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Water-Energy-Food nexus interactions assessment: Renewable energy sources to support water access and quality in West Africa


Abstract and Figures

Mitigating the big challenges of access to clean water, energy and poverty in Africa requires integrated solutions. The analysis of issues related to the water, energy, food and the ecosystem through a nexus approach, has attracted the interest of scientists, policy-makers and the private sector. The present Technical Report examines the potential of such an approach to create beneficial synergies between the energy, water and agriculture sectors in Africa. Thus, it presents the potential of the solar Photovoltaic technology to support efforts for sustainable development. Solar-based water pumping systems and their technical characteristics are presented in detail. Their advantageous characteristics under certain conditions are compared to the current common practice of fossil fuel-based water pumps, that is clearly not sustainable. Equally important the report discusses the potential of solar pumping systems to provide electricity to communities, through the development of rural mini-grids. The suitability of such an approach is then analysed based on technical characteristics, the availability of solar irradiation, the economics-incentives as well as the climate policies. The aim is to add to the existing knowledge related to a technology that can utilize local African renewable energy sources and extract water resources that will eventually support agricultural activities, food production and economic development.
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Water-Energy-Food nexus
interactions assessment
Renewable energy sources
to support water access
and quality in West Africa
Kougias I., Szabó S., Scarlat N., Monforti F.,
Banja M., Bódis K., Moner-Girona M.
EUR 29196 EN
Report EUR xxxxx EN
2 0
x x
Forename(s) Surname(s)
First subtitle line first line
Second subtitle line second
First Main Title Line First Line
Second Main Title Line Second Line
Third Main Title Line Third Line
This publication is a Technical report by the Joint Research Centre (JRC), the European Commission’s
science and knowledge service. It aims to provide evidence-based scientific support to the European
policymaking process. The scientific output expressed does not imply a policy position of the
European Commission. Neither the European Commission nor any person acting on behalf of the
Commission is responsible for the use that might be made of this publication.
Contact Information
Name: Ioannis Kougias
Address: European Commission, Joint Research Centre, Via Enrico Fermi 2749, 21027
Ispra (VA), Italy
Tel.: +39 0332 785681
JRC Science Hub
EUR 29196 EN
PDF ISBN 978-92-79-84034-0 ISSN 1831-9424 doi:10.2760/1796
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How to cite this report: Kougias I., Szabó S., Scarlat N., Monforti F., Banja M., Bódis K.,
Moner-Girona M., Water-Energy-Food Nexus Interactions Assessment: Renewable energy
sources to support water access and quality in West Africa, Luxembourg, European
Commission, 2018, EUR 29196 EN, ISBN 978-92-79-84034-0, doi:10.2760/1796.
All images © European Union 2018, except: Cover image, source: ©roibu–Shutterstock
Abstract ................................................................................................... 1
1 Introduction .......................................................................................... 2
2 Water-Energy interactions in SSA: Status and perspectives ............................... 5
2.1 Water requirements in rural communities: Background................................ 5
2.2 Conventional approach: fossil fuel-based water extraction............................ 6
2.3 Solar PV systems for water provision ...................................................... 7
2.4 Configurations of solar-based water pumping systems................................. 9
2.4.1 Grid-connected system ................................................................... 9
2.4.2 Stand-alone photovoltaic system....................................................... 10
2.5 Developing a mini-grid from a PVWPS ..................................................... 13
2.6 PVPWS in front of the water and energy African challenges ........................... 14
3 The Energy dimension in the WEF interactions in Africa .................................... 16
3.1 Renewable energy in West African Countries: State of art and projections ........ 16
4 The Water dimension in the WEF interactions in Africa ..................................... 20
4.1 Importance of irrigated agriculture in SSA ................................................ 21
4.2 Small-scale farming in SSA................................................................... 22
4.3 Drip and micro irrigation ...................................................................... 23
4.4 Water storage and its opportunities ........................................................ 24
4.5 Type of pumps .................................................................................. 25
5 Suitability of solar-powered water extraction in Africa ...................................... 28
5.1 African solar resource potential ............................................................. 28
5.2 Economics of solar photovoltaic technology .............................................. 29
5.3 Economics of battery storage ................................................................ 30
5.4 Initiatives for PVWPS deployment in developing countries ............................ 30
5.5 Solar-powered water extraction in W. African climate policies ........................ 31
5.5.1 The ECOWAS Renewable Energy Policy ............................................... 31
5.5.2 West African Nationally Determined Contributions (NDCs) ....................... 31
6 Conclusions........................................................................................... 32
References................................................................................................ 34
List of abbreviations and definitions................................................................. 40
List of figures ............................................................................................ 41
List of tables ............................................................................................. 41
Mitigating the big challenges of access to clean water, energy and poverty in Africa
requires integrated solutions. The analysis of issues related to the water, energy,
food and the ecosystem through a nexus approach, has attracted the interest of
scientists, policy-makers and the private sector. The present Technical Report ex-
amines the potential of such an approach to create beneficial synergies between the
energy, water and agriculture sectors in Africa. Thus, it presents the potential of the
solar Photovoltaic technology to support efforts for sustainable development. Solar-
based water pumping systems and their technical characteristics are presented in
detail. Their advantageous characteristics under certain conditions are compared
to the current common practice of fossil fuel-based water pumps, that is clearly not
sustainable. Equally important the report discusses the potential of solar pumping
systems to provide electricity to communities, through the development of rural
mini-grids. The suitability of such an approach is then analysed based on techni-
cal characteristics, the availability of solar irradiation, the economics-incentives as
well as the climate policies. The aim is to add to the existing knowledge related
to a technology that can utilize local African renewable energy sources and extract
water resources that will eventually support agricultural activities, food production
and economic development.
1 Introduction
The present Technical Report examines the potential synergistic benefits to energy,
water and agricultural production practices in Africa, arising from an appropriate use
of clean energy sources. Indeed, the deployment of energy production systems
based on the utilization of indigenous African renewable sources can provide the
required energy to extract, process and convey water resources that will eventually
support agricultural activities and food production.
It is worth noticing that interactions between water, energy and food in a nexus
approach are crucial for the implementation of the United Nations (UN) Sustainable
Development Goals (SDGs). SDGs —also known as the Global Goals— are a UN
initiative to fight poverty, protect the planet and promote peace and prosperity.
Out of the total seventeen SDGs (Griggs et al., 2013, UN, 2015), three of them
have a particular focus on water, energy and food1. Accordingly, SDG#2 aims at
fighting hunger and malnutrition. SDG#6 aims at providing access to safe water
and sanitation as well as ensuring a sound management of freshwater ecosystems.
SDG#7 promotes energy access for all and supports actions to meet targets for
increased share of renewable energy sources’ (RES) use and high levels of energy
efficiency (EE).
The document at hand focuses on Sub-Saharan Africa (SSA) with a special
attention on West Africa. indeed SSA faces very serious challenges as far as the
SDGs are concerned to the level that it could be even said that SSA is the epicentre
of this challenge as nearly 70% of the population does not have access to elec-
tricity (IEA, 2014), the equivalent of 621 million people lacking access to modern
energy. Recent analyses have also shown that if the conventional electrification
strategies are maintained, this will result in a further rise of the energy poverty
(Szabó et al., 2016). As far as access to water is concerned, by 2013 most SSA
countries had failed to meet both the rural and urban targets (Dos Santos et al.,
2017) presented in the United Nations Millennium Declaration (Millennium Devel-
opment Goals) and one fifth of the population still faces serious water shortages
(Rockström and Falkenmark, 2015).
Between 2014 and 2015, 153 million individuals living in SSA suffered from
severe food insecurity (FAO, 2017a). Although undernourishment was halved dur-
ing the period 1990–2015, the 2017 food security situation in Africa is still alarming,
with 108 million people affected by food crises already in early 2017 (JRC, 2017b).
It is important to note that several countries in SSA remain highly dependent on
food imports to ensure adequate food supplies, a reality that highlights the need
to increase agricultural productivity and food production. These challenges will fur-
ther exacerbate as the region’s population is expected to double by 2050, from the
current 1.2 billion to more than 2 billion in 2050 (JRC, 2017b).
In combination with the population trends, climate change is expected to im-
pact the seasonal variation of precipitation, temperature and solar irradiance for
SSA and West Africa changing the distribution of surface waters available for irriga-
tion will change. Indeed, Africa is one of the most vulnerable continents to weather
and climate variability, according to the latest estimations of the Intergovernmen-
tal Panel on Climate Change (IPCC, 2013). In most of the analysed scenarios the
temperature shows significant increase in all SSA regions, while the yearly distri-
bution of the precipitation does not follow the same increasing pattern (Bartholomé
1Detailed information on the SDGs is available online at the UN Sustainable Development
Knowledge Platform.
E et al., 2013), with the majority of climate models projecting decreases in annual
precipitation that reach 20% by 2080 (Conway et al., 2015). At the same time it
is expected that the agricultural production will require larger water quantities for
irrigation, to maintain and increase the output. Thus, scaling up the efficient and
sustainable utilization of both surface and groundwater resources is absolutely nec-
essary to adapt to a dynamically changing environment and the increasing needs
for food production.
While globally the percentage of irrigated areas amounts to about 20% of the
arable land area, in Africa only 7% of the arable area is irrigated. This percentage
falls further at 4%-levels in Sub-Saharan Africa, clearly showing that the irrigation
potential in SSA is largely untapped. At the same time, irrigation is clearly necessary
if agriculture needs to boost: yields of rainfed areas in Sub-Saharan have risen
very little or even remained stagnant, due to the slow development of irrigation
methods. Although the role of rainfed agriculture needs to be strengthened to
support increased crop production (Wani et al., 2009), such an approach faces
limitations and is vulnerable to a wide extend to climate variability.
In 2005, the Commission for Africa2published a report titled Our common fu-
ture (CfA, 2005) that recommended Africa to double its irrigated farmland by 2015,
as part of the measures to promote agricultural and rural development. The cost of
such a transition was estimated at US $2 billion per year. Presently, three years af-
ter the initial deadline, only little progress on the planned actions has been achieved.
Aiming to more flexible and faster-to-implement solutions, the general consensus
clearly leans towards small-scale irrigation. Scientists, developers, policy officers
and international organizations welcome investments that manage water resources
following the community-based irrigation paradigm. Small-scale water harnessing
and irrigation is particularly suitable for rural communities, as such —relatively low-
cost— technological solutions are implemented in a scale that enables beneficiaries
to engage and be actively involved in both the design and implementations phase
(FAO, 2008).
Thus, the complementary role of rainfed agriculture should be coupled by
concrete actions to support irrigated agriculture. This includes the adoption of new
technologies and modernizing infrastructure including the utilization of solar pho-
tovoltaic water pumping systems (PVWPS), which is the objective of the present
In the report the technical characteristics of PVWPS and variations of their
configuration are presented together with an extensive bibliographic research aim-
ing at presenting their advantages compared to conventional methods and placing
them in the context of recent needs, tendencies and policy requirements. At the
same time, published case studies and lessons learned acquired from real-world ap-
plications in different geographical regions are discussed. In this way the reader is
made aware of the bottlenecks and limitations of the solar-based irrigation technol-
ogy, its possible application fields along with the required technical breakthroughs
that may expand their utilization.
A special feature of the PVWPS is its potential dual use for electricity produc-
tion, in periods the needs for water decrease or completely seize. Accordingly, it
is expected that the PVWPS could be utilized in the remaining periods for other
2The Commission for Africa was set up by Tony Blair, who was then serving as the Prime Minister
of United Kingdom. The Commission for Africa had seventeen members, nine of which were African
states. By 2017 all the previous governance programmes led by Tony Blair had seized operation and
transitioned into the Tony Blair Institute for Global Change.
purposes such as water purification, conveyance and electricity production. This
flexibility of usage along with the advantage of the negligible operation cost of
PVWPS, opens a new perspective for the sustainable development of rural areas.
Moreover, PVWPS modularity also allows for different settings and a great variabil-
ity of systems’ configurations, adapted to the very specific needs of each location.
The various options and configurations are also presented in detail in the report,
along with their advantages and limitations.
Finally, the extended bibliographic research performed in terms of the present
research revealed that the research on water and energy access in SSA is rather
fragmented and would profit of enhancing the nexus approach. Indeed, a rel-
atively extensive bibliography on PVWPS utilization for rural communities exists,
while at the same time the discussion on the rural electrification of SSA based on
clean and renewable resources has already fructified influential spatial analyses in
continental- (Szabó et al., 2011,Szabó et al., 2016) or country-level (Moner-Girona
et al., 2016a,Moner-Girona et al., 2016b,Moner-Girona et al., 2017) and resulted
in important actions from international organizations to promote renewable-based
energy solutions. However, the synergies between water and energy development
in SSA have not been studied under the same framework to date, at least not suf-
ficiently. The present report aims to contribute to the efforts to cover this gap and
—equally important— provide input to those involved in the sustainable develop-
ment of Africa. Jointly addressing the challenges of limited access to clean water
and energy has several advantages and efficiencies. The latter are at the core of
the ongoing water–energy–food (WEF) nexus discussion, that suggests addressing
challenges in these three fields in an integrated.
The Technical Report has the following structure: Section 2 outlines the cur-
rent status of the WEF nexus in Sub-Saharan Africa. The water needs of the rural
communities for household, agricultural and livestock use are presented along with
the prevailing strategies to secure the required water. The criticality of the current
status from the sustainability point of view are underlined and the alternative solar
PV-based technology for water pumping is presented in detail (components, various
configurations, mini-grid formation etc.). Section 3.1 focuses on the energy dimen-
sion of the WEF nexus approach. Current status of the renewable energy capacities’
deployment is presented, along with the commitments and plans for future actions
of the West African States. Section 4 aims to cover the water dimension of the
WEF nexus analysis. It collects information on the type of farming, irrigation prac-
tices and the particularities of agricultural productivity, in the SSA context. It also
presents the water components that could potentially help SSA leapfrog outdated
irrigation technologies and directly adopt the best practices. The suitability of such
an approach is presented in section 5, both in terms of available resources’ assess-
ment as well as in terms of technical and economical feasibility. Recent and current
initiatives and policies are also presented in order to identify the starting point for
future action. A brief conclusions section outlines the findings, presents the poten-
tial and existing challenges, and provides policy recommendations to promote the
sustainable use of energy and water in Africa.
2 Water-Energy interactions in SSA: Status and perspectives
2.1 Water requirements in rural communities: Background
Depending on their location rural communities of SSA rely on different water sources.
The availability of these sources typically varies throughout the year, following the
seasonality of the local climate conditions. During the rain period and shortly after,
surface water sources usually cover the various needs. In some cases the water
concentrated in shallow formations below the surface is collected from shallow wells
and boreholes with the use of hand pumps. In the dry season i.e. the period of
low precipitation, such sources dry up. Accordingly, an increasing need for water to
cover drinking, irrigation and livestock needs depends on the fewer remaining wa-
ter sources. It is this time of the year when mechanised equipment is particularly
important to secure water supply. Mechanised pumps have a much higher yield
than hand ones and —more importantly— the required capacity to extract water
from deep boreholes and larger distances. During these dry periods water sales
and the relevant market prices reach their peak, with the cheapest water generally
being the one of the poorest quality.
Water extraction is an energy-intensive process that often creates a heavy
economic burden to the African farmers. It requires significant amounts of energy
that depend on the local conditions and generally range between 1.36–2.16 MJ/m3
(the equivalent of 0.38–0.60 KWh/m3) (Harvey, 2010). Conventional power sources
for the operation of the pumping machinery is fossil fuel generators, mainly diesel
gensets. The use of electricity-powered water pumps have recently become increas-
ingly widespread in the emerging economies of Southeast Asia, but their utilization
in SSA is still limited. Achieving higher agricultural yields requires additional water
extraction and correspondingly extra energy. Thus, the growing energy demand
for expansion of the irrigated agriculture creates the need to examine alternative
energy sources (Ali, 2010).
Unfortunately, mechanized pumps involve significant monetary cost and com-
munities need to struggle to collect the required capital for both the installation
and the operation and maintenance (O&M) of pumping systems. A not rare and
unfortunate situation appears when a community that has access to clean source of
water cannot extract it due to economical or technical reasons: in such occasions
users perforce turn to accessible surface or shallow waters, that can be manually
collected. However, the water collected from scoop holes, like the one illustrated in
Figure 1, has questionable quality and exposes the users to significant health risks.
It is ironic that rural African communities may have significant water resources
laying in groundwater aquifers, beneath the surface. However, since water extrac-
tion from the low aquifer is not possible manually or with the use of hand pumps, the
use of such resources is necessarily abandoned. Besides, the exploration phase and
the required test drilling are an additional —often prohibitive— economic burden for
the communities. The recent example of Turcana, Kenya attracted global attention
(Kulish, 2013), as vast supplies of groundwater quantities were discovered under
the desert, boosting Kenya’s known water reserves by 17% (Gramling, 2013). This
very important discovery was made possible by the technological advances and the
use of the latest satellite radar image processing methods. Although the identifi-
cation and geo-location of existing resources exceeds the purpose of the present
report, the example of Kenya shows that novel and technologically advanced ap-
proaches can be profitably adopted all along the lifecycle of water provision projects.
Figure 1: Scoop hole in Turkana district, Kenya. Source: (Stevens, Lucy, 2014)
2.2 Conventional approach: fossil fuel-based water extraction
As a rule, mechanised boreholes in rural Africa are powered by diesel generators.
So far their importance has increased in parallel with any attempt to increase agri-
cultural productivity. The main advantage of these systems lies in their capability
to provide very high output, whenever needed. They have a relatively low capital
cost and can be operated on demand. However, diesel-powered systems have a
high operational cost due to the fuel consumption. Moreover, they require regu-
lar maintenance of the moving parts, adding to the overall cost. It is a common
phenomenon for a African communities that have access to a clean water source
and own a conventional diesel pump to be unable to extract it. This may be due
to several technology- or finance-related reasons. The following list highlights the
more common of them:
(i) There is no access to selling-points of the required fuel.
(ii) There is no capital to purchase the required fuel.
(iii) Users choose low-quality water source over a cleaner one, to avoid/decrease
fuel cost.
(iv) The pump is not working due to a technical failure.
It is important to underline the fourth point i.e. the high failure rate of diesel-
powered water systems. Their equipment is often poorly maintained to avoid the
related cost, therefore there is a high risk of failure, especially if they are heavily
used. Evidence in the literature related to the annual operation and maintenance
cost of conventional pumps, mention that it is approximately equal to the 15% of
the capital investment cost (Qoaider and Steinbrecht, 2010).
As the dry season arrives, needs for water increase further, while the ground-
water level may fall dramatically. Consequently, pumps need to extract water from
lower depths, a requirement that leads to decreased pumping rates. Accordingly,
in order to respond to the demand, pumps operation is extended and even reaches
18 hours of continuous operation per day. Such a heavy usage often leads to their
break down, completely disrupting access to water until the required maintenance
is completed. However, in the rural areas of SSA spare parts and skilled technicians
may not be readily available in the vicinity to repair the device immediately. Ac-
cordingly, a failure often results in long periods without access to water for irrigation
in the periods that is mostly needed, with catastrophic impact to crop production.
Even in those cases that skilled technicians are available and a spare parts sup-
ply chain is in place and secures access to spare parts, diesel gensets need to be
continuously monitored and maintained. Replacement of engine oil is required as
frequently as every 250 hours of operation, while a complete overhaul of the genset
is typically foreseen after 15,000 hours of operation.
During the dry period farmers and stock breeders have indeed a limited eco-
nomic means as the crops are to be harvested and the productivity of animals
decreases. The high O&M cost of the conventional, fossil fuel-based approach leads
to a paradox, that characterizes diesel-powered water extraction systems: their
O&M costs mainly appear in periods of low availability of capital. Thus, when water
extraction is mostly needed, users are least able to afford to operate diesel-powered
water systems. This is a major limitation of the conventional approach; attempts
to overcome it include national and international subsidies to provide fuel, spare
parts and technical support to overhaul aged equipment. However, such attempts
cannot be regarded as successful as they have a short-term horizon, are subject
to budget availability, distort the market mechanisms and —more important— cre-
ate dependencies to supporting schemes that simply perpetuate the challenge and
procrastinate a structural solution.
The need to explore alternative energy sources than conventional fossil fuels
and diesel has also been driven by the oil price fluctuations. The continuous price
rise between 1999 and 2008, when the spot price of oil reached record levels of
almost US $150 per barrel, mandated the transition to electricity-based irrigation.
Although this transition was realised in Southeast Asia (e.g. the case of India), it
was not implemented in SSA, due to the low access to electricity of the rural regions.
Remote rural areas in SSA have an additional particularity: the fuel needs to be
transported over large distances from the main cities and hubs. In such cases fuel
transportation involves a significant cost, because on one hand supply chains are
underdeveloped and on the other Africa transport infrastructure is underdeveloped,
Accordingly, fuel transport costs are almost twice as high as the world average (Wim
and Matthee, 2007).
2.3 Solar PV systems for water provision
The main alternative options to fossil fuels are the renewable energy sources, with
the solar technology being at a competitive level of maturity. It is also characterized
by technical compliance with water machinery, that has allowed its usage for water
extraction. Recent R&D activities have focused on developing PVWPS that can re-
place existing diesel-powered pumps by solar-powered engines. This compatibility
makes the transition to solar pumps affordable, because it allows maintaining the
irrigation system (including the pump) as it is and simply replacing the diesel en-
gine with a solar-powered one (Roblin, 2016). Utilizing existing infrastructure for
multiple purposes has been identified as an effective approach in the SSA context
(Szabó et al., 2016) and particularly suitable to water-energy nexus solutions.
A PVWPS water pumping system can have different settings, as explained in
the following text. A typical configuration consists of a solar PV array, a pump that
is either direct current (DC) or alternating current (AC) and the automation-control
system. Naturally, the PV array can have fixed position or adopt a 2-axis tracking
system. The used motor pump set depends on the technical specifications and can
be surface mounted, floating or submersible.
Figure 2 shows the typical SPWPS configuration for irrigation. The solar PV
system powers the pump through an automation and control system. Pumped wa-
ter is temporarily stored in a water storage tank and then it flows with gravity to the
irrigation system. Water pumping starts at the beginning of the day and lasts until
the sunshine. The PVWPS can be operated throughout the year, even during peri-
ods of relatively lower water demand. This allows extending the irrigation period,
implementing additional harvests and eventually higher agricultural productivity.
Figure 2: Typical configuration of SPWPS for irrigation with water storage. Source: (Maupoux, 2010)
Figure 3 shows the typical configuration of a PVWPS for drinking water and
livestock water provision. The main difference with the case of Figure 2 lies on the
final user of the water, that are households and farms.
Figure 3: Typical configuration of SPWPS for drinking and livestock water provision with water
storage. Source: (Maupoux, 2010)
In both cases water storage in tanks plays a dual role: Firstly, it stabilizes the
hydraulic characteristics of the infrastructure by securing continuity of provision,
stable pressure and water flow (l/sec). Moreover, water storage in tanks is used to
store the excess pumped water and secure provision for the night hours or during
days with lower solar insolation. Accordingly, water tanks act as an indirect form
of energy storage with a lower cost than the alternatives (e.g. battery storage).
Storing excess water in periods of low demand to be used during the irrigation
months requires large tanks or reservoirs, the cost of which is generally prohibitive.
However, in the case a reservoir already exists in the vicinity of the system, its
utilization for trans-seasonal water storage may be an advantageous option.
Evidence has shown that the continuity of water supply is a major improve-
ment for the communities; improved continuity and reliability increase the actual
quantities of water provided to the communities. These quantities are generally
significantly greater than that of the diesel-based systems with similar nominal
capacity (Mcsorley et al., 2011). The main advantage of the PVWPS over the con-
ventional systems is their negligible O&M cost. Apart from being fuel-independent,
they also do not have moving parts, a characteristic that results in lower mainte-
nance cost and higher reliability. Indeed, past experience has shown that PVWPS
are highly reliable and most of the recorded system failures are largely due to the
system components (e.g. pumps, inverters) and distribution infrastructure (e.g.
piping, cabling) rather than the solar technology (IRENA, 2012). This shows the
advanced reliability of the core system, that further supports continuity of supply,
as a result of the large reduction in O&M challenges, disruptions of operation that
have significant impact to the consumers and the fuel-free operation.
An additional advantage of the analysed systems is their quiet operation. Con-
trary to conventional gensets, PVWPS are characterised by soundless operation due
to the absence of moving mechanical parts. This is particularly important for pump
systems installed in urban environments and populated areas as it avoids health
risk and supports the life quality and general welfare of the local population. It is
also particularly suitable to the small-scale farmers in SSA. Agricultural production
is often operated by families with the farms being the “backyard” of the family’s
2.4 Configurations of solar-based water pumping systems
The various settings of PVWPS are described in the following text. The studied sys-
tems’ different variations aim to cover different scale, needs, geographical location
and technical and economic requirements. In every case the ultimate goal is to
design a PVWPS system that is capable to meet both water and energy demands
under the specific conditions and the best possible economic terms.
2.4.1 Grid-connected system
In a grid-connected system, the PVWPS uses produced power for the pumps oper-
ation and feeds the excess power directly to the utility grid. During the night or in
cases of increased demand the system may draw power from the grid (Ali, 2010).
This approach is a hybrid one as it combines power from the grid with the solar
PV output. Naturally, it is also possible to have a hybrid grid-connected system
either with a diesel genset or with both solar and diesel. The following bullet list
aggregates the possible combinations:
(i) Power grid – solar
(ii) Power grid – diesel
(iii) Power grid – solar – diesel
The presented options imply a connection to the power lines that ideally allows
a bi-directional connection, similar to a net-metering scheme. It is nevertheless im-
portant to mention that allowing excess generation to be fed into the grid assumes
a two-direction connection with the grid, that requires relevant policy and regula-
tory adjustments. Such possibilities have been considered and piloted in several
countries so as to increase the utilisation rate of grid-connected PVWPS, reduce the
risk of over-extraction of water and the corresponding depletion of the groundwater
aquifer, as well as to optimize the overall social welfare increase (IRENA, 2016).
Options (i)and (ii)can be combined in a system that utilizes both renewable-
based and conventional systems, benefiting at the same time from the connection
to the grid. In such a configuration the diesel genset will operate only in periods of
high demand, reducing the initial capital investment of the PVWPS. It will also cover
night demand when needed and act as backup system. In any case it is required to
take into account the fuel transport distance when designing such a combination,
since fuel transport costs can be notable in the case of remote agricultural areas.
However, the grid infrastructure in developing countries and SSA in particular
does not reach most of the rural areas. On top of the absence of a grid connection,
rural Africa is sparsely populated and along with the low per capita consumption
make grid extension an expensive option, that is not expected to be realized in the
near future (Szabó et al., 2011). But even in those cases where grid is in place
or in the vicinity —and thus— easily extended, it is not certain that it will have
the required capacity to handle additional loads. In many of the rural areas that
are connected to the main gird, power provision is often unreliable. Disruptions
of supply and voltage fluctuations are common (IRENA, 2016) and the seasonal
increase of electricity demand for agricultural activities will put an additional burden
on the aged electricity networks, a burden that non all systems are able to bear.
2.4.2 Stand-alone photovoltaic system
Stand-alone photovoltaic systems operate and produce power independently of
other energy sources and —per definition— a stand-alone system does not interact
with a utility grid (Hansen et al., 2000). Thus, stand-alone systems aim at providing
a solution to limited applicability of the grid extension option, to provide electric-
ity to remote, rural areas of SSA. Such systems may be installed in the following
(i) Direct-coupled
(ii) DC load with battery storage
(iii) DC load with battery storage and charge controller
(iv) Hybrid solar – diesel
Naturally, the load for PVWPS can be both DC or AC, depending on the type
of pump that is installed. To date several companies produce pumps specifically
tailored for renewable energy water pumping. Such pump motors can be powered
using DC power, avoiding the need to install an inverter (Granich and Elmore, 2010).
In case of the selection of an AC pump, a common inverter that transforms DC (e.g.
24V) to AC (e.g. 230V) needs to be added.
i. Direct-coupled
In direct-coupled systems PV arrays are directly coupled to a DC motor and pump.
Accordingly, direct pumping is possible throughout the day. It starts its pump-
ing operation when sufficient solar insolation reaches the modules, exceeding the
radiation threshold (Kou et al., 1998). This threshold is also known as activation
current, it corresponds to the minimum solar input required to set the system in op-
eration and depends on the system configuration. The activation (starting) current
is the value of the current exactly when the motor receives voltage and the system
is still not rotating. Subsequently, the starting current decreases with the voltage
increasing to eventually converge to a steady-state, which is the operating point of
the system (Mokeddem et al., 2011). Thus, the initiation of the motor rotation and
the first water appear in slightly different time. Proper sizing of the system design
and especially a careful definition of the power capacity of the photovoltaic array
capacity are crucial to ensure that sufficient energy is produced to start operation
as early in the day as possible (Khatib et al., 2010).
The PVWPS reaches maximum values of discharge when the solar insolation
and PV array output reach their daily maximum values. After reaching its maxi-
mum, the discharge progressively decreases to seize its operation near sunset. It
is interesting to note that the increase of the output is not linearly related to solar
irradiation. At intermediate irradiation levels an increase of the irradiation results
to higher increase in the output than that resulting from an equal change at high
radiation levels. Every evening, after the system seizes its operation, it needs to
be switched off to avoid over heating.
The advantage of direct-coupled systems is that they have a very simple con-
figuration and are reliable. These characteristics are particularly important for re-
mote rural areas, where access to expertise and trained technicians might be diffi-
cult. However, in such systems, variations of solar irradiation and sizing limitations
lead to relatively low utilization of the solar potential. A typical motor-pump effi-
ciency for such systems usually does not exceed 30% (Mokeddem et al., 2011),
making this configuration suitable for water extraction from low head resources. It
provides access to water in areas of absolute need, where access is a priority over
the provision of a technologically advanced solution. This is shown by the fact that
direct-coupled systems with no battery or control are the norm in Nigeria (Cloutier
and Rowley, 2011).
ii. DC load with battery storage
Some of the limitations of direct-coupled systems can be addressed with the addition
of battery storage. Batteries need to be characterized by slow discharge rates and
high depth of discharge, to secure their long lifetime. When the PV array output
exceeds the demand or the maximum power that the motor can utilize, the surplus
energy will be stored in the batteries. Such a strategy will continue until the sun
goes down, at which point energy stored in the battery tank will be used to continue
the operation of the pump. In this respect, battery banks store energy when the
power produced by the PV system exceeds the load demand and release it during
the night or in periods of peak demand, if the PV output is insufficient.
This configuration is often the most cost-effective choice for applications in
remote regions with no access to the utility grid, because it allows optimal sizing
of the system, without affecting the main advantages of reliability and simplicity.
It allows to avoid over-sizing the PV system in order to respond to rare peak de-
mand. It also reduces the need for water storage, which beyond certain limits, i.e.
irrigating areas larger than few hectares, becomes an economic burden rather than
an advantageous option for the system’s optimal sizing.
iii. DC load with battery storage and controller
This configuration is a variation of the previous one, having the extra feature of a
controller that dictates the control strategy that describes the interactions between
the system’s components. With the abundance of automation and control equip-
ment and the achieved technological maturity, the cost of control components has
become relatively low, allowing their wide use in most of the new systems. The
general arrangement of parts and components of this configuration is presented in
the form of a block diagram in Figure 4.
Figure 4: Block diagram for a stand-alone PVWPS, with an AC motor-pump system. Source: Authors’
interpretation elaboration on information provided in (Hansen et al., 2000)
A charge controller manages the interaction between the PV arrays, the batter-
ies and the load, which in the case of PVWPS is the motor rotating the pump. The
controller monitors the battery voltage and with predefined maximum/minimum
values it reacts accordingly. Thus, the controller takes no action under normal op-
erating conditions, when the battery voltage (V) fluctuates between minimum and
maximum values. However, the controller disconnects the PV arrays from the sys-
tem in the following occasions, when battery voltage reaches some critical values
and the load (L) does not match the current produced by the PV arrays (C):
V > VM ax and L < C (1)
V < VM in and L > C (2)
Equation 1 protects the battery against excessive charging, when its voltage
increases above the maximum threshold and at the same time load is lower than
the current produced by the PV arrays. This phenomenon is known as load rejection
(Kaldellis et al., 2009) or curtailment and is a system’s self-protection mechanism.
In an opposite manner, Equation 2 protects the battery against excessive discharge,
with the load being disconnected when the battery’s voltage falls below the mini-
mum threshold while the load is higher than the PV arrays’ output.
iv. Hybrid solar — diesel
The fourth configuration is a variation of the stand-alone PVWPS. It uses a conven-
tional diesel genset for the pumping operation either to cover the night demand,
increase productivity, respond to peak consumption and act as a backup system in
case of a failure or O&M. Hybrid systems may also be cost-effective for large-scale
irrigation, especially when another power source (i.e. diesel) is already in place and
a larger system is needed.
As the transition towards sustainable water extraction involves replacing big
numbers of conventional–polluting diesel generators with solar-based ones, it is
certain that a large number of the former will stay idle and be retained for future use.
Therefore this option may become very common and even those PVWPS originally
designed to be stand alone, will often operate with a diesel genset as a backup. This
configuration is presented in Figure 5, also including the option for battery storage.
Figure 5: Hybrid solar PV and diesel generation scheme with battery storage. Source: (Hitachi
Zosen Corporation, 2013)
A similar configuration has been tested for more than a year in a system
providing electricity and heating for a hotel in Praetoria, South Africa (Sichilalu and
Xia, 2015). The analysis revealed potential cost savings exceeding 68%, due to
the system’s optimal sizing. The hybrid approach allows increased income from the
solar PV energy that is optimally fed to the grid, in a way that maximized the benefits
received by existing RES supporting mechanisms (e.g. feed-in tariffs, premiums).
2.5 Developing a mini-grid from a PVWPS
The installation of PVWPS in rural Africa creates additional opportunities and trig-
gers further developments in the wider context of rural electrification. Building on
the modularity feature of the solar photovoltaic technology, the capacity of PVWPS
can be increased in terms of rural electrification strategies. Thus, the resulting
system will be an integrated mini-grid and solar pumping system, that covers both
electricity and clean water needs. In most of the cases the mini-grid systems have
to rely on quite a sizeable back-up system i.e. battery storage, in order to meet the
fluctuation in the local demand. Despite the continuous rapid decrease of chemical
storage cost (see section 5.2), in today’s mini-grid systems the battery system is
still an expensive part of the system, representing 50% of the overall cost.
Solar PV mini-grids that only cover residential electricity consumption gener-
ally face increased fluctuation of demand over time. This results in a disproportional
increase of the related battery size. The addition of a major consumer with a more
regular, predictable and complementary consumption in the mini-grid can decrease
substantially the average cost of electricity produced (e/kWh). An obvious reason
is the economy of scale. Moreover, an anchor consumer could benefit from the
electricity and increase its productivity. At the same time household users would
benefit from the reduced bills, sharing the fixed costs (Szabó et al., 2013). The
water pumping can represent this major consumer in the system: it could allow for
a relatively larger PV array with a relatively smaller battery as pumping will take
place when the residential consumption is low. This would decrease the amounts
of curtailed electricity and flatten the system demand curve. Considering that the
main consumption sector of the clean water is the agricultural one, it appears that
PVWPS provide an integrated solution that is on the core of the water-energy-food
nexus targets.
2.6 PVPWS in front of the water and energy African challenges
As far as the water sector is concerned, water extraction is needed for specific peri-
ods that correspond to the irrigation season. Moreover, solar/conventional pumps
are generally designed to meet the peak water demand of just 30%-40% of the total
irrigation season (SNV, 2014). Thus, during at least half of the irrigation season and
the rest of the year, the systems could be partially utilised for other applications.
Since in Sub-Saharan Africa more than 621 million citizens lack access to mod-
ern energy services, it is obvious that excess solar PV output should cover house-
hold and productivity needs. Even a relatively small electricity output could trigger
a significant improvement in the life quality of the local population. Lighting, clean
cooking services and use of refrigerators are simple examples of services that ben-
efit the local population health, quality of life and overall welfare. The latter could
be seen as positive “side effects” of PV-based water pumping systems. Besides,
the per-capita electricity consumption is SSA is at such low levels3that the need
for capacity additions is urgent. A PVWPS can, thus, act as the initial point where a
mini-grid will be formed and through continuous expansions will provide complete
energy services to rural SSA communities. Expanding the services provided by a
PVWPS improves the capacity utilisation and the project’s economic viability. It also
provides additional flexibility on the optimum sizing methodology and the avoidance
of electricity curtailment (Kaldellis et al., 2009).
The PV competitiveness analyses (Szabó et al., 2013, Moner-Girona et al.,
2016a) based on stand alone or mini-grid systems have clearly indicated the ad-
vantages of solar PV systems in West Africa. The displayed Figure 6 is the result of
GIS-based, spatial analyses and illustrates the calculated production cost of elec-
tricity, by processing PV module and diesel prices. Orange and red areas indicate
areas where it is cheaper to produce electricity from PV rather than diesel gensets,
while in areas in blue diesel gensets are the economic option. Identifying priority
PVWPS projects could be the next research task by combining these delineated ar-
eas with high irrigation needs and potential for which there are already available
spatial data (JRC, 2017b).
3According to 2014 World Bank data, the SSA per capita consumption is 483 kWh per
year, compared to the EU average of 5909 kWh. More information is available online at:
Figure 6: Competitiveness mapping of PV and diesel genset based electricity in West Africa. Source:
(European Commission, Joint Research Centre, 2017b)
3 The Energy dimension in the WEF interactions in Africa
3.1 Renewable energy in West African Countries: State of art and
CO2emissions in West Africa have increased by 68% over the period 1990–2015,
reaching 139 Mt CO2-eq. Sharing in 2015 almost 54% of fossil fuels for electricity
in West Africa, Nigeria is responsible for more than 62% of CO2emissions in the
region. Nigeria’s CO2emissions rose by 26% over period 1990–2015. Ghana’s
contribution reached almost 11% in 2015 and Côte d’Ivoire contributed with 11%.
Over the period 1990–2015 the fastest increase of CO2emissions was seen in Benin,
almost 15 times higher.
Figure 7: CO2emissions in West Africa 1990–2015 (left); countries contribution 2015 (right).
Source: (JRC, 2017a)
The Economic Community of West African States (ECOWAS) Renewable En-
ergy Policy was adopted by the 43rd Ordinary Session of the ECOWAS Authority of
Heads of State and Government in 2013. This renewable energy policy aims at
ensuring increased use of solar, wind, small-scale hydropower and bioenergy for
grid electricity supply and the provision of access to energy services in rural areas.
The interest in clean energy in small-scale based on the use of locally available
renewable energy sources —such as solar, wind, hydropower and bioenergy— is
growing in West Africa with at least 268 systems already operational. The lack
of clear policy and regulatory instruments is, still today, the primary barrier to
renewable energy’s large-scale deployment. A tariff structure for the energy sector
is applied in Senegal in 2014, and then extended to every West Africa country in
2016 (ECREEE, 2017).
The West Africa region has set a target to increase the share of renewable
energy in the region’s overall electricity mix to 10% in 2020 and 19% in 2030.
This will lead to a capacity of solar, wind, small scale hydropower and biomass at
2425 MW in 2020 and 7606 MW in 2030. Including large hydropower, the share of
renewables would reach 35% in 2020 and 48% in 2030. Around 25% of rural West
Africa population will be served by mini-grids and stand-alone systems by 2030
(Hyacinth Elayo, 2017).
Benin has planned a 37% renewable energy penetration in 2025. It aims to
reach 150 MW installed capacity; Cape Verde projects to reach 100% of renewable
electricity in the grid in 2020; including large hydropower Gambia wants to reach
35% of renewables in the grid in 2020 and 48% in 2030; Ghana has planned 10%
penetration of renewable electricity in the grid by 2020; Niger has set the target
of 20% renewables in the grid by 2020; Nigeria’s plan projects 18% of renewables
capacity by 2020 and 20% by 2030; Senegal plans to reach 15% of renewables
penetration by 2020 (Hyacinth Elayo, 2017). Liberia planes to reach 20% share of
RES in electricity mix in 2020 and 40% in 2030.
Figure 8: Renewable electricity installed capacity in West Africa broken down by source, 2020 and
2030. Source: ECOWAS Regional Centre for Renewable Energy and Energy Efficiency (ECREEE).
In West Africa the electricity has traditionally been provided through hydropower
that is the most well established and widely used technology in the region. As of
end-2015 an aggregated 5.2 GW of grid-connected renewable installed capacity ex-
ist in the West Africa region, accounting for approximately 15% of the Africa’s total
renewable electricity installed capacity4.
Nigeria is the leader in the region hydropower capacity with 2 GW installed
by 2015. Ghana followed with a total of 1.6 GW. Additional hydropower capacity
is installed in Côte d’Ivoire (604 MW), Guinea (368 MW), Mali (126.8 MW), Togo
(65.6 MW), Sierra Leone (56 MW), Burkina Faso (29 MW), Liberia (4.6 MW) and
Benin (2 MW).
By the end of 2015 a total of 28 MW of wind power (totally onshore) has been
installed in the West Africa region, equal to 0.8% of total wind capacity installed in
Africa. Most of the region’s wind capacity is located in Cape Verde, 25.5 MW. The
rest, 2.2 MW of wind power are installed in Nigeria.
A total of 58 MW of solar photovoltaic capacity is found in the region by end of
2015. Nevertheless more than half of this capacity is on self-generation or off-grid.
Cape Verde is the leader in solar photovoltaic capacity in the region, with 10 MW
followed by Ghana with 2.5 MW.
The biomass capacity used for electricity production in West African countries
in 2015 was estimated at 57 MW, equal to 5.2% of biomass capacity installed in
Africa in the same year. The biomass is almost totally solid biomass. Only a capacity
of 0.3 MW for biogas is found in Burkina Faso.
In 2016 more than 8% (62 TWh) of electricity in Africa is produced in West
Africa. Hydropower shares 25% of electricity production in West Africa in 2016,
higher than the share this technology has in electricity production in Africa. In the
same year fossil fuels dominate the electricity production in West Africa with a share
of 74%, slightly lower than the share these fuels have in the electricity production
in Africa. The contributions of solar, wind and biomass counted altogether for only
1% of the electricity production in 2016.
4Renewable installed capacity data are sourced from (IRENA, 2017)
Figure 9: Electricity production in Africa (left) and West Africa (right) broken down by source, 2016.
Source: Africa Energy Statistics, 2017 (Africa Energy Commission, 2017).
Renewable electricity production in West Africa reached 17.5 TWh in 2016,
equal to 11% of renewable electricity production in Africa and 28% of electricity
production in the region. More than 96% of 2016 renewable electricity in West
Africa came from hydropower. The rest was solar and wind (2.1%) and biomass
and waste (1.5%).
Figure 10: Renewable electricity in West African countries, 2016. Data source: Africa Energy
Statistics, 2017 (Africa Energy Commission, 2017), Map: Authors’ compilation.
Ghana and Nigeria shared respectively 35.6% and 35.3% of renewable elec-
tricity production in West Africa in 2016. Almost 37% of renewable electricity from
hydropower is originated in Ghana followed by Nigeria (36%). Côte d’Ivoire shared
more than 37% of renewable electricity originated from solar and wind power in
2016 followed by Nigeria (25%) and Cape Verde (11%). Renewable electricity
from biomass and waste is originated mainly from 3 countries: Côte d’Ivoire (44%),
Senegal (27%) and Mali (22.7%).
All West African Countries have submitted their Nationally Determined Con-
tributions (NDCs). 9 countries (Benin, Burkina Faso, Cape Verde, Guinea Bissau,
Niger, Nigeria, Senegal, Sierra Leone and Togo) have developed a national renew-
able energy action plan (NREAP). Other countries have developed their sustainable
energy plans (SE4ALL). Table 1 illustrates the existence of the NREAPs in the West
African countries, the year of submissions of their NDC’s and the commitments that
these countries have set in their NDC’s in regard to renewable energy.
Figure 11: Renewable electricity from solar and wind and the countries contribution, 2016.
Table 1: West African countries NREAPs & Nationally determined Contributions
Country NREAP NDC Year Commitments for Renewable Energy (RE)
Benin Y Y 2017 Promote the construction of 95 MW solar,
335 MW hydropower & 15 MW biomass plants.
Burkina Faso Y Y 2016 Doubling the share of RE in the energy mix
Cape Verde Y 2017 Achieve 100% grid access by 2017 and a 30%
RE penetration rate by 2025.
Côte d’Ivoire Y 2016 42% of RE in electricity mix by 2030
Gambia Y 2016 Reach 78.5 Gg CO2reduction by 2025 with RE
and energy efficiency projects. Establish so-
lar 55 mini-grids with an average capacity of
100 kW; Scale up the 200,000 solar home sys-
tems for lighting in urban and selected non-
electrified rural households
Ghana Y 2015 By 2030 scale up RE penetration by 10%: In-
crease small/medium hydro by 150-300 MW,
wind by 50-150 MW & solar by 150-250 MW
Guinea Y 2016 Produce 30% of energy with RE (excl. fuel-
Guinea Bissau Y Y 2015 80% RE in the national energy mix by 2030
Liberia Y 2015 Raise share of RE to at least 30% of electric-
ity and 10% of overall energy consumption by
Mali Y 2016 Large scale deployment of renewable energy.
Install over 100 MW of RE. Reach the target of
10% of RE in the energy mix by 2020, expand-
ing PV, wind, small hydro and biomass energy
Niger Y Y 2016 Increase installed capacity from 4 MW (2010)
to 250 MW (2030), of which 130 MW hydro-
electric Kandadji and 20 MW from wind power
(0.035 MW currently). Doubling the rate of RE
to 30% in primary & final energy balances
Nigeria Y Y 2017 31 million tons potential GHG reductions per
year in 2030 by the use of RE measures.
Senegal Y Y 2015 Solar PV 160 MW. Wind power 150 MW. Hy-
dropower 144 MW
Siera Leone Y Y 2016 Expanding clean energy use (e.g. solar,
mini hydro, LPG, biomass stoves etc), biofu-
els (sugarcane, corn, rice husk) and agricul-
tural and urban waste-to-energy incineration
Togo Y Y 2017 Promotion of efficient/sustainable biomass in
households and solar-based electricity. RE to
4% of the energy mix
4 The Water dimension in the WEF interactions in Africa
Large areas of SSA often suffer from long arid periods that have catastrophic impact
to the agricultural and production and the livestocks. Therefore the large rural
areas, where such activities take place, are in acute need of clean and continuous
water supply not only for drinking, but also for agricultural and other productive
uses (Kougias et al., 2014b). Indicatively, a recent study in the central regions
of Nigeria (Cloutier and Rowley, 2011), showed that rural areas receive less than
6 mm of rain between November and February every year. Accordingly, the main
water resources in these regions are surface waters, streams and open wells that
are often located at a considerably long distance from consumption. More important
is the fact that these resources eventually dry up in the dry months, leaving the
communities without access when water is mostly needed.
With surface water becoming scarce, groundwater is the only alternative tak-
ing also into account water quality issues and the contamination of surface water. As
already mentioned in section §2.1, rural communities often have significant ground-
water resources and, thus, boreholes can be a sustainable solution for clean water
supply. The potential for well extraction generally is located in rural areas, far from
the national grid, with important groundwater quantities at shallow depths. The
use of hand pumps is a common approach in SSA to extract shallow groundwater
for residential use and several initiatives have promoted its use. Well known is the
example of the Afridev5hand pump that effectively supplies water to communities.
However, a hand pump cannot supply significant water quantities, even if the bore-
hole is able to provide much larger discharge. Therefore, they are not suitable for
irrigation and/or extraction from deep wells.
Figure 12: A solar-powered water supply system for livestock. Source: TopSun pumps
5More information is available online at: http://www.rural-water-
PVWPS can be extended from agricultural activities also to act as alternatives
for improved livestock watering systems. In such applications PVWPS keep every
advantage of irrigation systems, including that of the mobility that has a particular
interest. This explains the existence of companies that provide solar pumping ser-
vices on demand/periodically in Africa. In the United States of America this practice
was already a cost-competitive alternative to grid extension since the 90s. Applica-
tion extend from fixed units also to mobile units, that can be transported from place
to place, according to the needs. The latter allow also the creation of an additional
business where lease options or water-as-a-service is provided (Van Campen et al.,
2000). Figure 12 illustrates a fixed PVWPS that fills a water tank for cow-breeding
in South Africa.
4.1 Importance of irrigated agriculture in SSA
African institutions and research organisations with good knowledge of the real
needs of SSA regularly underline the need to provide solutions that promote pro-
ductivity and economic growth, rather than simply mitigating the challenges of wa-
ter, energy and sanitation access. Increasing productivity in the agriculture and
livestock sectors is crucial for rural Africa, with the majority of the citizens work-
ing in these sectors. Indeed, it is widely accepted that approaches leading to im-
proved productivity are effective ways to fight poverty (Sustainable Development
Goal #1 (UN, 2015)) and trigger economic growth. According to (UNEP, 2012) ev-
ery 10% increase in the farms yield leads to an estimated 7% reduction in poverty
in Africa. Accordingly, promotion of irrigation —with a particular focus on irrigation
of smallholders— is cited as a strategy for poverty reduction, climate adaptation,
and promotion of food security (Burney et al., 2010).
In SSA approximately 95% of the farmed land is rain-fed and solely relies
on seasonal precipitation for the crops’ water needs (IWMI, 2012). According to
the Food and Agriculture Organization of the United Nations (FAO, 2017b), irriga-
tion contributes 40% of the total crop production globally, utilizing just 20% of the
global cultivated area. SSA hosts the greatest unexploited potential for irrigated
agriculture globally if both land and water resources are taken into account. More-
over, irrigation improves crop yields by three or four times over rain-fed agriculture
(Van Campen et al., 2000) and it is very important to food security: in West Africa,
Burkina Faso is an indicative example where irrigated fields produced 10% of the to-
tal production (2010) although they represent just 1% of the cultivated area (FAO,
Thus, there is an urgent need to increase the percentage of irrigated crop
production in SSA, especially considering that local climatic conditions in numer-
ous African countries allow various cropping cycles in a year, making a significantly
larger cropping intensity possible. PVWPS can facilitate access to groundwater re-
sources and eventually improve livelihoods (access to clean water, food, health),
increase productivity and income, and increase the overall social welfare (poverty
alleviation, noise and emissions reduction).
PVWPS systems use is not limited to groundwater resources and can also be
used for the extraction of surface water in canals, streams or lakes. Strategies to
increase the share of irrigated areas will certainly involve providing access to energy
and investments on energy infrastructure. On the other hand actions to mitigate
energy poverty in SSA and provide access to modern energy to rural SSA, do not
necessarily provide access to clean water. This is observation reveals that even if
farmers gain access to modern energy (e.g. by grid extension), a large proportion
will continue to rely on seasonal rains for irrigation due to the specific bottlenecks
related to diesel pumps. Moreover, an initial investment to a genset involves a
commitment to re-invest for fuel and O&M, annually.
4.2 Small-scale farming in SSA
Challenges related to the food dimension of the WEF nexus refer not only to families
that lack the means to purchase food, but also have neither the means to produce
it. For them access to irrigation water is a key to produce crops, create income and
eventually become food secure. In West Africa the major source of income for the
70–80% of the population is related to crop production, exports and food supplies
(Toulmin and Guèye, 2005).
In SSA the majority of land-holdings is small, a feature that is likely to become
the status quo considering the increasing population. Plans to support advanced
practices need to be tailored to the local conditions in order to secure a successful
introduction of irrigation. Table 2 presents the outcome of a survey (Masters et al.,
2013) on the average size of farms and the ownership pattern (hectares per capita)
involving six SSA countries6. Overall, an analysis on 1211 family farms in Eastern
and West Africa (183 female-headed and 1028 male-headed) showed an average
land area of 1.1 ha (2.8 acres) for the female-headed and 2.8 ha (5.4 acres) for
the male-headed cultivated land (Shah et al., 2013).
Table 2: Land ownership and distribution among smallholder farms in selected SSA countries.
Source: (Masters et al., 2013)
Year Sample Mean farm Farm size Land (ha)
Country of survey size size (ha) (ha/capita) per household
Kenya 1997 1146 2.28 0.41 0.55
Kenya 2010 1146 1.86 0.32 0.57
Ethiopia 1996 2658 1.17 0.24 0.55
Rwanda 1984 2018 1.20 0.28
Rwanda 1990 1181 0.94 0.17 0.43
Rwanda 2000 1584 0.71 0.16 0.54
Malawi 1998 5657 0.99 0.22
Zambia 2001 6618 2.76 0.56 0.50
Mozambique 1996 385 2.10 0.48 0.51
Generally, most of the fields are cultivated by farmers living in the vicinity of
the field. Usually every field is cultivated by a family in a household enterprise, that
resides at a house inside the limits or near the field. Family farming is dominant
in Africa as it succeeded and displaced colonial plantations, collective farms, and
state-owned farming operations (Masters et al., 2013). In West Africa farming
has remained overwhelmingly in the hands of smallholders until presently. The
autonomy and flexibility of family enterprises is an advantage against difficulties
and helps them adapt to emerging economic opportunities (Toulmin and Guèye,
2005). However, family farming faces a challenging future as local markets and
food systems become increasingly globalized and need new instruments to continue
playing its important role.
6For Kenya and Rwanda data have been collected in different years, showing the progressive decline
of the average farm size.
Already in 1994 Vaishnav (Vaishnav, 1994) raised the inherent challenges that
simplistic approaches to irrigation bring in Sub-Saharan Africa. The common —in
the 1990s— assumption that where land and water are available irrigation would
be feasible, proved to be over-simplistic as it ignores important dimensions such as
the energy, environmental, as well as socio-economic and policy factors. Foreseeing
the WEF nexus solutions, Vaishnav proposed a multidisciplinary approach to make
any attempt efficient, productive and sustainable, involving the local communities.
PVWPS are particularly compatible to this formation as they are very efficient
for irrigating relatively small fields. They are more suitable for low- and medium-
head water pumping, because in cases of greater hydraulic head requirements,
their discharge rate decreases. Equally important, PVWPS favour modern irrigation
technologies such as drip and micro irrigation. This shows that a transition to solar-
based irrigation could allow SSA leapfrog the phase of use of sprinkler systems and
directly adopt best practises.
4.3 Drip and micro irrigation
Drip and micro irrigation systems provide the water drop-by-drop near the plant’s
root system and through a lateral pipe connected to the main line that is —directly or
indirectly— fed by the pump. Drip systems involve high efficiencies as they minimize
the water losses due to evaporation by 40–80%, because the water flows directly
to the root zone. In such low-pressure constant or daily irrigation techniques, the
water quantity that flows to the plant takes nearly the exact rate of water usage by
the plant, making the water storage properties of soil less important. It is a very
efficient mechanism for delivering water along with fertilizers, if needed. Not only
it increases yields, but also allows planting high-value crops in regions where they
could not be sustained by rainfall alone: This is particularly important for farmers,
as it increases their income and allows for production of market vegetables even
during the dry season. Drip systems also eliminate deep percolation that appears
in flood techniques and increase the yield minimising the moisture stress (Pande
et al., 2003). Indeed, flood irrigation or the use of sprinklers are largely responsible
for challenges related to soil degradation.
Figure 13 illustrates a solar-powered drip irrigation system. The PV array pow-
ers a submersible pump (or a surface pump, depending on the water source), that
extracts groundwater through a borehole and feeds it to an elevated tank during
the day. Then, the tank distributes the water with gravity to the low-pressure drip
irrigation system. This configuration uses no batteries and the operation of the
pump is limited during the daytime. The fertilizer injector also allows adding fertil-
izer directly to the water and applying it consistently throughout the drip system.
This expedient reduces the fertilizer waste and minimizes its cost for the farmers.
It is important to note that solar-powered drip irrigation kits are already avail-
able in the SSA market, where the application of drip irrigation is rapidly expanding
in Sub-Saharan Africa (Burney et al., 2010, FAO, 2017b). PVWPS are particularly
suitable for drip irrigation because of the jointly provided water- and energy-saving
approach, combining the efficiency of drip irrigation with the high reliability of the
PVWPS technology. Solar pumps’ favourable conditions require medium depths of
pumping (50m), with total pumping head ideally being less than 75m (Mcsorley
et al., 2011).
Recently, in 2013, an extensive survey of application of drip irrigation in SSA
(Friedlander et al., 2013) analysed >60 installations and revealed that the transition
Figure 13: Typical configuration of a solar-powered drip irrigation system. Source: SunCulture
to modern irrigation practices saves labour and improves water use efficiency. It is
interesting to note that although higher yield is the most frequently cited advantage
of drip irrigation, in the case of SSA it was cited in only half of the installations. This
is probably due to the lack of fertilizers and experience, resulting in yields similar to
those of surface irrigated fields. Drip systems appeared to be highly reliable in SSA,
only having few notable technical issues related to lack of expertise. The study also
underlines the farmers’ willingness to continue using drip irrigation and the need
to address complementary technologies —such as access to energy— to facilitate
successful use of drip irrigation adoption in SSA.
4.4 Water storage and its opportunities
As illustrated in Figure 13, PVWPS often incorporate a water storage facility, usually
a water tank. The tank has a multiple role: It improves the stability of the pumping
operation as it provides continuous flow of water to the piping system with constant
flow rate and steady pressure. At the same time it enables irrigation during the
night or in cloudy days, acting as an indirect energy storage; energy produced by
the solar array is used to pump water and store it for later use, when energy will
not be available. Water storage in a PVWPS plays a role similar to the one of battery
storage, with the electric power load demand being replaced by water demand. This
electric power load demand represents the energy needed to pump the required
volume of water to the storage tank. If the water needs vary throughout the year,
one has to be conservative and use the highest amount that one expects to use
(Al-Smairan, 2012).
This leads to the advantageous characteristic of the PVWPS configuration of
Figure 13, a PV pumping system that does not need a battery for back-up. Using
a water tank for storage reduces the required investment and maintenance costs
and increases system reliability. Water tanks or reservoirs already in place can
also be used, further reducing the initial investment. Water tanks also have a cost
which increases linearly with their volume. Thus, in the literature it is suggested
that water tanks should have the capacity to cover the irrigation needs of two days
(Cloutier and Rowley, 2011), or at least two to three days (Al-Smairan, 2012).
The concept builds on the idea to store water than electricity in batteries and
accordingly reducing the overall cost and complexity of the system. However, if
the water requirements are high and non-efficient irrigation methods are selected
the size and cost of storage tanks may become prohibitive. An extreme example
is provided in (Campana et al., 2015), where peak irrigation water requirements
(IWR) equal to 70m3/ha/day would end up in a storage capacity of 210m3/ha in
order to secure autonomy of three days. Such a large capacity may involve a cost
as high as US$ 25,000/ha (Díaz-Méndez et al., 2014), which is an extreme case,
with high IWR and non-efficient use of the water resource. Typical plastic water
tanks can reach a volume of 35m3which may be sufficient to irrigate 5 hectares
for 2 days. Still, in large fields or water-intensive crops, alternative solutions such
as battery storage or hybrid systems might be the optimal choices. In such cases
a techno-economic analysis that uses optimization and artificial intelligence can
support planning.
4.5 Type of pumps
Every pump operates at a combination of flow and hydraulic head (pressure). Typi-
cally, given a power input, maximum flow is reached under low-head requirements,
while low discharge is given in high-head applications (Chandel et al., 2015). There
is some evidence that PVWPS can not attain very high flows and/or extract very deep
(>100 m) groundwater as needed in some places (Granich and Elmore, 2010). Con-
trary to that, other sources mention that solar pumps have the potential to pump as
deep as 200 m and reach production of up to 250 m3/day (2.9 lt/sec). Currently
there exist companies that produce pumps specifically made for water pumping
powered by renewable energy sources. Such pump motors can be powered either
by alternating (AC) or direct current (DC) power, thus pumps can be directly cou-
pled or with the use of an inverter. According to their application, solar pumps are
distinguished in three different types: submersible, floating and surface pumps:
Submersible pumps
- Centrifugal pumps
- Helical pumps
Floating pumps
Submerged pumps with surface motor
Submersible pumps (see Figure 14, (Practical Action, )) are usually centrifugal-
type pumps installed underwater, including the motor. Both the motor and pump
are grouped and the system consists of a water-proofed electric motor and a pump,
in a single unit. Submersible solar pumps are generally used to extract groundwater
from depths as high as 200 m. They can also be placed in surface water resources,
provided sufficient water depth. In the market there exist both DC- and AC-powered
submersible solar pumps, therefore they can either be directly-coupled to the solar
modules, powered by batteries, or be connected to an AC power source. In the
case of brushed DC motor use, the equipment will need to be dismantled approx-
imately every two years for maintenance and brushes’ replacement. During the
past two decades there were technological advances and breakthroughs in helical
motor pumps’ design (Chandel et al., 2015). Such pumps are positive displacement
pumps, submersible, have the ability to operate smoothly for many years and are
powered by similar motors as those for centrifugal pumps.
Floating pumps (see Figure 15) usually have a submersible pump suspended in
the water below the float, that is anchored in e.g. a pond. Similarly to submersible
ones, the motor and pump are grouped in a single unit. The water is pumped
through a tube to the irrigation system. Floating pumps have the advantage of
easier installation, especially for pumping from a pond, lake, or slow river. Surface
solar pumps are used to draw water from streams, lakes or ponds, springs, storage
tanks and shallow wells. Although they generally cannot lift water from depths
larger than few meters (5–10 m), they are suitable solutions for conveying the
water over relatively long distances.
Figure 14: Submersible pump Figure 15: Floating pump
Figure 16: Submerged pump with surface motor
Submerged pumps with surface mounted motor (see Figure 16) have the ad-
vantage of easy access to the motor for brush changing and maintenance. DC
motor with brushes requires frequent maintenance and the cost and maintenance
problems of DC motors have resulted in the use of induction motors that add an
inverter. Submerged pump with surface motor were widely installed with turbine
pumps in the West Africa during the 1970s (Practical Action, ). However, the low
efficiency of this configuration due to power losses and the high cost of installation
have led to its replacement by the submersible type.
Solar pumps market
Since the first installation of PVWPS in 1978 (Barlow et al., 1991), the market has
grown with studies indicating more than 10,000 PV pumps in operation by 1994
(Narvarte et al., 2000). A recent market report (MRF, 2017) mentions that the
global PVWPS is expected to grow by around 5.6% in terms of turnover, during the
period 2017–2023. Looking forward, the global solar pump market is expected to
reach over 1.5 million units by 2022 compared to approximately 120,000 units in
2014, representing a twelve-fold increase in market size (Technavio, 2016).
For 2015, approximately 63% of the market share was targeted for irrigation
and the agriculture industry segment. It is expected that the demand for solar
pumps will continue to increase. This is mainly due to the initiatives by emerging
economies such as India and China to promote sustainable development.
However, in term of solar module capacity the PVWPS market is detrimental.
The global cumulative power capacity of the solar modules installed in PVWPS is
few hundreds of MWp, representing less than 1hof the solar PV installations for
grid connected power production.
The key players of the global solar water pumps market are (Technavio, 2016):
Lorentz (Germany)
SunEdison (USA)
Tata Power Solar Systems Ltd. (India)
Shakti Solar Pumping System (India)
Wenling Jintai Pump Factory (China)
Bright Solar Pvt. Ltd. (India)
While, other prominent vendors include the following companies (Technavio, 2016):
• Conergy
CRI Group
Dankoff Solar
• Flowserve
Greenmax Technology
• Grundfos
Irrigation Systems
5 Suitability of solar-powered water extraction in Africa
5.1 African solar resource potential
The existing solar potential in large parts of Africa is among the highest in the
world. Despite the fact that the solar insolation reaching West Africa is slightly
lower than that of the north African countries, it is still much higher than that of the
south European countries (Huld et al., 2012). This is also illustrated in Figure 17,
where the photovoltaic solar electricity potential in Africa is depicted on a continental
scale (European Commission, Joint Research Centre, 2017a). Apart from being
abundant and non-depletable, solar is also a non-polluting resource, with a very
low environmental impact that aligns with the recent global climate targets.
Figure 17: Solar electricity potential in Africa Source: (European Commission, Joint Research Centre,
Detailed country maps for all African countries are available at the online por-
tal of the JRC (European Commission, Joint Research Centre, 2017a). The avail-
able maps and Figure 17 illustrate they yearly sum of global irradiation on an opti-
mally inclined surface and they represent collected and processed data of the period
5.2 Economics of solar photovoltaic technology
The recent drops of the solar module prices made PVWPS economically attractive, as
their installation cost is related to that of a main component i.e. the solar modules.
Between 2008 and the end of 2012, there was observed a drop in module price
as high as 80%, 20% in 2012 alone (Jäger-Waldau, 2017). Figure 18 shows the
decreasing cost of solar PV module over time. Naturally, the cost of PVWPS did not
shrink by the same amount during the mentioned period, as the solar module is only
one part of the system and the remaining parts are at higher level of technological
and market maturity. Still, the PVWPS systems are expected to keep following the
lowering of module prices, but at a slower pace.
Figure 18: Price-experience curve for solar modules Source: (Jäger-Waldau, 2017)
Solar pumping technology has continuously improved since its first appear-
ance. While in the early 1980s the typical solar energy to hydraulic (pumped water)
transformation efficiency was at the level of 2%, it reached 9% by 2010 (Maupoux,
2010). This followed the technological breakthroughs in solar photovoltaic manu-
facturing, with the average commercial module efficiency continuously increasing
(between 2010 and 2017 it achieved an additional 2% increase in efficiency). Even
more important is the increase of the reliability of the solar technology. It is widely
accepted that current PV systems are far more reliable than in early days (Chandel
et al., 2015). Currently the weakest part of a PVWPS is the pump and an efficient
and reliable pump will offset the requirements for over-sizing the array, resulting
in cost reductions.
A 2010 study showed that the investment costs of PV systems are still much
higher than those of gensets (Qoaider and Steinbrecht, 2010). However, if lifetime-
cycle cost is considered PV systems are found to be more economically attractive
as compared to diesel based pumping systems, since few years. Already in 2013
a report for PVWPS in India estimated the payback period at 4 years, with a lev-
elised cost of energy (LCOE) equal to US$ 0.141/kWh compared to US$ 0.228/kWh
for similar diesel-based systems (Pullenkav, 2013). Similarly to renewable-based
electricity production, high investment costs are the major barrier for implement-
ing solar-based pump projects. This issue is particularly important in developing
countries due to the lack of financial capital as well as its higher cost.
5.3 Economics of battery storage
During the last years battery storage technology also experienced significant tech-
nological breakthroughs. The learning rates of these technologies were accelerated,
followed by continuous drop on their cost. This encouraged those involved in the
sector of clean, sustainable energy sources to foresee an important future role for
lithium-ion batteries. In that sense future, low-cost batteries will boost the tran-
sition to unprecedented high share of RES with storage in the energy mix over
conventional generators.
The results of a recent research revealed an even quicker drop in the battery
cost (Kittner et al., 2017). The analysis included the development of a model that
integrates the value of investment in materials innovation as well as the effect of
technology deployment over time. The results of the simulation of empirical data
have shown that the price of electric energy storage battery packs will drop from US
$ 202.88/kWh (2016) to US $ 124.24/kWh (2020). In case such a cost reduction
is achieved in such a short time-frame, it will boost PVWPS installations.
5.4 Initiatives for PVWPS deployment in developing countries
The viability of PV pumping systems has been evaluated already in the 1970s. Since
then several actions, initiatives and supporting schemes have been developed to
promote their widespread use. As already pointed, an important challenge that
PVWPS face is is the comparably higher cost to conventional approaches. High initial
cost requires access to finance, which is particularly limited in developing countries.
Access to technology and the capacity to operate and maintain the systems needs
also to be improved as it still lacks the experience and know-how on diesel-base
systems, operated for decades.
Specifically, the first attempt to assess SPWPS applicability was the 1978 pro-
gram known as “Global Solar Pumping Project”. It included twelve pumping systems
in Mali, Sudan and Philippines in 1980, with approximately half of the systems op-
erating as planned. The second phase of the program supported the installation of
additional 64 systems with improved specifications and improved performance, but
still requiring further R&D to reliability (Chandel et al., 2015).
Naturally the huge technological progress of the next four decades allowed
for large-scale installations. This has been the result of governmental policies to
transition towards PVWPS. It is also due to the technology’s benefits in terms of
socio-economic, energy security, and environmental protection. Throughout the
world, there are pilot projects for irrigating crops by photovoltaic pumps and gen-
erating electricity to add national grid. In India the number of installations during
the 1992–2014 period was 13,964. Additional 17,500 solar-powered pumping sys-
tems were expected to be installed in 2015 with the ultimate goal being to reach
100,000 PVWPS for irrigation by the year 2020. Other countries that have set
specific targets include Bangladesh with a target of 50,000 systems by 2025 and
Morocco that aims at reaching 100,000 installations by 2022 (IRENA, 2016).
Recently in 2016 the World Bank has developed an accessible and interac-
tive Knowledge Base on Solar Water Pumping7. This online repository provides
information to all interesting parties such as policy makers, scientist, developers,
entrepreneurs etc. It aims to cover the knowledge gap about the technology and
7Available online at:
provide resources that promote its wider deployment. It also provides to more than
260 real-world applications from all regions, supported by the World Bank. It is in-
teresting to note that almost half of the projects (125 out of the 260) have been
implemented in SSA.
5.5 Solar-powered water extraction in W. African climate policies
5.5.1 The ECOWAS Renewable Energy Policy
Differently from other solar-based technologies (e.g., solar water heating), the
ECOWAS Renewable Energy Policy (see section 4) does not foresee any specific
target for renewables penetration in water pumping. Nevertheless, the document
strongly emphasizes the need for increasing the use of solar-fed appliances for
off-line and small scale applications and water pumping and irrigation are cited as
a “productive uses of renewable energies” triggering social and economic develop-
ments. It is worth noticing that water pumping, together with electricity production,
is also cited as a possible application of raw locally produced vegetable oils (e.g.
5.5.2 West African Nationally Determined Contributions (NDCs)
Even in NDC of single countries West African countries, the solar or renewable
based water pumping is seldom mentioned, with the sole exception of Cape Verde
under that, among its general mitigation actions includes the “further promoting the
use of smaller distributed energy solutions (e.g. solar pumps) for water pumping,
distribution and irrigation”.
Nevertheless, solar-based technologies do have their place in the overall NDC,
especially on a household dimension and one could guess that solar based pumping
and irrigation finds its place under such a more general umbrella. For instance,
Nigeria NDC intends to “work towards an installed Off-grid solar PV capacity of
13 GW” while Togo foresees the general promotion of solar technologies for house-
hold scale needs. Sierra Leone intends to promote “the expansion of the energy
mix through uptake of renewable energy sources (solar, wind, hydro, biomass)
particularly in the rural areas”.
Senegal aims at using solar for electrifying quite a consistent number of vil-
lages (392 in the unconditional NDC and up to 5000 in the conditional version8),
where it can be supposed that such an electrification will be designed not only with
lighting in mind, but also targeting wider needs such as electric appliances and,
indeed, water pumping.
8Some of the INDCs include an unconditional mitigation component alongside an enhanced con-
ditional one. Most of the conditional components relate to the provision of finance, technology or
capacity-building support and translate into a percentage increase in the level of effort associated
with the related unconditional component (UNFCCC, 2017).
6 Conclusions
Despite the important steps that have been made in the past few decades, rainfed
food production in Sub-Saharan Africa is still not sufficient to cover the needs,
making local food consumption strongly dependent on imports. Considering that
population increase trends in the region are the highest worldwide, it is certain that
the need to increase the food production (agricultural and livestock) will become an
absolute necessity in the near future. This will put pressure in the available water
resources and will force the transition from rainfed to irrigated agriculture, requiring
require significant amounts of energy. Production growth will only be achieved
by accelerated investment in water and energy infrastructure (FAO, 2008). Such
investments naturally need to range in scale, design and technologies-used to better
adapt to the local conditions and needs (Matinga et al., 2014). Accordingly, solutions
can range from small-scale irrigation systems to larger hydropower facilities that
regulate the water and energy resources in river-basin scale.
Planning policies need to focus on designing systems promoting agricultural
growth and poverty alleviation. Intensification and diversification of the produc-
tion through increasing outputs and economic income will be key aspects. The
ultimate aim is not only increasing the total production and food availability, but
transforming the productivity landscape, particularly in rural areas of SSA. A rad-
ical increase of the efficiency of food production can enable improving the overall
real net income, increase the agricultural employment rate/wages and at the same
time reduce local food prices. Solutions includes modern agricultural practices that
exceed the purpose of the present Technical Report, such as introducing the cul-
tivation of high-value products, building supply- and value-chains for equipment
and products to name a few. Adapting the best available strategies, leapfrogging
outdated practices of the developed world and promoting systems that are resilient
to the local conditions is the way to move forward.
The available potential for improvement is indeed large, allowing —even small-
scale solutions— to have a significant impact. Currently in SSA 95% of the agri-
cultural land depends on “green water” i.e. precipitation and moisture from rain
held in the soil, which in large parts of the continent is lost by evaporation before
generating run-off (Rockström and Falkenmark, 2015). Water losses is a major
challenge particularly in dry tropical regions, as the available field research has
shown that 50 to 70% of rainfall does not reach crops but evaporates or becomes
surface run-off that has the adverse effect of soil erosion (Molden, 2007). It is,
thus, essential to also utilize other water resources in the surface/groundwater and
provide supplemental or exclusive irrigation to improve the currently rain-fed agri-
culture in semi-arid areas of SSA. In such areas where water resources are scarce,
it is also important to guide as much water as possible to the root zone to improve
the yield.
Coping with this challenge is the current major playground for solar-powered
water pumps. PVWPS are ideally suited to small-scale farming, a fundamental
pillar of food security. Moreover, they can extract both surface and groundwater
resources and in extended dry periods can provide the required water to avoid the
devastating effect of dry spells, especially in the crops’ growing, flowering season.
Moreover, PVWPS can be fitted in existing irrigation schemes, as they are generally
compatible to relevant infrastructure.
A crucial point in securing the successful application of PVWPS is related to the
fact that irrigation may be required only in short periods of the year. In such cases
with the demand for water being more variable, PVWPS will need to be over-sized
to meet peak demand and as a result be them under-utilized for long periods. This
under-utilization could in principle favour conventional, diesel-powered pumps that
require a low initial investment over PVWPS. Nevertheless, this particular charac-
teristic of PVWPS creates opportunities: co-operatives to jointly provide water-as-
a-service have already appeared in SSA, using solar-powered pumps. Such prac-
tices allow high utilization of the equipment and address the main the risks of solar
pumping i.e. groundwater over-extraction.
More important, PVWPS can provide the excess solar PV power to supply elec-
tricity to communities for productive or household use. The modular nature of
the solar PV technology and its compatibility and complementarity with other RES
(Monforti et al., 2014,Kougias et al., 2016d) also allows the creation of mini-grids
that provide clean energy to African communities, building on an —initial— solar-
powered scheme. This feature places the solar-based pumping systems at the
edge of the water-energy nexus, becoming enablers for increased energy access.
In such a manner during the non-productive periods when irrigation is not required,
PVWPS will purely act as energy-producing infrastructure. In cases regulated irri-
gation canals exist, solar PV systems can provide the required energy and at the
same time minimize the evaporation water losses (Kougias et al., 2016a). Besides,
large scale solar systems can be combined with existing dams and their installation
on the face of dams (Kougias et al., 2014a, Kougias et al., 2016b) or the vicinity of
the reservoir, to lead to increased efficiencies and optimum scheduling.
The key feature of the analysed solar-powered systems is their modularity:
their size can be increased according to future needs and they can be combined
with conventional or renewable energy systems. Forming mini-grids and steadily
expanding their coverage and service is currently considered a crucial strategy to
provide modern energy to the 620 million African citizens with no access to elec-
tricity, in the rural areas of SSA.
The possibility also for mobile PVWPS systems allows high utilization rates,
supports affordability and creates new business opportunities. More important,
leapfrogging the less-efficient and outdated irrigation technologies that were de-
veloped in the second half of the 20th century, will help avoiding climate implica-
tions. Currently groundwater pumping contributes 8%-12% of all GHG in India
(Shah et al., 2013), while in China the total energy use just for irrigation repre-
sents 50%-70% of the total GHG emissions of the agriculture sector (Zou et al.,
2015). It is therefore essential to support a rapid growth of the agricultural ac-
tivities and the corresponding output keeping in mind the climate implications.This
includes a sustainable management of the available water resources, ensuring that
the required quantities for ecological conservation and groundwater aquifer recov-
ery, are not utilized. Furthermore, the applied solutions need to eventually lead to
an emission-neutral system, where the used technologies have a minimal environ-
mental impact. Solar PV water pumping systems, can potentially constitute such
a technology, if applied with respect to their technical characteristics and limita-
tions. In case their application is successful in SSA, the agricultural sector of the
fastest growing continent will have an asset towards achieving sustainable growth
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List of abbreviations and definitions
AfDB: African Development Bank
CAPEX: Capital Expenditure
EC: European Commission
ECOWAS: Economic Community of West African States
EE: Energy Efficiency
EU: European Union
FAO: Food and Agriculture Organization of the United Nations
FIP: Feed-in-premium
FIT: Feed-in-tariff
FC: Fuel Cost
GHG: Greenhouse gas
GW: Gigawatt
GWh: Gigawatt-hour
INDC: Intended Nationally Determined Contributions
IPCC: Intergovernmental Panel on Climate Change
JRC: EC Joint Research Centre
kW: Kilowatt
LCOE: Levelised Cost of Energy
MW: Megawatt
NDC: Nationally Determined Contributions
O&M: Operation and Maintenance
OPEX: Operating Expenditure
PVWPS: Photovoltaic Water Pumping System
R&D: Research and Development
RES: Renewable Energy Sources
RET: Renewable Energy Technologies
SDGs: UN Sustainable Development Goals
SSA: Sub-Saharan Africa
TWh: Terawatt-hour
UN: United Nations
WEF: Water–Energy–Food nexus
WEFE: Water–Energy–Food–Ecosystems nexus
List of figures
Figure 1. Scoop hole in Turkana district, Kenya. Source: (Stevens, Lucy, 2014) 6
Figure 2. Typical configuration of SPWPS for irrigation with water storage.
Source: (Maupoux, 2010) . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 3. Typical configuration of SPWPS for drinking and livestock water pro-
vision with water storage. Source: (Maupoux, 2010) . . . . . . . . . 8
Figure 4. Block diagram for a stand-alone PVWPS, with an AC motor-pump
system. Source: Authors’ interpretation elaboration on information
provided in (Hansen et al., 2000) . . . . . . . . . . . . . . . . . . . . 12
Figure 5. Hybrid solar PV and diesel generation scheme with battery storage.
Source: (Hitachi Zosen Corporation, 2013) . . . . . . . . . . . . . . . 13
Figure 6. Competitiveness mapping of PV and diesel genset based electric-
ity in West Africa. Source: (European Commission, Joint Research
Centre,2017b) .............................. 15
Figure 7. CO2emissions in West Africa 1990–2015 (left); countries contribu-
tion 2015 (right). Source: (JRC, 2017a) . . . . . . . . . . . . . . . . 16
Figure 8. Renewable electricity installed capacity in West Africa broken down
by source, 2020 and 2030. Source: ECOWAS Regional Centre for
Renewable Energy and Energy Efficiency (ECREEE). . . . . . . . . . 17
Figure 9. Electricity production in Africa (left) and West Africa (right) bro-
ken down by source, 2016. Source: Africa Energy Statistics, 2017
(Africa Energy Commission, 2017). . . . . . . . . . . . . . . . . . . . 18
Figure 10. Renewable electricity in West African countries, 2016. Data source:
Africa Energy Statistics, 2017 (Africa Energy Commission, 2017),
Map: Authors’ compilation. . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 11. Renewable electricity from solar and wind and the countries contri-
bution,2016................................. 19
Figure 12. A solar-powered water supply system for livestock. Source: TopSun
pumps.................................... 20
Figure 13. Typical configuration of a solar-powered drip irrigation system. Source:
SunCulture ................................. 24
Figure 14. Submersiblepump............................. 26
Figure 15. Floatingpump ............................... 26
Figure 16. Submerged pump with surface motor . . . . . . . . . . . . . . . . . . 26
Figure 17. Solar electricity potential in Africa Source: (European Commission,
Joint Research Centre, 2017a) . . . . . . . . . . . . . . . . . . . . . . 28
Figure 18. Price-experience curve for solar modules Source: (Jäger-Waldau,
2017) .................................... 29
List of tables
Table 1. West African countries NREAPs & Nationally determined Contributions 19
Table 2. Land ownership and distribution among smallholder farms in selected
SSA countries. Source: (Masters et al., 2013) . . . . . . . . . . . . . 22
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ISBN 978-92-79-84034-0
... They found that data and information that can be applied to the WEF nexus in South Africa were sector specific. A WEF study carried out in West Africa by [49] aimed to evaluate and provide knowledge on technologies that can harness the renewable energy sources in Africa for supporting water extraction, energy generation, agricultural, and economic development. The advantages of using solarpowered water pumps were compared to the common practice of fossil fuel-based water pumps. ...
The increasing global population leading to increased consumption of finite resources is a major challenge facing the ecosystem. This constraint creates the need for a well-coordinated system for producing a sustainable source of food, water, and clean energy (biofuels) which can be achieved by employing nexus principles. As the Nigerian government has been promoting sugar and bioethanol production from sugarcane in a bid to achieve food and energy security, this study aims to evaluate the water-energy-land-food nexus for the development of bioethanol in Nigeria. To assist this evaluation, indicators—constituting the nexus index—were applied to measure the consumption, mass, and economic productivity of resources. Land productivity was added to the nexus assessment as part of this research. Producing biofuels from crops impacts nexus resources, importantly land and food but also water and fossil energy resources used in the cultivation and processing phase. The nexus assessment helped to show areas of resource use inefficiencies needing possible improvements to move production towards sustainable use of resources. Two sites were studied and both had an average nexus performance; however, the site having modern irrigation used lesser energy leading to a better performance in the water consumption, energy, mass, and economic productivity indicators. This research provides literature as well as quantitative values that can help stakeholders analyse and make judicious decisions (policy) using the nexus system to improve resource management.
... Accordingly, HyPump is at TRL-6 9 . Compared to solar-powered pumps (Kougias et al., 2018), HyPump claims to involves reduced cost by up to 37%. When switching from an electric pump to HyPump the payback is estimated to range between 2.6-3.8 years and have a lifetime of 25 years. ...
Technical Report
Full-text available
Executive summary The present report collects the technological developments of hydropower. It is a deliverable of the Low Carbon Energy Observatory (LCEO) project, a European Commission (EC) project that assesses the technological progress of clean energy sources. It is a follow-up the previous (internal – EC only) LCEO assessment (Kougias, 2016a) and presents important research activities that have taken place in EU and abroad related to hydropower. Since the operation of hydroelectric facilities involves different sectors and scientific fields, efforts of the present report focused on monitoring research and development (R&D) activities that cover the involved sectors. Thus, apart from the purely technological projects, the report covers studies that aim to enable better simulations of hydrological cycle, climate change and its relation to hydropower operation as well as the water-energy-food (WEF) nexus interactions. In addition to projects funded under the Horizon 2020 (H2020), the present exercise screened Knowledge and Innovation Community (KIC)-Innoenergy, InnovFin and the European Fund for Strategic Investments (EFSI) schemes for relevant projects. Moreover, national research councils of countries with a strong tradition in hydropower were analysed and R&D projects supported by national research organisations were identified. This included the U.S. Department of Energy (DoE), the hydropower research organizations of Norway and China and the national research councils of Switzerland and Japan. The identified activities fall into four main categories. Projects on hydraulic design and hydropower mechanical equipment aim at advancing the construction and operational characteristics of hydro stations. This includes advanced materials and computational models to minimise machinery wear. Efforts for increased range of operation and flexibility of hydropower have been consistent for some time now and were identified in both the present and the previous report (Kougias, 2016a). The exploitation of the generally untapped low-head hydropower potential is coupled by advancing the technical characteristics of hydrokinetic turbines. The environmental and ecological characteristics of hydropower plants have been the objective of projects with a special focus on fish population, fish-friendly turbines and the important challenge of securing the required environmental flows that allow ecological conservation. The topics of the remaining large-scale projects are the integrated water resources management, the WEF nexus, hydro-powered solutions for irrigation and advanced climate simulations. Most of these projects have additional aims to hydropower technological advancement; however, their implementation promotes a more efficient and sustainable operation of hydroelectric stations.
Full-text available
Supplying power to remote areas may be a challenge, even for those communities already connected to the main grid. Power is often transmitted from long distances, under adverse weather conditions, and with aged equipment. As a rule, modernizing grid infrastructure in such areas to make it more resilient faces certain financial limitations. Local distribution may face stability issues and disruptions through the year and—equally important—it cannot absorb significant amounts of locally-produced power. The European policy has underlined the importance of energy production in local level towards meeting energy security and climate targets. However, the current status of these areas makes the utilization of the local potential prohibitive. This study builds on the observation that in the vicinity of such mountainous areas, irrigation dams often cover different non energy-related needs (e.g., irrigation, drinking water). Transforming these dams to small-scale hydropower (SHP) facilities can have a twofold effect: it can enhance the local energy portfolio with a renewable energy source that can be regulated and managed. Moreover, hydropower can provide additional flexibility to the local system and through reservoir operation to allow the connection of additional solar photovoltaic capacities. The developed methodological approach was tested in remote communities of mountainous Greece, where an earth-fill dam provides irrigation water. The results show a significant increase of renewables' penetration and enhanced communities' electricity autarky.
Full-text available
Pioneering approaches are needed to accelerate universal access to electricity while simultaneously transitioning to reliable, sustainable and affordable energy systems. In sub-Saharan Africa (SSA), the challenges lie in attracting the private sector to complement public investments. Here, we present an integrated ‘low-hanging-fruit’ approach aimed at boosting private investment and speeding up the deployment of renewable energy systems in SSA. We analyse the potential of existing energy infrastructure, where a significant upfront investment has already been made, to be exploited for electricity generation. We develop a comprehensive methodology to identify and select suitable locations in SSA and estimate their potential for exploitation. These locations have been further analysed in terms of power capacity potential, electricity output, investments needed and population to be benefited. This strategy to attract additional finance can easily be reproduced, engaging private investors while simultaneously helping to achieve the United Nations (UN) Sustainable Development Goals on energy.
Full-text available
This paper describes the status quo of the power sector in Burkina Faso, its limitations, and develops a new methodology that through spatial analysis processes with the aim to provide a possible pathway for universal electricity access. Following the SE4All initiative approach, it recommends the more extensive use of distributed renewable energy systems to increase access to electricity on an accelerated timeline. Less than 5% of the rural population in Burkina Faso have currently access to electricity and supply is lacking at many social structures such as schools and hospitals. Energy access achievements in Burkina Faso are still very modest. According to the latest SE4All Global Tracking Framework (2015), the access to electricity annual growth rate in Burkina Faso from 2010 to 2012 is 0%. The rural electrification strategy for Burkina Faso is scattered in several electricity sector development policies: there is a need of defining a concrete action plan. Planning and coordination between grid extension and the off-grid electrification programme is essential to reach a long-term sustainable energy model and prevent high avoidable infrastructure investments. This paper goes into details on the methodology and findings of the developed Geographic Information Systems tool. The aim of the dynamic planning tool is to provide support to the national government and development partners to define an alternative electrification plan. Burkina Faso proves to be paradigm case for the methodology as its national policy for electrification is still dominated by grid extension and the government subsidising fossil fuel electricity production. However, the results of our analysis suggest that the current grid extension is becoming inefficient and unsustainable in order to reach the national energy access targets. The results also suggest that Burkina Faso's rural electrification strategy should be driven local renewable resources to power distributed mini-grids. We find that this approach would connect more people to power more quickly, and would reduce fossil fuel use that would otherwise be necessary for grid extension options.
Full-text available
Electricity production in Mediterranean islands currently depends heavily on imported fossil fuels. This strategy has several disadvantages and has been accused of hindering the islands' sustainable development. In the present research an integrated approach to increase solar photovoltaic (PV) systems' (SPVS) share in the energy mix of Mediterranean islands is presented, through installations on the available surface near existing water infrastructure. Accordingly, we have analyzed the potential of existing dams to accommodate SPVS on their downstream face as well as the option of SPVS over irrigation canals. We processed databases of water infrastructure in five big islands and developed a methodology to identify favorable locations. Using geographic information system (GIS) we processed the technical characteristics of each location and calculated the potential power capacity and the corresponding electricity production. Eleven dams were identified as ''first-rate " locations with a total generating capacity of 63 MWp, producing 97 GW h of electricity annually, while additional 10 dams with less optimal conditions would add 30 MW of capacity and 33 GW h of annual production. We also identified an additional advantage of placing SPVS over irrigation canals, proposing additional 60 MWp capacity, namely the significant water savings through reduced evaporation.
Full-text available
The design goals of the developed software are described followed by its architecture, which is presented in detail. The GUI-based interface supports a variety of environmental management problems and can provide best practices in a timely manner. The toolkit is generic and applicable to any scientific field. It was applied on a renewable energy (RE) system’s management. The developed model simulates the hydraulic characteristics of a small-scale hydropower (SHP) station. Harmony search algorithm (HSA) toolkit optimized the SHP’s operation, without violating the ecological constraints related to environmental flow (EF) regimes. This was equal to maximizing the revenues from SHP’s energy production in terms of a hypothetical fluctuating market. Apart from securing the provision of EF regimes, HSA toolkit’s outcome provided management practices that increased the total economic gains. Supporting the economic viability of SHPs and their environmental friendliness is needed to strengthen their role in the RE mix.
The clean energy transition requires a co-evolution of innovation, investment, and deployment strategies for emerging energy storage technologies. A deeply decarbonized energy system research platform needs materials science advances in battery technology to overcome the intermittency challenges of wind and solar electricity. Simultaneously, policies designed to build market growth and innovation in battery storage may complement cost reductions across a suite of clean energy technologies. Further integration of R&D and deployment of new storage technologies paves a clear route toward cost-effective low-carbon electricity. Here we analyse deployment and innovation using a two-factor model that integrates the value of investment in materials innovation and technology deployment over time from an empirical dataset covering battery storage technology. Complementary advances in battery storage are of utmost importance to decarbonization alongside improvements in renewable electricity sources. We find and chart a viable path to dispatchable US$1 W−1 solar with US$100 kWh−1 battery storage that enables combinations of solar, wind, and storage to compete directly with fossil-based electricity options.
For the next decade, the global water crisis remains the risk of highest concern, and ranks ahead of climate change, extreme weather events, food crises and social instability. Across the globe, nearly one in ten people is without access to an improved drinking water source. Least Developed Countries (LDCs) especially in sub-Saharan Africa (SSA) are the most affected, having disproportionately more of the global population without access to clean water than other major regions. Population growth, changing lifestyles, increasing pollution and accelerating urbanization will continue to widen the gap between the demand for water and available supply especially in urban areas, and disproportionately affect informal settlements, where the majority of SSA's urban population resides. Distribution and allocation of water will be affected by climate-induced water stresses, poor institutions, ineffective governance, and weak political will to address scarcity and mediate uncertainties in future supply. While attempts have been made by many scientists to examine different dimensions of water scarcity and urban population dynamics, there are few comprehensive reviews, especially focused on the particular situation in Sub-Saharan Africa. This paper contributes to interdisciplinary understanding of urban water supply by distilling and integrating relevant empirical knowledge on urban dynamics and water issues in SSA, focusing on progress made and associated challenges. It then points out future research directions including the need to understand how alternatives to centralized water policies may help deliver sustainable water supply to cities and informal settlements in the region.
Stéphanie Roblin explores the use of solar power in farming and explains why it could be an ideal solution to irrigation in developing countries.
Despite the impressive gains in global food production over the last half century, an estimated 790 million people remain hungry. Many of the chronically hungry are poor farm families, who have neither the means to produce the food they need nor sufficient income to purchase it. For them, access to irrigation writer, or the means to use the water they have more productively, is a key to increasing their crop production, their incomes, and their household food security. Ironically, a technology typically associated with wealthy farmers, drip irrigation, may hold the key to alleviating a significant share of rural hunger and poverty. A new spectrum of drip systems keyed to different income levels and farm sizes (beginning with a US$5 bucket kit for home gardens) now exists and can form the backbone of a second green revolution, this one aimed specifically at poor farmers in sub-Saharan Africa, Asia, and Latin America. We describe the experience with affordable drip irrigation to date, including its growing use in India and Nepal, as well as the wide range of geographic areas and conditions where these systems may be useful. We propose a major new international initiative to spread low-cost drip irrigation through private microenterprise, with the aim of reducing the hunger and increasing the incomes of 150 million of the world's poorest rural people over the next 15 years. Our estimates suggest that such an initiative could boost annual net income among the rural poor by some US$3 billion per year and inject two or three times this amount into the poorest parts of the developing world's economies.