
eq in case 1 and 38 kg in case 2. In
addition, 2.7 kg of SO
2
eq and 0.005 kg of PO
3
4
-eq were
produced in case 1 and 1.4 kg of SO
2
eq and 0.002 kg of
PO
3
4
-eq in case 2. Mineral extraction was equal to 0.9 MJ
surplus energy in both cases. Case 1 led to higher environ-
mental impacts (about 50% more), essentially for the opera-
tion of pelletisation, and in particular for the higher consump-
tion of electricity that characterised it, whereas the production
costs were 172 and 113 €t
−1
in case 1 and case 2, respectively.
In both study cases, consumption costs (costs for raw material,
electricity consumption, fuel usage) were the most important
cost items.
Conclusions Our studies highlight how, in both cases, the
operations carried out in the forest produced the minor part
of the environmental impact but, at the same time, were the
most expensive operations. Further, our studies show how
mixing lumbering by-products (sawdust) and forest manage-
ment products (lumbers) can be an efficient solution to reduce
both manufacturing costs and environmental impacts to pro-
duce wood pellets.
Keywords Bio-economy .Climate change .LCA .LCC .
Sustainable forestry .Woody biomass residues
1 Introduction
Climate change is an environmental issue widely recognised
by the international scientific community. The European
Union has set itself two important and ambitious targets in
the environmental and energy policy, to be achieved by
Responsible editor: Jörg Schweinle
*Francesco Ripullone
francesco.ripullone@unibas.it
1
Ages s.r.l.s-Spin-off Accademico, Università degli Studi della
Basilicata, Viale dell’Ateneo Lucano, 10, 85100 Potenza, Italy
2
Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali,
Università degli Studi della Basilicata, viale dell’Ateneo Lucano, 10,
85100 Potenza, Italy
3
Dipartimento di Farmacia (DIFARMA), Università degli Studi di
Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
4
Scuola di Ingegneria, Università degli Studi della Basilicata, viale
dell’Ateneo Lucano, 10, 85100 Potenza, Italy
Int J Life Cycle Assess
DOI 10.1007/s11367-017-1374-z

2020 (COM 2008): a 20% reduction of greenhouse gas
(GHG) emissions and 20% of Europe’s energy produced by
renewable sources. In addition, 42% of total renewable energy
is expected to be obtained from biomass, including electricity,
heating and cooling (EU 2009). A contribution to the Europe
2020 strategy goals may come from a modern bio-economy
based on the sustainability in the extraction of biomass raw
material, the efficiency in biomass use and the economies of
scales in biomass mobilisation (Scarlat et al. 2015). The use of
wood biomass for energy production and the use of renewable
products (e.g. pellets) are probably the most important contri-
butions of forest ecosystems to the reduction of GHG concen-
tration in the atmosphere, as required by the Kyoto Protocol
(Magelli et al. 2009; Murphy et al. 2015; Alivernini et al.
2016).
According to Laschi et al. (2016), Italy is the third most
important country in Europe in terms of pellet production and
has the largest European market in bagged high-quality pellets
for domestic use (González-García et al. 2009; Hiegl and
Janssen 2009; Sikkema et al. 2011). Within the Italian territo-
ry, Basilicata (Southern Italy) is one of the regions with the
highest coefficient of forest cover at the national level with
almost one third of its land area covered by forests
(360,000 ha). Despite their potential, these forests are really
far from their optimal use. Consequentially, the forestry sector,
if well managed, could be one of the sectors with higher ter-
ritorial enhancement capabilities both in terms of employment
and activation of new enterprises. One of the aims of the
current regional forest management is the realisation of a
woodland-lumber chain, in which the primary and secondary
wood products are processed in order to obtain firewood. In
this context, the activities of the sector companies would be
more and more oriented towards the realisation of very short
supply chain products (at 0 km), in order to have lower costs
and impacts on the environment (less pollution from products
transport) and to use resources and local manpower (Bidini
et al. 2006).
Hence, there is a need to enhance the communications of
the environmental performances of these products to the final
consumer through, e.g. the carbon footprint. This labelling
communicates one important aspect of the sustainability of a
product through the indication of the amount of carbon diox-
ide emitted during its realisation (Andrićet al. 2015). This
system, on the one hand, helps the consumers to guide their
purchasing decisions towards high environmental quality
products and services and, on the other hand, encourages the
producers to act in the production processes with more eco-
efficient technical and organisational solutions. An interna-
tionally recognised methodology that evaluates the entire life
cycle of a product is the life cycle assessment (LCA), which
allows to identify, quantify and environmentally analyse all
inputs and outputs involved in production, use and disposal of
a product (Baumann and Tillman 2004). In the last few years,
LCA together with life cycle costing (LCC) has been increas-
ingly used inorder to evaluate the environmental and econom-
ic performances of products, processes and systems.
In this context, the aim of the present study is to evaluate
the environmental and economic profile of the wood-pellet
chain in Basilicata region following a life cycle approach
and considering the forest management for raw material sup-
ply. Considering the scarcity of studies on wood pellets and on
the contribution of logging operations to the global environ-
mental problem, this study would give a contribution to these
failings.
2 A brief review of the specialised scientific literature
In literature, several studies have analysed the environmental
impact of the manufacturing of pellets (Magelli et al. 2009;
Fantozzi and Buratti 2010; Adams et al. 2015;Monteleone
et al. 2015; Röder et al. 2015; Kylili et al. 2016;Laschietal.
2016). In some cases, this was compared to other types of
biomass (Upham and Smith 2014; Dinca et al. 2014;Benetto
et al. 2015;Murphyetal.2015) or to traditional fuels (Pa et al.
2011; Sjolie and Solberg 2011; McNamee et al. 2016).
Other studies have evaluated the economic sustainability of
pellet production, by analysing the manufacturing process in
individual case studies (Uasuf and Becker 2011;Kebedeetal.
2013; Monarca et al. 2011;Kangetal.2013; Hoefnagels et al.
2014;Shahrukhetal.2016) or by comparing manufacturing
systems in different countries (Thek and Obernberger 2004;
Trømborg et al. 2013).
Only few studies (Sikkema et al. 2011;SultanaandKumar
2012; Tabata and Okuda 2012;Paetal.2013; Nishiguchi and
Tab ata 2016) have faced up to the economic and environmen-
tal sustainability of pellet processing, and few others (Magelli
et al. 2009;Paetal.2012; Paolotti et al. 2015)havemadean
economic and environmental analysis of their transport from
the production areas to the consumer areas.
3 The Italian wood pellet sector
Italy, with its 80 producers, is Europe’s third largest pellet
producer (0.77 million t) (Sikkema et al. 2011), and 70% of
the national supply is located in Northern Italy (ETA
Florence 2016). In Italy, pellets are used almost exclusively
for domestic, commercial enterprise and institution heating
(Sikkema et al. 2011). In 2012, Italian wood pellet con-
sumption reached 1.9 million t and continues to increase
at a rate of 400,000 t per year, with only a small fraction
domestically produced. From a peak of 750,000 t in 2007,
Italy now produces 550,000 t annually, 29% of its 2011
consumption. Consequently, Italy depends to a very large
Int J Life Cycle Assess

extent on the import of wood pellets: mainly from Austria
(32%) and Eastern Europe (26%) (Ligabue 2015).
In Basilicata region, in relation to the availability of raw
materials (360,000 ha of forests), the use of wood as a
heating source is widely spreading and the wood supply
chains have a large potential development. In the last
5 years, numerous projects have been implemented in the
region to promote the development and diversification of
forest products, particularly in relation to energy use. At the
same time, however, the expectations to enhance the forest-
ry sector have been disappointed for unfavourable conjunc-
tures related to the local forest-wood market. These latter
can be summarised in: (1) the scarcity of companies with
an operational capability such as to continuously support
the wood-pellet chain; (2) the absence of cooperativism
initiatives from small companies (units with less than 5
workers and with an average operational capability of
30 ha/year of logged forest areas); and (3) the limited
mechanisation and efficiency of forest logging, due to the
irregular regional morphology, with the addition of the
strong prevalence of public ownership, with the resulting
administrative and management burdens (Lam et al. 2011).
The expansion of the pellet market since 2000, accentu-
ated between 2008 and 2010 due to the massive replace-
ment of traditional boilers in favour of those powered by
pellets, and the growth of the importers and retailers of
pellets on the regional territory, has allowed the local en-
trepreneurs to move towards innovative and cooperative
actions. A form of diversification undertaken by the forest
companies to try to adapt to market changes includes the
provision of raw material for the production of wood chips
to processing companies.
An additional strategy implemented by some forest com-
panies in Basilicata region is represented by attempts to
produce pellets from the local forest, delegating, however,
some processing steps outside the region with a high inci-
dence of transport costs of raw materials and expenses due
to the commercialisation of the processed products
(Sacchelli et al. 2013). Ultimately, however, company ini-
tiatives have arisen with the specific purpose to produce
pellets. Hence, there were no real diversification processes
or conversions of local logging companies. Therefore, the
decline of traditional companies, characterised mainly by
scarce generational turnover, is still in progress.
The four official pellet plants currently present in
Basilicata region are characterised by low yields and small
catchment areas. At the same time, the inadequate financial
envelope does not allow them to sustain the realisation
costs of medium-large structures. In addition, this would
also require an upstream supply system capable of
supporting the long-term demands of the plants. In this
framework, the current state of the supply is not guaranteed
by the forest governance system, especially for public ones.
4 Materials and methods
4.1 Description of the study area and the analysed systems
The analysis was performed in 2015, and two case studies were
investigated. The two analysed factories are located in Tito
(Potenza province, Basilicata region, Italy). The first enterprise
(case 1) produced pellets from roundwood beech logs (Fagus
sylvatica L.) from regional forests. In this case, after the motor-
manual felling and delimbing with a chainsaw, timber was
yarded with a tractor along the forest track and transported to
the factories for chipping and pelletisation.
The second enterprise(case 2)was a sawmillproducingsemi-
finished, wooden packing cases and railway sleepers in oak
(Quercus cerris L. and Quercus pubescens Willd.). Ecological
pellets were mainly produced from the sawdust as co-products.
The transformation process was the same asin case 1, but in this
case, there was no chipping operation but the manufacture of
semi-finished, the mixing of the sawdust produced with bought
wood chips and pelletisation to produce pellets.
The wood utilised by the analysed factories belongs mainly
to a regional mixed high forest stand (Abriola, Basilicata
Region 40° 29′42″N, 15° 54′28″E). Here, the distribution
of beech consists of pure and mixed stands with oak, at the
lowest altitude, and occasionally silver fir (Abies alba Mill.)
and douglas fir (Pseudotsuga menziesii Mirb.) (stands artifi-
cially planted during the 1960s).
4.2 Environmental analysis
The environmental analysis was carried out according to LCA
methodology from ISO 14040 and 14044 standards (ISO
14040: 2006; ISO 14044: 2006). TheSimaPro v. 8.04 software
(PRé, various authors 2015) was used to determine the envi-
ronmental impacts of the examined systems.
4.2.1 Goal definition, functional unit and system boundaries
The goal of this analysis was to estimate and compare the
environmental impacts of the production of packed wood pel-
lets by two different systems (logs and sawdust). The results of
this analysis can be useful, on the one hand, for forest harvest-
ing enterprises, sawmills, technicians and local politicians to
build the chain of custody for forest products and, on the other
hand, for consumers to trace the chain of these products to a
definite territory of origin. Therefore, the functional unit cho-
sen, namely the reference unit that expresses the function of the
system in quantitative terms and provides the reference to
which all data in the assessment are normalised, was 1 t of
produced pellets.
The system boundaries considered for the purpose of the
current investigation were from the tree felling to the pellet
packaging (Fig. 1). In particular, the following activities were
Int J Life Cycle Assess

considered: motor-manual felling and delimbing with a chain-
saw; timber yarding with a tractor along the forest track; load-
ing and transportation of the logs to the collection point, trans-
portation of timber to the factories for a distance of 35 km,
pellet production (chipping and pelletisation for case 1, saw-
dust production from semi-finished products processing and
pelletisation of the sawdust for case 2) and pellet packaging
in LDPE (low-density polyethylene) bags with a total weight
of 15 kg bag
−1
. Therefore, the system boundaries encompassed
impacts associated with fuel usage and electricity consumed in
the various operations. Referring to machines, only those used
in forestry were considered; in particular, manufacturing,
maintenance and final disposal were taken into account.
In case 2, the production of the pellets was a co-product of
the enterprise. Indeed, it was a sawmill producing mainly
semi-finished, wooden packing cases and railway sleepers in
oak. Allocation, or the division, of the environmental impacts
between the products and co-products has been performed on
the quantity produced. In particular, pellet production repre-
sented 40% of the total production of case 2, so pellets give
40% of the environmental impacts.
4.2.2 Data collection and life cycle inventory analysis
The inventory of the data associated to the studied systems
was collected in situ, using a data collection sheet. Information
on the quantities of machinery, fuel, electricity and other items
used was gathered. All items and all machinery used in the
examined systems are reported in Tables 1and 2.
In the present study, the quantity of materials and the
amount of electricity, fuel and lubricants consumed for each
operation (felling, yarding, loading and transportation, pellet
production and packaging) have been measured and used in
the analysis. Emissions from input production (diesel, lubri-
cants, electricity, LDPE) and those from the construction of
the vehicles were derived from the ECOINVENT 3 database
(Moreno Ruiz et al. 2013).
Referring to the electricity, the dataset describes the trans-
formation from medium to low voltage as well as the distri-
bution of electricity at low voltage. In particular, it encom-
passes the electricity production in Italy and from imports
and the transmission network. Also, electricity losses during
low-voltage transmission and transformation from medium
voltage were accounted by Moreno Ruiz et al. (2013). The
fuel and lubricant consumption model considered the trans-
portation of products from the refinery to the end user. The
inventory ofvehicles and machines usedin the forest took into
account the use of resources and the amount of emissions
during their production, use, maintenance, repair and final
disposal. The machines used for the pellet production (chipper
and pelletiser machines) were not considered in the present
analyses for the lack of appropriate and specific information
(constructive features and weights).
4.2.3 Life cycle impact assessment
The impact assessment was performed following the IMPACT
2002+ (acronym of IMPact Assessment of Chemical Toxics)
method, a combination of four methods: IMPACT 2002
(Pennington et al. 2005), Eco-indicator 99 (Goedkoop and
Spriensma 2000), CML (Guinée et al. 2002)andIPCC
(Jolliet et al. 2003). The following six impact categories were
evaluated according to the selected method: ozone layer deple-
tion (OLD), photochemical oxidation (PO), acidification (A),
eutrophication (E), global warming (GW) and mineral extrac-
tion (ME). As suggested by the authors of IMPACT 2002+
Felling
and
delimbing
Ya rd i n g
Loadi ng
and
Transportation to pellet plant
Pelletisation
Packaging
Machinery, materials, energy, fuels and lubricants production
and consumption
Emissions to air, water and soil
Case 2:
semi-finished processing and
sawdust production
Case 1:
timber chipping
Mixing sawdust and
wood chips
Fig. 1 System boundaries for the
case studies analysed
Int J Life Cycle Assess

method, normalised scores were analysed at damage level
(Humbert et al. 2012). The normalisation analyses the
respective share of each impact to the overall damage of the
considered categories, and it is performed as the ratio between
the impact (at damage categories) and the respective normal-
isation factors. These latter represent the total impact of the
specific category divided by the total European population.
The total impact of the specific category is the sum of the
products among all the European emissions plus resource con-
sumption in 2000 and the respective damage factors.
In the present study, after classification, characterisation
and normalisation, we also added the weighting phase, an
optional step in life cycle impact assessment (LCIA). In par-
ticular, weighting entails multiplying the normalised results of
each of the impact categories with a weighting factor that
expresses the relative importance of the impact category.
Thanks to weighting, results all have the same unit (mPt)
and can be added up to create one single score for the envi-
ronmental impact of a product or scenario.
4.3 Cost production analysis
The production cost of 1 t of pellets was analysed according to
the life cycle costing (LCC) methodology, a method utilised to
calculate the total cost throughout the product’s life including
acquisition, installation, operation, maintenance, refurbish-
ment and disposal (Bai 2009). LCC is a complementary tool,
which provides an economic analysis of the operations com-
posing the supply chain of a product or service (Brandão et al.
2010). LCC does not have a standardisation framework to
follow. However, the life cycle approach and methodologies
from ISO 14040 for LCA can be applied to these other aspects
(ISO 2006). In order to join LCC with LCA, in this study, the
analysis was conducted with the same system boundaries de-
scribed for LCA. The life cycle inventory of the LCA was an
excellent basis for identifying and allocating all costs in an
efficient manner.
According to Thek and Obernberger (2004), for each case,
the economic evaluation of the total pellet processing was
done taking into account the following costs: capital and
maintenance costs (investment costs of all units of the pellet
production process as well as of construction, offices and data
processing, market introduction and planning as well as the
utilisation period and maintenance costs of all units and facil-
ities), consumption costs (costs for raw material, electricity
consumption, fuel usage), operating costs (personnel costs)
and other costs (insurance rates, overall dues, taxes and ad-
ministration costs).
In order to calculate the different costs, data on capital
equipment expenditures were taken from literature (Thek
and Obernberger 2004; Monarca et al. 2011) for lack of
this information; consumption and operating costs were col-
lected in situ during 2015; whilst the Bother costs^were
calculated as a percentage of the overall investment costs
(2%) (Uasuf and Becker 2011).
Tabl e 1 Items used in the examined case studies. Values per ton of the
pellet. In case 1, pellets are produced from roundwood logs; in case 2,
pellets are produced mainly from sawdust
Case 1 Case 2
Felling
Lumber (t) 2.00
Machinery (h) 0.88
Diesel and lubricants (kg) 1.85
Human labour (h) 0.88
Load
Machinery (h) 0.17
Diesel and lubricants (kg) 0.82
Human labour (h) 0.17
Transportation
Machinery (h) 0.13
Diesel and lubricants (kg) 2.01
Human labour (h) 0.11
Timber chipping
Machinery (h) 0.20 –
Diesel and lubricants (kg) 2.49 –
Human labour (h) 0.03 –
Sawdust production from
semi-finished processing
Machinery (h) –0.08
Diesel and lubricants (kg) –0.03
Electricity (kWh) –2.00
Human labour (h) –0.01
Pelletisation
Machinery (h) 3.93 1.02
Diesel and lubricants (kg) –2.45
Electricity (kWh) 83.00 18.00
Wood chips (used as fuel) (kg) –321.00
Human labour (h) 0.05 0.16
Packaging
LDPE bags (no.) 67.00 67.00
Human labour (h) 0.16 0.16
Tabl e 2 Machinery considering in the analysis of the examined case
studies
Operation Machinery
Felling Chainsaw 455 Rancher II AutoTune
Load Tractor Same Explorer 80 CHD
Crane for tractor 60 NFG
Transportation Tractor Motransa FIAT 980 DT 12 1
Lorry Volvo/Straller 430
Chipping Chipper CIP2300 Motor IVECO N45 (TRIAL3)
Int J Life Cycle Assess

The raw material assumed for pellet production was beech
logs for case 1 and a mix of oak and beech sawdust for case 2.
The average raw material prices were recorded on the market-
place of Potenza province in 2015 (60 €/t for beech and oak
timber at the collection point). The personnel costs were
accounted as hourly labour, and tariffs were recorded as above
(9 €/h for specialised labour; 6 €/h for generic labour net of
taxes). The prices of the electricity consumption and diesel
fuel usage were 0.27 €/kWh and 0.8 €/l, respectively.
5 Results and discussion
5.1 Environmental impacts
Tab le 3shows the results on the life cycle impacts per ton of
pellets produced according to the study cases. The production
of 1 t of pellets mainly emitted:
&83 kg of CO
2
eq in case 1 and 38 kg in case 2, which is
mainly responsible for global warming;
&2.7 kg of SO
2
eq in case 1 and 1.4 kg in case 2, which
causes air acidification;
&0.005 kg of PO
3
4
-eq in case 1 and 0.002 kg in case 2,
which is responsible of eutrophication.
In addition, we also obtained mineral extraction, expressed
in megajoules surplus energy/kg extracted, equal to 0.9 both
in cases 1 and 2.
Referring to global warming potential (GWP), the only im-
pact category which can be compared with other studies, be-
cause no other results are available, was on average similar to
most of the data available in literature: i.e. 40 kg CO
2
eq t
−1
for
high-quality pellet production for domestic heating in the
Tuscany region (Laschi et al. 2016) and 87.19 kg CO
2
eq t
−1
for the wood pellet production in British Columbia (Magelli
et al. 2009), etc, whilst, in other cases, our values were slightly
higher: i.e. from 16 to 35 kg CO
2
eq t
−1
for the pelleting process
of olive husks using solar thermal collectors for heat production
and solar photovoltaics for electricity production in Cyprus
(Kylili et al. 2016). In some other cases, our values were much
lower: i.e. from 167 to 240 kg CO
2
eq t
−1
for conventional
pelleting process of olive husks in Cyprus (Kylili et al. 2016)
and from 100 to 1102.5 kg CO
2
eq t
−1
for the wood pellet
production in Ireland (Murphy et al. 2015). The differences
among our results and literature data could be due to several
factors: diverse system boundaries, inventory analysis, soft-
ware and method used for the impact characterisation.
The differences obtained between cases 1 and 2 (Fig. 2)
highlighted how case 1 led to higher environmental impacts,
and this was even more evident observing weighed data. It
was observed that pelletisation and packaging were operations
with more impact in case 1, representing 46 and 19% of the
total impact, respectively, followed by chipping (15%) and
transportation (13%). On the contrary, in case 2, packaging
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
2esaC1esaC
Case studies
mPt
Felling and yarding Load Transportation Chipping/Sawdust production Pelletisation Packaging
Fig. 2 Weighing of the impact
categories of the examined case
studies. White: felling and
yarding, green: load, red:
transportation, yellow: chipping/
sawdust production, blue:
pelletisation, blue green:
packaging
Tabl e 3 Life cycle impacts per ton of pellet from the two case studies.
In case 1, pellets are produced from roundwood logs; in case 2 pellets are
produced mainly from sawdust
Impact categories Unit t
−1
Case 1 Case 2
Acidification kg SO
2
eq 2.712 1.359
Eutrophication kg PO
4
P-lim 0.005 0.002
Global warming kg CO
2
eq 83.237 37.567
Mineral extraction MJ surplus 0.947 0.835
Ozone layer depletion kg CFC
−11
eq 0.00001 0.000002
Photochemical oxidation kg C
2
H
4
eq 0.060 0.041
Int J Life Cycle Assess

was the most impactful operation (36%), followed by trans-
portation (25%) and pelletisation (23%). Operations carried
out in the forest (felling and yarding) produced the minor part
of the impact (1% in case 1 and 2% in case 2). This latter result
wasinlinewithdatareportedbyLaschietal.(2016), who
showed that in the production of high-quality pellets for do-
mestic heating, the forest operations produced from 1 to less
than 10% of the impact depending on the category.
The highest environmental impacts of case 1 (about 50%
more) were essentially due to the operation of pelletisation and
in particular to the electricity consumed in this phase (83 ver-
sus 18 kWh). In case 2, the pellet plant was powered by elec-
tricity, also by wood chips and diesel fuel, making it more
sustainable (Table 3).
The electricity consumed during pelletisation caused main-
ly ME, OLD, eutrophication and GWP in both study cases.
The production of the LDPE bags for packaging operation
caused mainly PO, GWP and air acidification. Production
and consumption of fuel during transportation caused mainly
air acidification above all in case 2 (Fig. 3). Therefore, in both
study cases from the normalisation data (Fig. 4), the most
damage affected resource depletion and human health.
5.2 Pellet production costs
LCC was employed to compare the economic results of
two study cases in order to better evaluate the sustainability
of the pellet production in Basilicata region. In our exper-
imental conditions, the production costs of 1 t of pellets
were equal to 172 €in case 1 and about 113 €in case 2
(Table 4). Our findings were similar compared to the ones
reported in other studies. In particular, Thek and
Obernberger (2004) accounted for 90.7 €t
−1
pellets under
Austrian framework conditions. Specific wood pellet pro-
duction costs under Italian framework conditions (Umbria
region) were 191 €t
−1
pellets (Monarca et al. 2011). Wood
pellet production costs in Finland, Germany, Sweden, Norway
and the USA vary between 119 and 160 €t
−1
including do-
mestic transport (Trømborg et al. 2013). Sikkema et al. (2011)
compared production costs for pellet production in Sweden,
Italy and the Netherlands and found these costs ranging be-
tween 110 and 170 €t
−1
. Only Uasuf and Becker (2011)
showed relative lower costs, ranging from 35 to 47 €t
−1
of
wood pellets, under different framework conditions in
Northeast Argentina.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Case 1 Case 2 Case 1 Case 2 Case 1 Case 2 Case 1 Case 2 Case 1 Case 2 Case 1 Case 2
Acidification Eutrophication Global warming Mineral extraction Ozone layer
depletion
Photochemical
oxidation
Impact categories
Felling and yarding Load Transportation Chipping/Sawdust production Pelletisation Packaging
Fig. 3 Characterisation of the
impact categories of the examined
case studies. White: felling and
yarding, green: load, red:
transportation, yellow: chipping/
sawdust production, blue:
pelletisation, blue green:
packaging
0.0E+00
2.0E-03
4.0E-03
6.0E-03
8.0E-03
1.0E-02
1.2E-02
1.4E-02
Human health Ecosystem quality Climate change Resources
Damage categories
Case 1 Case 2
Fig. 4 Normalisation of the
damage categories of the
examined case studies. Green:
case 1, yellow: case 2
Int J Life Cycle Assess

In both of our study cases, consumption costs (costs for raw
material, electricity consumption, fuel usage, wood chips and
bags) were the most important cost items. Within these costs,
the acquisition of raw material (beech and oak logs) constitut-
ed the major cost, representing 70 and 64% of the total cost in
case 1 and case 2, respectively. These results were in good
agreement with Uasuf and Becker (2011), which showed that
raw material was the dominant cost factor in their four
analysed scenarios, and with Thek and Obernberger (2004),
who stated that the production costs for wood pellets are main-
ly influenced by the raw material costs and, in the case of
using wet raw materials, by the drying costs. These two pa-
rameters can contribute up to one third of the total pellet pro-
duction costs. In our findings, the lower production costs of
case 2 are essentially attributable to the processing of pellet
production that in this case is carried out for 40% of virgin
wood and 60% by sawdust (wood processing waste). As sug-
gested by Kang et al. (2013), mixing lumbering by-products
(sawdust) and forest management products (lumber) in appro-
priate ratio rather than to use only sawdust or lumber can be an
efficient solution for reducing the manufacturing costs of
wood pellet production.
6 Conclusions and future perspectives
Under our experimental conditions, the production of 1 t of
pellets mainly from sawdust (case 2) had a lower impact and
lower production costs, if compared with the pellet production
using beech logs in case 1. Furthermore, in both analysed
cases, the operations carried out in the forest produced the
minor part of the impact but, at the same time, were the most
expensive operations.
We can conclude that the combined use of LCA and LCC
could be useful to provide information for policy makers and
producers in choosing sustainable management systems or
products. Furthermore, Basilicata region, with its high rate
of forested areas, if better managed, can help Italy to satisfy
its domestic needs without resorting to imports and create a
sustainable, low-carbon, resource-efficient and competitive
economy.
Indeed, future perspectives concern, on the one hand, the
precision,completeness and representativeness of the data and
the consistency and reproducibility of the methods used; on
the other hand, future studies should concern the expansion of
the economic analysis of the production of wood pellets, also
including the monetisation of the main effects, positive and
negative, on the environment.
Acknowledgements This research was carried out in the framework of
the project BSmart Basilicata^, which was approved by the Italian
Ministry of Education, University and Research (Notice MIUR n. 84/
Ric 2012, PON 2007-2013 of 2 March 2012) and was co-funded with
the Cohesion Fund 2007-2013 of the Basilicata Regional authority). This
work was also co-financed by Regione Basilicata Government-PO FSE
Basilicata 2007–2013—from sustainable forest management to market
for wood product (Project n. AP/05/2013/REG 2013).
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