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Concentrated Solar Power (CSP)
Concentrated Solar Power (CSP) plants
generate electricity by collecting incoming
solar radiation and concentrating it onto a
small area to generate high temperatures.
The heat is then used to drive conventional
steam generators. A CSP plant can be divid-
ed into two basic sections 1) the Collector,
which collects the incoming solar radiation
and converts it to heat and 2) the Generator,
which converts the collected heat into elec-
tricity. There are three main collector technol-
ogies available as outlined below:
1. Solar Trough: A solar trough consists of a
linear parabolic collector, which tracks the
sun on a single axis to focus the light onto an
absorber tube running along the focal length
of the troughs. The collector holds a carrier
fluid, which transfers the heat to the storage
medium or generator.
2. Power Tower: The power tower uses an
array of mirrors, which track the sun on multi-
ple axes to focus sunlight onto a central re-
ceiver, placed on the apex of a tower. Like
the solar trough, the collector holds a carrier
fluid, which transfers the heat to a storage
medium or directly to the generator.
3. Parabolic dish: This system consists of
stand-alone parabolic dishes which focus
sunlight onto a focal point. This can either
hold a collector, which holds a carrier fluid, or
a Stirling engine, which would generate elec-
tricity directly. Parabolic dish systems are
known for their very high efficiencies in con-
verting solar power to electricity.
The key variable for CSP projects is direct
normal irradiance (DNI), i.e. the amount of
radiation received by a surface always kept
perpendicular to the sun’s direct rays. The
electrical energy generation of a CSP plant
and thus electricity costs are directly depend-
ant on the available DNI. The map below
shows the annual DNI across Africa.
Total global installed CSP electrical gen-
erating capacity is 4.4 GW, so it is still a
young technology, but installations have
grown rapidly since 2010.
Wind Power
Wind energy is generated when the ki-
netic energy of the wind is harnessed by
large wind turbines and converted into
mechanical energy. To generate electric-
ity, this mechanical energy is used to
rotate generators situated in the hub of
each turbine. Wind turbines can range in
size from small home or boat based 50
W units to the large 6 MW commercial units
which have an overall height of nearly 200m.
Wind turbines for commercial power genera-
tion are generally arranged in an array, col-
lectively called a wind farm. Wind farms are
typically located in areas where a consistent-
ly high level of wind is present. The perfor-
mance of wind turbines increases exponen-
tially with the linear increase in wind speed.
Therefore consistent strong winds are critical
to the financial viability of a wind farm. Wind
speeds are stronger at higher elevation lev-
els, and on top of smooth hills, which is why
most wind turbines are mounted on high
masts and on top of hills where possible.
Electricity generated from all the turbines in
This briefing note has been designed for use by city offi-
cials and planners working in sub-Saharan Africa. It is a
practical guide, which identifies easy to achieve energy interventions that will
save money (for cities, businesses and households), promote local economic
development, and enhance the sustainable profile of a city. This note is spe-
cifically aimed as a support tool to achieve the implementation of key interven-
tions within municipalities across sub-Saharan Africa.
African municipalities need to be prepared to deal with an explosion in de-
mand for services from burgeoning populations caused by two factors – high
population growth in Africa as a whole, and rapid urbanisation. An interesting
feature of population growth in sub-Saharan Africa is that it is expected to
take place mostly in small and medium sized cities, rather than capitals (UN-
Habitat, 2010). These changes are taking place at a time when many coun-
tries are devolving administrative powers to local governments, yet municipal
authorities lack the skills and expertise to address challenges, to manage
resources, and to implement and enforce policies.
Energy is only one of many services that municipalities need to address in the
face of increasing urbanisation, but it is crucial to any form of urban develop-
ment – planned or otherwise. People need energy as part of their every-day
lives. The supply of energy is closely linked to economic development, health
and individual wellbeing, as well as to local and global environmental sustain-
ability.
Recognising the emerging role of municipalities, with limited capacity, in ad-
dressing energy provision in urban centres, the “Supporting African Municipal-
ities in Sustainable Energy Transitions” (SAMSET) project seeks to build
capacity and develop a practical and effective knowledge exchange frame-
work for supporting actors involved with municipal energy planning. This note
is an output of the SAMSET project.
The purpose of the note is to give planners an idea of the range of energy
interventions that it is possible for them to implement at the municipality level.
It provides enough information to give a basic understanding of different ener-
gy technologies – enough to start making enquiries and engage in discussion.
More detailed technical expertise will, however, be needed in order to design
a bankable project.
Full guide can be found at africancityenergy.org/uploads/resource_101.pdf
More info can be found at africancityenergy.org/
More project info can be found at samsetproject.net
Created CC licence 2017
SAMSET brief on Other Renewable Energy Technologies
Overview
Image © NASA
the wind farm is combined and modified to feed
into the power transmission network in the area.
Global installed wind generating capacity is 430
GW. The market is dominated by China. South
Africa and Ethiopia are the only sub-Saharan
countries with substantial wind capacity (1,050
MW and 320 MW respectively at end 2015).
Solar Water Heaters
A solar water heater uses energy from the sun to
heat water and works on two basic principles.
Firstly, when water gets hot it rises due to densi-
ty differences between hot and cold water
(thermosiphon effect) and secondly, that black
objects absorb heat.
A solar water heater comprises three main parts:
the collector, the storage tank and an energy
transfer fluid. Solar water heaters are classified
as either active or passive and direct or indirect
systems. They may make use of either flat plate
collectors or evacuated tubes.
The global installed capacity
at end 2014 was 410 GWth.
Over 70% of this was installed
in China, and only 0.3% in
sub-Saharan Africa, and this
was predominantly in South
Africa. The dominant technol-
ogy was evacuated tube col-
lectors (71%). Roughly half of
the capacity in sub-Saharan
Africa was used for small
scale domestic hot water
systems (single household), and half for heating
swimming pools (reflecting use in South Africa).
Concentrated Solar Power (CSP)
One of the main benefits of CSP, especially
when compared with other renewable energy
technologies such as wind and PV, is the relative
ease of energy storage. As the concentrated
solar energy is used to generate heat, this heat
can be stored (often as molten salts) in insulated
containers and then used to generate electricity
on demand, even when there is no sunshine.
This means that CSP can be used to meet tran-
sient peak loads in grid connected applications,
and it can provide 24 a day power in off-grid
applications.
CSP deployment in sub-Saharan Africa has only
started in recent years, mainly driven by the
Renewable Energy Independent Power Produc-
er Program (REIPPP) in South Africa.
Wind Power
SSA’s installed wind energy capacity increased
14-fold between 2003 and 2010. Due to wind
speeds, the greatest potential for wind power
exists in West Africa.
Countries such as South Africa, Morocco, Egypt,
Cape Verde, Ethiopia, Kenya and Tanzania are
currently developing wind farms. Somalia, Su-
dan, Madagascar, Kenya and Chad – have large
on-shore wind energy potential. Five additional
SSA countries – Mozambique, Tanzania, Ango-
la, South Africa and Namibia – have potentially
large off-shore wind energy resources.
The best wind potential in SSA is found in
coastal regions whether in the East (Djibouti,
Eritrea, Seychelles and Somalia), West (Cape
Verde) or South (South Africa and Lesotho).
With the exception of Chad and Ethiopia, whose
topographies give rise to high speed winds in
certain high altitude areas, the rest of land-
locked Africa’s wind intensity is too low to be
harnessed for electric power generation.
Solar Water Heaters
It’s difficult to argue a case for solar thermal
water heating because little data is available
from sub-Saharan countries on the energy ex-
pended on heating water. It is common practice
to put a pot of water on a stove after cooking is
finished in order extract heat from the embers.
This makes it difficult to apportion energy con-
sumption between cooking and water heating. A
case for solar water heaters can only be made
where people are paying for the energy used;
this is why the market is biggest in South Africa,
where households typically use electricity to heat
water.
For households, a solar water heater (SWH) has
several benefits:
Water heating accounts for 40-60% of total elec-
tricity consumption for a typical home in South
Africa. Electric water heating costs can typically
be reduced by 70% with a SWH. This amounts
to about a 25 to 30% saving on an average
monthly electricity bill. This presents a strong
financial case for replacing electric geysers with
solar water heaters.
Climate change mitigation. From an environmen-
tal perspective, water heated mostly by the sun
will reduce a household’s CO2 emissions by
displacing the use of fossil fuels or unsustainably
sourced biomass otherwise used to generate
electricity; the amount will depend on the electric
utility’s generation mix (e.g. electricity in South
Africa is generated mostly from coal, so CO2
savings will be high).
Energy security: In regions where there are lim-
Case Studies: Eskom’s Solar
Water Heater Rebate Programme
Eskom in South Africa has long been
promoting a range of energy efficiency
measures as they
struggle to meet increasing demand for
electricity. In 2008 they introduced the
Solar Water Heater Rebate Programme.
The South African government required
Eskom to substitute 10,000 GWh of elec-
tricity with renewable energy. The rebate
programme set a target of replacing elec-
tric geysers in 1,000,000 homes with
SWHs, and was expected to achieve 23%
of Eskom’s overall target. Funds were
made available for a five year period by
the National Energy Regulator of South
Africa (NESRA).
In 2015, Eskom withdrew from the
scheme, which was then suspended; by
this time 425,000 solar systems had been
installed. One of the reasons given for the
underperformance of the programme was
poor installation quality. As details of the
scheme changed, subsidies were shifted
in favour of locally manufactured systems,
as a means of stimulating the South Afri-
can SWH industry. Only systems with at
least 70% local content became eligible
for the scheme. This then ruled out the
use of evacuated tube type systems, as
these are not made in South Africa.
Despite these setbacks, the government
remains convinced of the value of SWHs.
The National Development Plan set a long
term target of 5 million systems by 2030,
and the government committed to a re-
viewed national SWH programme in 2015.
The Case
Image © Cadbury
Image © Blue Carbon
ited natural resources, fuels for generating
electricity are often imported at high cost.
These technologies can improve energy secu-
rity and reduce pressures on international
energy markets.
Where SWHs displace dirty fuels, such as
biomass, households will enjoy health benefits
and improved quality of life.
Concentrated Solar Power (CSP)
Most sub-Saharan countries receive solar
radiation in the range of 6-8 kWh/m2/day,
which counts among the highest amounts of
solar radiation in the world. Until now, only a
small fraction of Africa’s vast renewable ener-
gy potential has been tapped.
There is substantial growth potential in the
deployment of small-scale CSP for industrial
process heat, offering significant benefits. In
Africa this is by as much as a factor of 4,600
by 2050. According to the International Re-
newable Energy Agency (IRENA), total in-
stalled renewable capacity in sub-Saharan
Africa is expected to grow from 28 GW in 2010
to around 800 GW by 2050, with wind ac-
counting for 242 GW, and concentrated solar
power for 94 GW.
CSP is attractive because its efficiency in-
creases with irradiation level, which is not the
case for solar PV where efficiency declines
with rising collector temperatures. Given that
the irradiation level corresponds also with the
demand for air conditioning, solar CSP would
reduce the need for peak capacity. This fea-
ture is attractive in desert countries where
solar irradiation is particularly strong.
CSP systems offer the opportunity to store
solar energy as heat, which can be used to
generate electricity during periods of low or no
sunshine. This attribute is a considerable ad-
vantage over solar PV when CSP is used for
electricity generation, because a large-scale
on-grid CSP plant can use the stored thermal
energy to run its turbines and feed electricity
into the grid for several hours after sunset (in
many countries this may be a period of high
demand). CSP systems with thermal storage
have higher investment costs, but they allow
higher capacity factor and dispatchability.
Wind
The theoretical potential for wind in Africa
exceeds demand by orders of magnitude, and
about 15% of the potential is characterised as
a high-quality resource. This enormous capac-
ity is not evenly distributed: East, North and
Southern Africa have particularly excellent
wind resources (ibid). The map below shows
wind speeds across Africa.
Wind potential in Ghana is seen as marginal –
average annual wind speeds are 4-6m/s at
50m above sea level along the coast and on
some islands. However, some areas near the
border with Togo have wind speeds above 8m/
s. Currently, there are no wind energy installa-
tions in Ghana except for small off-grid ones
installed for demonstration purposes. Three
groups are currently undertaking wind re-
source data assess-
ments; these are:
the Energy Commis-
sion, Volta River
Authority, and UP
Wind Company.
According to the
Alternative Energy
Resource Assess-
ment and Utilization
Study carried out
between June and
September 2003,
the wind energy
resource in Uganda is insufficient for large
scale electricity generation.
The continent’s largest wind farm is currently
being constructed in Kenya, by Lake Turkana,
and will have in installed capacity of over 300
MW. The project is registered under the Clean
Development Mechanism (CDM), which
means it can generate revenue from selling
carbon credits, and demonstrates the viability
of large scale schemes in Africa.
However, as costs in Africa are expected to
drop further with increased availability of local-
ly manufactured components such as towers
and blades, it is likely that wind farms will be-
come more prevalent across sub-Saharan
Africa in the future.
Solar Water Heaters
Domestic solar water heaters have been suc-
cessfully introduced in Asia and in southern
and northern Africa, with eastern African ef-
forts recently starting in Kenya. Since 2009,
the South African Government has supported
this technology through schemes where a
rebate is paid directly to consumers, provided
the product, supplier and installers are regis-
tered in the programme. The rebate signifi-
cantly reduces the cost of solar systems,
making water heating more affordable
for a large proportion of customers. Over
400,000 systems were installed under
the programme, and it is currently being
revised (see Case Studies).
A survey in Ghana found that the aver-
age daily hot water requirement for a
household of 3 was estimated to be 80
litres per day. A cost-benefit analysis
revealed that the payback period for a
solar water heating system would be 8
years given a lifespan of 20-30 years.
Future buildings should therefore include
solar water heaters in their architectural
designs. This will make installation of
such systems much easier and cost
effective.
Case Study: Lake Turkana Wind
Farm, Kenya
Wind farms are a lucrative investment arena
for the African Development Bank (AfDB), as
shown by their commitment to the 300 MW
Lake Turkana Wind Farm in Kenya. The
Lake Turkana Wind Power (LWTP) consorti-
um is constructing a wind farm consisting of
353 wind turbines, each with a capacity of
850 kW, in Northwest Kenya. LTWP can pro-
vide reliable and continuous clean power to
satisfy up to about 30% of Kenya’s current
total installed power.
Potential for Rollout
Image © KBC TV
Concentrated Solar Power (CSP)
The key barriers for small scale industrial
applications are low awareness that CSP is
a potential energy source for industrial pro-
cess heat, lack of confidence that the tech-
nology works in local conditions and applica-
tions, and payback periods that are consid-
ered unattractive by potential customers. For
rural/off-grid applications the critical barrier is
the lack of an optimised and proven technol-
ogy solution.
When compared to PV, CSP projects are
more difficult to develop, finance and to im-
plement. Given that significant economies of
scale exist for CSP, projects should come
from a techno-economic point of view. The
large up-front investments, offering greater
prospects for cost reductions, also make it
more difficult for emerging CSP technologies
to be commercialised.
Wind
The underdevelopment of wind markets
reflects affordability issues as well as socio-
political and technical considerations. It has
been widely argued that renewable energy is
not a priority for SSA given more basic is-
sues that these countries are dealing with,
such as high poverty rates, stagnant eco-
nomic growth, and health crises, and that
until renewable sources are cost-effective,
African countries should not pay a high price
due to past pollution from advanced econo-
mies.
Wind energy also poses negative effects on
the environment through its effects on wild-
life, visual impact and noise pollution. There
is also substantial competition between wind
and other well established renewable energy
sources such as hydro, which have the capi-
tal cost advantage and favourable physical
attributes such as the ability to store energy.
Solar Water Heaters
Issues affecting the uptake of domestic solar
water heaters include the high up-front in-
stallation costs compared with gas and elec-
tric boilers, the complex process and associ-
ated costs to integrate solar thermal systems
into existing housing, competition with heat
pumps, and in some cases the competition
with PV panels for rooftop space. Moreover
in parts of Africa electricity and fossil fuel
subsidies have acted as inhibitors to large-
scale deployment.
Clean Development Mechanism
Under the Kyoto Protocol, the Clean Devel-
opment Mechanism (CDM) provides for
emissions reduction projects which generate
Certified Emissions Reductions units
(CERs). These can be then be traded on the
carbon market. The recent introduction of the
programme of activities (PoA) under the
CDM is expected to greatly enhance the
opportunities for African countries to access
the CDM. Examples of activities carried out
in sub-Saharan Africa include the roll out of
solar water heaters for domestic use.
Ghana’s Renewable Energy Act
The Renewable Energy Act of 2011 provides
for the development, management, utiliza-
tion, sustainability and adequate supply of
renewable energy for generation of heat and
power for related matters. Key Provisions in
the act include the feed-in-tariff scheme and
the purchase obligation.
Feed in Tariffs
Both Ghana and Uganda have implemented
Feed in Tariffs for the promotion of renewa-
ble energy use. CSP is not regarded as a
sufficiently mature technology to be included
in these arrangements. It is somewhat sur-
prising that Uganda has no provision for
electricity generated by solar PV but this is
because, at the time the tariffs were last
revised, PV was still regarded as too expen-
sive. However, PV prices have since fallen
dramatically.
Solar Bylaw
A city bylaw can enforce the installation of
solar water heaters in:
all new buildings built in a city;
all additions to existing buildings in the city
where extra water heating for sanitation pur-
poses will be required.
Given that the financial case is clearly bene-
ficial to the end user for all households that
require a hot water system, this is a poten-
tially very effective mechanism to drive im-
plementation and stimulate the solar water
heater industry. In order to allow for initial
supply capacity deficits, a tiered introduction
process can be adopted to ensure the indus-
try keeps up with the new growth in demand.
This document is an output from a project co-
funded by UK aid from the UK Department for
Internaonal Development (DFID), the Engineer-
ing & Physical Science Research Council (EPSRC)
and the Department for Energy & Climate
Change (DECC), for the benet of developing
countries. The views expressed are not neces-
sarily those of DFID, EPSRC or DECC, or any
instuon partner of the project.
Case Study: Namugoga Solar Power
Station, Uganda
Namugoga Solar Power Station is a proposed 50
megawatt CSP plant in Uganda. The power gen-
erated will be sold directly to the Uganda Elec-
tricity Transmission Company Limited, the sole
authorized purchaser. The electricity will be ex-
ported from the station to a substation in Kisubi
for integration into the national electricity grid.
Image © Solar Africa
Implementation
Barriers to Implementation
