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A financial and technical assessment of solar versus hand water pumping for off-grid area -the case of Burkina Faso

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Hand and solar water pumping systems are considered as improved water supplies for rural areas of African countries with no access to piped water. Hand pumps are widely used because of their low initial capital costs but they are limited in terms of maximum flow rate of water. Furthermore, they are said to be more tiring to use than solar pumps. Solar pumps are a technology that is developing and is less time and energy consuming but their high initial capital costs remain a barrier to their further deployment. This study aims at developing a methodology to compare in terms of costs, photovoltaic (PV) water pumping systems to hand pumping systems, supplying water for domestic use. They are located in a rural region with no access to a water distribution scheme. A technical analysis has been done to define the systems, followed by an economic analysis to calculate the life cycle cost of both systems as well as the cost of water. Questionnaires have been submitted to collect cost data. In a sensitivity analysis, the lifespan of the systems and flow rates are modified and adjusted to find their influence on the cost of water for both systems. This methodology was applied to the case of Burkina Faso. It appears that, for the base case in Burkina Faso, the life cycle cost and the cost of water of a hand pump are lower than the one of a solar pump. Interviews performed have shown that the main decision factor between solar or hand pumps was the cost, even if the two types of pumps do not provide the users with the same level of service. However, the sensitivity analysis shows that the cost of water becomes smaller for solar pumps in some cases. Indeed, their initial capital cost is balanced by a higher flow rate or longer lifespan which means a higher output of water. Thus, for communities with a small requirement in terms of water quantity, a solar pump represents a heavy investment. But for high water requirements, if the maximum flow rate of the hand pump is 13 m 3 /day or 5 m 3 /day, then it is respectively from 30 m 3 /day and 12 m 3 /day requirement that the cost of water becomes smaller for solar pumps. When it is necessary to install several hand pumps whereas only one solar pump could be enough, this study has demonstrated that the cost of water from a solar pump could be inferior to the one of a hand pump. 3
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1
A financial and technical assessment of solar versus hand
water pumping for off-grid area the case of Burkina Faso
Elvire André de La Fresnaye
31st August 2018
Supervised by Dr. Judith Cherni
Co-Supervisors: Dr. Loïc Quéval and Simon Meunier
A thesis presented to Imperial College London in partial fulfilment of the
requirements for the degree of Master of Science in Sustainable Energy Futures
and for the Diploma of Imperial College 
Energy Futures Lab
Imperial College London
SW7 2AZ
2
Abstract
Hand and solar water pumping systems are considered as improved water supplies for rural areas of
African countries with no access to piped water. Hand pumps are widely used because of their low initial
capital costs but they are limited in terms of maximum flow rate of water. Furthermore, they are said to
be more tiring to use than solar pumps. Solar pumps are a technology that is developing and is less time
and energy consuming but their high initial capital costs remain a barrier to their further deployment.
This study aims at developing a methodology to compare in terms of costs, photovoltaic (PV) water
pumping systems to hand pumping systems, supplying water for domestic use. They are located in a
rural region with no access to a water distribution scheme. A technical analysis has been done to define
the systems, followed by an economic analysis to calculate the life cycle cost of both systems as well as
the cost of water. Questionnaires have been submitted to collect cost data. In a sensitivity analysis, the
lifespan of the systems and flow rates are modified and adjusted to find their influence on the cost of
water for both systems. This methodology was applied to the case of Burkina Faso.
It appears that, for the base case in Burkina Faso, the life cycle cost and the cost of water of a hand pump
are lower than the one of a solar pump. Interviews performed have shown that the main decision factor
between solar or hand pumps was the cost, even if the two types of pumps do not provide the users with
the same level of service. However, the sensitivity analysis shows that the cost of water becomes smaller
for solar pumps in some cases. Indeed, their initial capital cost is balanced by a higher flow rate or longer
lifespan which means a higher output of water. Thus, for communities with a small requirement in terms
of water quantity, a solar pump represents a heavy investment. But for high water requirements, if the
maximum flow rate of the hand pump is 13 m3/day or 5 m3/day, then it is respectively from 30 m3/day
and 12 m3/day requirement that the cost of water becomes smaller for solar pumps. When it is necessary
to install several hand pumps whereas only one solar pump could be enough, this study has demonstrated
that the cost of water from a solar pump could be inferior to the one of a hand pump.
3
Acknowledgements
First of all, I would like to thank Dr. Judith Cherni for her constructive assistance and guidance with
valuable advice. I would like to express my sincerest gratitude towards Dr. Loïc Queval for his helpful
guidance during all my research. I would also particularly like to thank Simon Meunier for his
availability and very precious help. I am very grateful for his continuous support throughout all the
thesis.
I would also like to thank Arouna Darga for his precious help in the organisation of the field trip, Basile
Darga for all the useful contacts he gave me and for lending me his house in Garango during my stay
there, Patrick de Lalande who warmly welcomed us in Ouagadougou, but also Séverin, Achille and
Ghislain Darga who have accompanied us during all the field trip and made us discover the Burkinabe
culture and traditions.
Finally, I wish to thank Gavin Eves for his help throughout the year but also my family and friends for
their unfailing support and encouragements.
4
Table of content
Abstract ................................................................................................................................................... 2!
Acknowledgements ................................................................................................................................ 3!
Chapter 1! Introduction ..................................................................................................................... 9!
Chapter 2! Background: a literature review .................................................................................. 11!
2.1.!Access to water in off-grid areas of developing countries ............................................... 11!
2.1.1.!Importance of a clean water access ............................................................................. 11!
2.1.2.!The situation in Sub-Saharan countries ....................................................................... 13!
2.1.3.!Drinking water situation in Burkina Faso .................................................................... 13!
2.2.!Water sources and water extraction techniques for rural poor regions ....................... 15!
2.2.1.!Water sources for groundwater, surface water and pluvial water ............................... 15!
2.2.2.!Water extraction techniques ........................................................................................ 18!
2.2.3.!Combinations of water sources and water extraction techniques ................................ 21!
2.2.4.!Economic viability of the alternatives ......................................................................... 22!
2.2.5.!Environmental costs of water extraction techniques ................................................... 22!
2.2.6.!Choice to focus on hand pumps and solar pumps ........................................................ 23!
2.3.!Economic analysis of solar pumps and hand pumps ....................................................... 23!
2.3.1.!Life cycle cost analysis ................................................................................................ 23!
2.3.2.!Review of costs for solar pumps and hand pumps - by cost types .............................. 25!
2.3.3.!Review of costs for solar and hand pumps case studies in different countries ......... 28!
2.4.!Benefit analysis of solar pumps and hand pumps ........................................................... 30!
2.4.1.!Benefit analysis methodology ...................................................................................... 30!
2.4.2.!A comparative analysis of the benefits of hand pumps and solar pumps .................... 30!
2.5.!Conclusion ........................................................................................................................... 31!
Chapter 3! Research methodology and data collection ................................................................. 33!
3.1. !Introduction ........................................................................................................................ 33!
3.2.!Methods used ...................................................................................................................... 33!
3.2.1.!Technical analysis ........................................................................................................ 33!
3.2.2.!Economic analysis ....................................................................................................... 35!
3.2.3.!Sensitivity analysis ...................................................................................................... 36!
3.3.!Data collection ..................................................................................................................... 36!
3.3.1.!Case study details ........................................................................................................ 37!
3.3.2.!Primary data acquisition .............................................................................................. 37!
3.3.3.!Secondary data ............................................................................................................. 39!
5
3.4.!Conclusion ........................................................................................................................... 40!
Chapter 4! Solar and hand water pumps: a technical analysis .................................................... 41!
4.1.!Introduction ........................................................................................................................ 41!
4.2.!Architecture of the systems ................................................................................................ 41!
4.2.1.!Hand water pumps ....................................................................................................... 41!
4.2.2.!Solar water pumps ....................................................................................................... 42!
4.2.!Boundary conditions .......................................................................................................... 43!
4.3.!Sizing of the solar pump .................................................................................................... 43!
4.3.1.!Price of transporting the drilling material .................................................................... 43!
4.3.2.!Power necessary from solar panels as a function of the hydraulic energy .................. 44!
4.3.3.!Price of the solar panel as a function of the installed PV power ................................. 45!
4.3.4.!Price of PV modules support structure as a function of the power installed ............... 45!
4.3.5.!Price of the pump as a function of the PV power installed ......................................... 46!
4.3.6.!Size of the tank ............................................................................................................ 47!
4.3.7.!Price of the tank as a function of its size ..................................................................... 47!
4.4.!Lifespan of pumping projects considered in the analysis ............................................... 47!
4.5.!Conclusion ........................................................................................................................... 48!
Chapter 5! Life cycle cost for solar and hand pumping systems .................................................. 49!
5.1.!Introduction ........................................................................................................................ 49!
5.2.!Initial capital costs .............................................................................................................. 49!
5.2.1.!Estimating the initial capital costs for hand pumps ..................................................... 49!
5.2.2.!Estimating the initial capital costs for PVWPS ........................................................... 50!
5.2.3.!Results .......................................................................................................................... 54!
5.3.!Maintenance costs for both pumping systems ................................................................. 57!
5.3.1.!Estimating maintenance costs for hand pumps ............................................................ 57!
5.3.2.!Estimating maintenance costs for PVWPS .................................................................. 60!
5.3.3.!Results .......................................................................................................................... 61!
5.4.!Discount rate ....................................................................................................................... 62!
5.5.!Results: computation of economic indicators .................................................................. 62!
5.5.1.!Life cycle cost .............................................................................................................. 63!
5.5.2.!Levelized cost of water ................................................................................................ 63!
5.6.!Summary and conclusion ................................................................................................... 63!
Chapter 6! Impacts of the variation of several parameters on the levelized cost of water: a
sensitivity analysis ................................................................................................................................ 65!
6.1.!Choice of the parameters ................................................................................................... 65!
6
6.1.1.!Lifespan of the system ................................................................................................. 65!
6.1.2.!Utilization factor and flow rate of water ...................................................................... 65!
6.1.3.!Discount rate ................................................................................................................ 66!
6.2.!Influence on the levelized cost of water: single variation of parameters ....................... 66!
6.2.1.!Influence of the lifespan on the levelized cost of water .............................................. 66!
6.2.2.!Influence of the flow rate of water on the cost of water .............................................. 67!
6.1.3.!Influence of the discount rate on the cost of water ...................................................... 69!
6.3.!Influence on the levelized cost of water: dual variation of parameters ......................... 70!
6.4.!Conclusion ........................................................................................................................... 71!
Chapter 7! Stakeholders’ views and discussion ............................................................................. 72!
7.1.!Stakeholders’ views ............................................................................................................ 72!
7.2.!Discussion of the results ..................................................................................................... 73!
Chapter 8! Conclusion ...................................................................................................................... 75!
Appendix ............................................................................................................................................... 77!
Bibliography ......................................................................................................................................... 92!
7
List of tables
Table 1: Benefits of investing in water and sanitation (author’s table) ................................................. 12!
Table 2: Water sources associated with the origin of water (author’s table) ......................................... 16!
Table 3: Advantages and drawbacks of some water sources (author’s table) ....................................... 18!
Table 4: Advantages and drawbacks of each water extraction technique (author’s table) .................... 20!
Table 5: Different combinations of water origin, water sources and techniques to extract water (author’s
table) ...................................................................................................................................................... 21!
Table 6: Example of recurrent O&M costs for an India Mark II hand pump (Harvey and Reed, 2014)
................................................................................................................................................................ 27!
Table 7: Lifespan of solar pumps and hand pumps (author’s table) ...................................................... 28!
Table 8: Quote requests to different suppliers of solar pumps (author’s table) ..................................... 38!
Table 9: Details of the interviews conducted in Burkina Faso (author’s table) ..................................... 39!
Table 10: Main elements of the architecture of a solar pump (author’s table) ...................................... 42!
Table 11: Lifespan of solar pumps and hand pumps (author’s table) .................................................... 48!
Table 12: Average costs of the components of a hand pump (author’s table) ....................................... 54!
Table 13: Cost and frequency of replacement of the main components of a hand pump (author’s table)
................................................................................................................................................................ 59!
Table 14: Expected lifespan for different components of a solar pump (author’s table) ...................... 61!
Table 15: Summary of the findings from chapter 5 (author’s table) ..................................................... 64!
Table 16: Identified gaps in the literature (author’s table) .................................................................... 74!
List of figures
Figure 1: Access to drinking water in Burkina Faso .............................................................................. 14!
Figure 2: Access to improved rural Water and Sanitation and trend required to meet the Sustainable
Development Goals in Burkina Faso ..................................................................................................... 14!
Figure 3: Cost breakdown structure for a pumping project (Hoang, 2017) ........................................... 34!
Figure 4: Main components of an INDIA hand pumps (Kapoeta North County Rural Water Service
Board, 2014) .......................................................................................................................................... 41!
Figure 5: Schematic of a solar pump (Meunier et al., 2018) ................................................................. 43!
Figure 6: Price of a PV module as a function of the power ................................................................... 45!
Figure 7: Price of the structure PV modules as a function of the power of the module ........................ 46!
Figure 8: Price of a motor pump as a function of the nominal power of the PV panels ........................ 46!
Figure 9: Price of a polytank as a function of its capacity ..................................................................... 47!
Figure 10: Initial cost items for a hand pump ........................................................................................ 55!
Figure 11: Capital costs of a PVWPS as a function of the daily flow rate of water .............................. 56!
Figure 12: Initial cost items for a solar pump ........................................................................................ 56!
Figure 13: Breakdown of the costs for solar and hand pumps ............................................................... 63!
Figure 14: LCOW as a function of the lifespan of the system for solar pumps and hand pumps ......... 67!
Figure 15: The cost of water as a function of the flow rate - maximum hand pump flow rate of 13
m3/day .................................................................................................................................................... 68!
Figure 16: LCOW as a function of the flow rate - maximum hand pump flow rate of 5 m3/day ......... 69!
Figure 17: LCOW as a function of the discount rate ............................................................................. 70!
Figure 18: Influence of the flow rate and the lifespan of the LCOW for solar and hand pumps .......... 71!
8
List of abbreviations and symbols
Abbreviations
!
"
Volume of the reservoir
AC
Alternative Current
#$"
Price of the reservoir
DC
Direct Current
#$
%&'%
Price of the pump
IC
Investment cost
#$()
Price of the PV panels
LCC
Life cycle cost
#$*()*+"
Price if the support structure for
the PV panels
LCOW
Levelized cost of water
#$,-,.*
Price of the electrical
connections
PV
Photovoltaic
#$-+
Price of the level sensor and
connections
PVWPS
Photovoltaic Water Pumping
System
#$./0"
Price of the controller
TDH
Total dynamic head
#$"*+"
Price of the metal structure and
concrete foundation for the tank
Wp
Watt peak
#$,1&2%
Price of supplying and
withdrawing the drilling material
Symbols
#$342--
Cost of drilling the borehole
Q
Flow rate
#$524-26"
Price of the airlift development
technology
N
Number of days of storage
#$*",+"+
Price of the pumping tests
#()
Power of the solar panels
#$505-7+2+
Price of water analysis
89
Energy from the pump needed
to pump the water
#$%2%,+
Price of the piping system
g
Acceleration of gravity
#$+"%2%,
Price of the standpipe
:
Density
#$+"&32,+
Price of the geophysical studies
Units
All the prices are expressed in euros and the rates retained are:
1 = 656 FCFA (rate on the 23/08/2018)
1 US $ = 0.86 (rate on the 23/08/2018)
1 = 7 TL (rate on the 23/08/2018)
9
Chapter 1 Introduction
As many as 884 million people lack access to safe water supplies worldwide and 2.6 billion people are
without access to basic sanitation (OECD, 2011). Moreover, 10% of the diseases - 30% in developing
countries - could be prevented with improvements in water, sanitation and hygiene as well as a better
management of the water resource (OECD, 2011). Several ways to supply water exist and among them,
hand pumps are currently the most used in rural areas of African countries. PV water pumping systems
are seen as a promising solution but the main barrier today to their further deployment remains their
high initial capital cost. However, the maintenance costs are often underestimated in the case of hand
pumps which are made up of more moving parts than solar pumps. Moreover, the cost of solar panels
has been decreasing over the past few years and the technology is becoming more accessible to
developing countries.
Researchers and governments have been doing studies about the different ways to collect water in off-
grid areas of developing countries, comparing wind, diesel and solar water pumping systems. The
consensus in the literature is that, among motorised pumping systems, PV water pumping systems are
the most promising technology for a deployment in developing countries. However, to our knowledge,
no study regarding the economic comparison between solar pumps and hand pumps was performed and
very few precise studies exist on how much are the initial investment costs for hand pumps and solar
pumps.
This study aims at developing a methodology to compare economically photovoltaic (PV) water
pumping systems to hand pumping systems, supplying water for domestic use. This economic analysis
is then conducted in the context of a rural region of Burkina Faso with no access to a water distribution
scheme. A combined methods methodology has been applied to analyse the costs of both systems.
PVWPS used to supply a distribution scheme are not in the scope of the study. This study is focusing
on the cost for the user, not taking into account the cost for the supplier, assumed to be included in the
final price paid by the user.
This study goes further than previous works that have already been done. Most economic studies of PV
water pumping systems choose to focus on one system but here it has been chosen to analyse a range of
systems. The specificity of this study is to use on-the-field data to obtain the equations of the model and
have a more reliable and precise idea of the costs of such a system. This aims at finding the most precise
cost over its lifespan for a particular system in Burkina Faso. In the scope of this study, new information
has been gathered on the field. The diversity of prices is very large and this could help a potential
installer or NGO willing to install a new system to have a reference for a new system in Burkina Faso.
The results of this study will highlight the relative interest of investing in PV pumping instead of other
water extraction systems, and especially hand pumps which are currently the most used “improved water
supply” in sub-Saharan countries. This would therefore be valuable to governments, companies and
NGOs.
Chapter 2 Background: a literature review
This literature review aims at giving an overview of the current situation in terms of access to water in
remote areas of developing countries, as well as the technologies used to provide this access. A review
and comparison of many extraction technologies was done and the study was then narrowed down to
hand pumps and solar pumps. The last parts focus on a review of costs and comparative benefits of hand
pumps and solar pumps.
2.1. Access to water in off-grid areas of developing countries
2.1.1. Importance of a clean water access
a) Definition(of(improved(water(supply(and(reasonable(access(to(water((
An improved water supply includes piped water on premises, public stand-pipe, boreholes, dug wells,
protected springs, and rainwater collection (WHO/UNICEF, 2010). Unprotected wells and springs,
vendors and tanker trucks are considered as unimproved technologies (WHO/UNICEF, 2010).
A reasonable access to water in a rural area is the availability of at least 20 litres per day per person from
a source that is nearer than 1 km from the person’s house (Cairncross & Valdmanis, 2006; Agence
Française de développement, 2011).
b) Benefits(of(a(reasonable(access(to(water(in(developing(countries(
The benefits from having a reasonable access to water from an improved water supply can be separated
into three main categories are: health benefits, environmental benefits, economic benefits and other
benefits. Although health benefits from an improved access to water are the most obvious and direct
ones, economic benefits, such as increased productivity, reduction in healthcare costs or impact on
tourism, are also very important and show some incentives to invest in this field. Water access is a key
in the economic development of some sub-Saharan countries. These benefits can be achieved by
investments which are divided into 3 categories: investment to provide access to safe water and
sanitation, investment in wastewater treatment for safe disposal and reuse and investment in the
management of supply and demand balance sustainably (OECD, 2011). In Table 1, the different benefits
of investments in the water sector have been classified according to the three categories of investments
mentioned.
Health
benefits
Environmental
benefits
Economic
benefits
Other
benefits
References
Investment to provide
access to safe water
and sanitation which
includes
building water access
points, networks,
water treatment plant,
sanitation and hygiene
facilities
Reduced
diseases 1,4
More time saved
for productive
activities1,2,4
Reduced coping
costs1
Impact on
tourism from
improved
facilities1,3
Savings in
healthcare
costs2,3
Improvement
in cleanliness
and dignity1,3
Increased
school
attendance
for children1,2
Greater
equality
between men
and women 3
1 : OECD,
2011
2 : Hutton
and Haller,
2004
3 :
UNICEF,
2012
Investment in
wastewater treatment
for safe disposal and
reuse which includes
building and
operating wastewater
treatment plants as
well as relying on
natural treatment
processes
Health
benefits due
to improved
quality of
recreational
water1
Reduced
eutrophication1
Better quality
of surface
water1
Reduced pre-
treatment costs1
Protection of
commercial fish
stocks and
aquaculture1
Increased water
supply for
irrigation1
Less use of
fertilisers with
the use of sludge1
Higher property
values1
1 : OECD,
2011
Investment in the
management of
supply and demand
balance sustainably
which includes
protecting water
resources, increasing
and ensuring supply
by building storage
capacity for example,
and managing
demand
Reduced
pressure on
available
resources1
Economic
impacts on use
of water for
economic
activities such
as agriculture
and
hydropower1
Reduced costs1
Reliable supply
for production
processes1
Reduced costs to
adapt from
unreliable water
supplies1
Downsizing of
facilities1
Reduced need for
desalination1
Better quality
of life1,4
1 : OECD,
2011
4:
Arlosoroff
et al., 1988
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2.1.2. The situation in Sub-Saharan countries
Recent studies have shown that more than two third of sub-Saharan African population leave their home
to get some water (Graham, Mirai and Kim, 2016). An even more alarming fact is that, in Sub-Saharan
Africa, two people out of five lack drinking water (Ntouda et al, 2012).
The water Millenium Development goal was not met in 2012 with only 64% of the sub-Saharan Africa
population having a sustainable access to water and basic sanitation instead of the 77.5% goal (WHO
and UNICEF, 2014).
This observation has health consequences. An analysis of the relationships between access to clean water
and occurrence of diseases among the population of some sub-Saharan countries shows that in
Cameroon, for example, children living in a household with no access to drinking water are 1.29 times
more likely to get diarrheal diseases than those living in households with an easy access to water (Ntouda
et al, 2012). This study also underlines the disparities between rural and urban areas of sub-Saharan
countries: the risk of diarrheal diseases for children is higher in rural areas (Ntouda et al, 2012). Indeed,
children living in rural areas have 1.83 (Senegal), 1.11 (Chad) and 1.09 (Cameroon) times more
probability to get diarrhea than children living in urban areas (Ntouda et al, 2012). In Nigeria, it is
estimated that 119,700 deaths per year are due to water supply, and sanitation (Cloutier and Rowley,
2011).
2.1.3. Drinking water situation in Burkina Faso
Burkina Faso is a country of 19.6 million inhabitants, 71% of them are rural (CABRI, 2017). The total
population of the country is expected to rise up to 29 million by 2030 and 60% of them will still live in
rural areas (CABRI, 2017). The population is currently growing at a rate of 2.9% per year (World Bank,
2017). Burkina Faso is the 185th country out of the 188 countries ranked by the UN in terms of Human
Development Index (United Nations development programme, 2016). Almost half of the population
lives under the poverty line, with less than 1.60 per day (CABRI, 2017). This country has done lots of
efforts to to improve access to drinking water for the past 15 years (Pezon, Bassono, 2012). The National
Water Programme 20162030 (PN-AEP 2016-2030) was established by the Ministry of Water and
Sanitation. It suggests to phase out hand pumps and move towards piped services (CABRI, 2017). For
now, a third of the rural population does not even have access to a hand pump (CABRI, 2017).
In Burkina Faso, 97% of the households in rural areas do not have water on premises (Graham, Mirai
and Kim, 2016). Nevertheless, 82% of the population of Burkina Faso have access to an improved water
supply (World Bank, 2015). However, Figure 1 underlines the disparities between rural and urban
population in terms of access to water. Focusing on the rural population, 30% of them have access to an
unimproved water source only.
&
:,163%&'(&;<<%..&-/&43,*=,*1&2"-%3&,*&)63=,*"&:"./&
&
Figure 2 underlines the dynamics of access to improved rural water over the last decades. Overall,
between 1990 and 2010, the proportion of people with access to an improved water source went from
less than 40% to more than 70%. During the 1990s and at the beginning of the 20th century, the trend
was rapid, but a slowdown is noticed from around 2005 onwards. From this point the increase in access
only meets the growth of the population (CABRI, 2017).
&
&
In 90% of the cases, the primary water collector is an adult female and, in 5% of the cases, it is a child
(Graham, Mirai and Kim, 2016). For 34% of the households, more than 30 minutes round trip are
:,163%&>(&;<<%..&-/&,?@3/0%4&363"$& A"-%3&"*4&B"*,-"-, /*&"*4&-3%*4&3%C6, 3%4&- /&?%%-&-7%&B6. -",*" #$%&
D%0%$/@?%*-&E/"$.&,*&)63=,*"&:"./&
necessary to collect water (Graham, Mirai and Kim, 2016). In this case, 88% of the primary collectors
in the households surveyed were an adult female and 6% were a child (Graham, Mirai and Kim, 2016).
The gender ratio (female/male) for the primary collectors of water when they are spending more than
30 minutes to get it is 15.1 for adults and 1.6 for children (Graham, Mirai and Kim, 2016). This means
that, in Burkina Faso, but also in most of sub-Saharan countries, women are by far the primary collectors
of water (Graham, Mirai and Kim, 2016; Emenike et al., 2017; Phiri, Rowley and Blanchard, 2015).
This underlines the improvement in equality between men and women that could be achieved with a
better water supply.
Health consequences from an inadequate water supply in Burkina Faso are very important. Water,
sanitation and hygiene related diarrhoea is responsible for the deaths of more than 4000 Burkinabe
children per year (WHO, 2014).
Economic issues associated with water access are huge. But the economic benefits of investing in water
supply for Burkina Faso would be more than 2.4 times the cost of the investment, according to a cost-
benefit analysis (CABRI, 2017). Dignity, safety and security are other benefits that are hard to quantify.
2.2. Water sources and water extraction techniques for rural poor regions
In this section, different water sources and water extraction techniques will be defined and described.
Advantages and drawbacks of each of those will also be discussed. This will lead to a further discussion
about environmental impacts and economic analysis of the water extraction techniques. This part aims
at explaining the choice to focus on solar pumps and hand pumps, in sections 4 and 5 of this literature
review, rather than on other systems.
A drinking-water source can be "any fresh water produced by the hydrological cycle" (Carlevaro and
Gonzalez, 2015). Water origins can be categorized in three main types: groundwater, surface water and
pluvial water (Carlevaro and Gonzalez, 2015). A water extraction system is a technology enabling the
collection of water.
2.2.1. Water sources for groundwater, surface water and pluvial water
Groundwater has proved to be the most reliable resource for meeting rural water demand in sub-
Saharan countries (MacDonald & Davies, 2000) because it is available beneath much of the continent,
is generally better quality than surface or pluvial sources, and can be relatively easy and cheap to access
and extract (Harvey and Reed, 2004). Because of its higher quality, it requires less treatment than surface
water and is easier to protect from contamination (Carlevaro and Gonzalez, 2015; Rubab and Kandpal,
1998; Phiri, Rowley and Blanchard, 2015). Groundwater sources include upland springs, artesian
springs and wells, deep and shallow wells, and infiltration galleries (Carlevaro and Gonzalez, 2015).
Surface water sources include small upland streams, lakes, ponds and rivers (Carlevaro and Gonzalez,
2015). Considering surface water as a source of drinking water must only be a second option after
groundwater sources (Carlevaro and Gonzalez, 2015). Indeed, the quality of surface water is very
variable and depends on the content of living organisms, mineral and organic matter inside it (Carlevaro
and Gonzalez, 2015). But they require treatment nearly all the time (Carlevaro and Gonzalez, 2015).
Pluvial water can be collected by catchment systems: from the roof by gutters and down-pipes; and can
then be stored (Carlevaro and Gonzalez, 2015).
Table 2 summarizes the different water sources and the origin they come from, whether it be
groundwater, surface or pluvial water. The three main sources are wells, intakes and catchment systems
(Carlevaro and Gonzalez, 2015) which can be divided in sub-categories mentioned in the table.
Water origin
category
Water origin
Water source
Ground water
Aquifer (shallow)
Hand-dug well
Aquifer (deep)
Borehole, drilled well or tube well
Aquifer
Subsurface harvesting system
Water flows at the surface
from springs
Spring water collection system
Surface Water
River, lake
Protected side-intake
Floating intake
Sump intake
Small river, stream
River-bottom intake
Rainwater
Rain
Rooftop harvesting
Catchment areas and storage dam
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It is relevant to focus on wells which will be the main object of the study. A well is a way to give access
to groundwater and facilitate its extraction (Carlevaro and Gonzalez, 2015). Wells can be divided in five
sub categories which depend on the way they are constructed (Carlevaro and Gonzalez, 2015).
Hand-dug wells that are a cheap and common way to extract water which can be collected with a bucket
and a rope (Carlevaro and Gonzalez, 2015) or with a hand pump. Driven wells are dug with a pointed
metal instrument that is driven into the ground with a hammer (Carlevaro and Gonzalez, 2015). Jetted
wells are dug with the help of a powerful stream of water. But this require an important supply of water
and is often inadequate in developing countries lacking water access (Carlevaro and Gonzalez, 2015).
Bored wells are sunk by hands and a tool twisted into the ground (Carlevaro and Gonzalez, 2015).
Driven wells and bored wells can be gathered under the broader term tube wells. Lastly, drilled wells
refers to wells dug with engine powered equipments (Carlevaro and Gonzalez, 2015). They are
boreholes.
A hand-dug well must be large enough to allow a person to go into it to maintain it, it is most of the time
larger than 0.8m of diameter (Carlevaro and Gonzalez, 2015). Protection of such a well is recommended
to avoid contamination (Carlevaro and Gonzalez, 2015). Most of the time, this type of wells requires
only a small maintenance: daily checks to remove the potential debris in the well and in case of drying
of the well, it has to be deepened (Carlevaro and Gonzalez, 2015). The fence and drainage system should
also be regularly checked (Carlevaro and Gonzalez, 2015). The advantages of such a well are low
material costs and it can be dug easily with locally available materials (Carlevaro and Gonzalez, 2015).
When people are collecting water with a bucket and a rope, the type of wells used is dug wells.
Boreholes and tube wells are much narrower, usually their diameter is 0.1 - 0.25m (Carlevaro and
Gonzalez, 2015). These wells extract water with the use of a suction pump. The pumps used can either
be hand pumps or motorized pumps (Carlevaro and Gonzalez, 2015). The lifetime of such wells can be
of more than 20 years (Carlevaro and Gonzalez, 2015).
Determining whether a hand-dug well, tube well or machine-drilled borehole is the most appropriate
water source is key to the installation of a water extraction system (Harvey and Reed, 2004). The option
selected should be decided upon following an objective assessment. Hydrogeological factors have a
major impact on the different possibilities, but a number of other issues should be considered, such as
the cost, the rapidity and ease of construction for example (Harvey and Reed, 2004). When extracting
water from the ground, it is important to assess if open hand-dug wells, tube wells or boreholes are the
most appropriate (Harvey and Reed, 2004). Advantages and drawbacks of each type of wells are
summarized in Table 3.
Advantages
Drawbacks
References
Open hand-dug
wells
- Low initial costs1
- Can be constructed with
locally available tools,
material and skills1,2
- Can be constructed in
geological formation where
hand drilling is difficult1
- Water can still be accessed
if the pump breaks down
(with a bucket and a rope for
example)1
- Risk of
contamination/pollution if
not fully protected1,2
- Limited depth and limited
yield (hard to dig below
water table) 1,2
- Some safety risks for the
diggers and the users1
- Digging is time-consuming1
- Construction has to be done
at the time of the year when
the level of water is low2
1 : (Harvey and
Reed, 2004);
2: (Sonou,
1997)
Tube wells
(driven wells
and bored
wells)
- Low cost (cheaper than
hand-dug wells)1,2
- Relatively fast to dig1,2
- No security risks for the
users1
- Limited depth1
- Difficult to find suitable
environmental conditions1
- Water cannot be accessed if
the pumping system breaks
down1
- Fewer people of the
community involved in the
construction than for hand-
dug wells1
1 : (Harvey
and Reed,
2004);
1: (Sonou,
1997)
Machine-drilled
boreholes
- Low recurrent material
costs1
- Very fast construction1
- Can be used for irrigation
because of a higher yield1
- No security risks for the
users1
- Available for all types of
grounds and at great depths1
- Occasional major
maintenance may require a
high investment1
- High cost1
- Water cannot be accessed if
the pumping system breaks
down1
- Fewer people of the
community involved in the
construction than for hand-
dug wells1
1 : (Harvey
and Reed,
2004);
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2.2.2. Water extraction techniques
The context of this study is rural areas of developing countries, where no electricity from the grid is
available. Thus electric power from the grid to pump water is not considered.
Two main ways of extracting water have been identified in rural areas:
Extracting water manually:
o Gathering water with a bucket and a rope.
o Pumping water with a hand pump: Many different hand pumps exist but the majority of
them are positive displacement pumps (WaterAid, 2013). Low lift pumps can lift water up
to 15 meters, intermediate lift pumps can go down to 25 meters and high lift pumps can
reach more than 45 meters deep (WaterAid, 2013). This means that the large range of
different hand pumps can suit a large range of well depths. In comparison to the extraction
of water with a bucket and a rope, the water can be sealed to prevent its contamination
(WaterAid, 2013). Its life expectancy is usually around 10 years which is less than the one
of a solar pump (WaterAid, 2013). This is due to moving parts of hand pumps that break
down more easily and more regularly (WaterAid, 2013, Phiri, Rowley and Blanchard,
2015). More than 30 000 hand pumps exist in Burkina Faso and their failure rate is 23%
(16% are broken and 7% are abandoned) (Antea, 2006).
Extracting water with a motorised pump:
o Diesel pump: Diesel pumps can operate in remote areas where electricity from the grid is
not available, which makes them particularly suitable for stand-alone systems in rural areas
(Smet and van Wijk, 2002). However, diesel pumps rely on the provision of fuel (Smet and
van Wijk, 2002) and must be operated by a trained operator (Carlevaro and Gonzalez, 2015).
o Solar pump: Solar pumping systems are powered by photovoltaic panels (Smet and van
Wijk, 2002). The electricity powers the electric motor of a pump and can be stored in
batteries (Carlevaro and Gonzalez, 2015). The water can be pumped into a storage tank
(Smet and van Wijk, 2002). The only requirement for the use of solar pumps being a
sufficient irradiance, solar pumping systems are interesting economically if daily solar
energy is greater than 3 kW/m2 (Smet and van Wijk, 2002; Carlevaro and Gonzalez, 2015).
The most appropriate situation to use solar pumps is to fulfil the need for low power
requirement (less than 5 kW) in off-grid areas because it is when they are the most cost
effective (Omer, 2001). The main applications are domestic and livestock drinking water
supply (Omer, 2001).
In developing countries, most people are collecting water using a bucket and a rope or using a hand
pump (WaterAid, 2013; Hofkes and Visscher, 1986). Other extraction techniques are available but not
considered because not commonly used. For instance, neither wind pumping systems nor ram pumps
are considered in this study. Wind is less predictable, high maintenance is needed (Ratterman, Cohen
and Garwood, 2003) and it is 6 times more expensive than PV system in terms of initial investments
(Bossyns, 2013). For ram pump, the need of an appropriate site falling water at a lower level to be
moved to higher elevation (Ratterman, Cohen and Garwood, 2003) makes it less suitable.
Table 4 summarizes the advantages and drawbacks of the most frequent water extraction techniques in
developing countries. The advantages and drawbacks have been summarized into different categories:
technological, social, economic, health, efficiency and environmental.
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Water
extraction
technique
Advantages
Drawbacks
References
Manual
Bucket
and a rope
- Technological: Easy
operation and maintenance2
- Economic: Low repair
costs7, No fuel needed,
Easy installation
- Health: the bucket is easily
polluted with dirty hands and mud2
,7, physical effort to lift the bucket
- Technological: Risk of the bucket
falling into the well7
2 : (WaterAid, 2013)
7: (Carlevaro and
Gonzalez, 2015)
Hand
Pump
- Economic: Low cost1,3, 5
- Technological: Simple
technology1, Easy
maintenance1,3, 5, No fuel
needed1, Easy
installation1,3, Higher
volume of discharged water
than bucket + rope2
- Health: Water can be
sealed to prevent
contamination2
- Technological: Regular
maintenance needed1,2, Moving
parts can easily be broken2
- Efficiency: Low flow rates1,3
- Social: Time and energy
consuming1
2 : (WaterAid,
2013)
1 : (Ratterman,
Cohen and
Garwood, 2003)
3 : (Agence
Française de
Développement,
2011
5: (Smet & Wijk-
Sijbesma , 2002)
Motorised
Solar
pumping
system
- Technological: Easy
installation1, Long life
expectancy1, Low
maintenance, Simple
repair1,5, Clean1, No fuel
needed1,5
- Efficiency: Modular
system that can match the
needs1
- Efficiency: Seasonal variation of
solar energy1
- Economic: Highest initial
costs1,5,6
- Environmental: Can cause
shallow wells to dry5
1 : (Ratterman,
Cohen and
Garwood, 2003)
5: (Smet & Wijk-
Sijbesma , 2002)
6 : (Carlevaro and
Gonzalez, 2015)
Diesel
generator
- Economic: Moderate
initial cost1,6
- Technological: Easy
installation1
- Technological: Frequent
maintenance, expertise required1,6,
Short life1, Expensive fuel and
intermittent supply1,4, Noise, dirt,
fumes1
- Economic: Overall costs are
higher than SPS1
- Environmental: Can cause
shallow wells to dry5
1 : (Ratterman,
Cohen and
Garwood, 2003)
4 : (Smet and van
Wijk, 2002)
5: (Smet & Wijk-
Sijbesma , 2002)
6 : (Carlevaro and
Gonzalez, 2015)
2.2.3. Combinations of water sources and water extraction techniques
The combinations were taken from (Carlevaro and Gonzalez, 2015) and summarized in Table 5. The
options investigated in this study are written in red.
Water origin
category
Water origin
Water source
Water collection
technology
Ground water
Aquifer (shallow)
Hand-dug well
Bucket and rope or
hand pump
Aquifer (deep)
Borehole, drilled well
or tube well
Hand pump or solar
pump or diesel pump
Aquifer
Subsurface harvesting
system
Hand pump or solar
pump or diesel pump
Water flows at the
surface from springs
Spring water
collection system
N/A
Surface Water
River, lake
Protected side-intake
Hand pump or solar
pump or diesel pump
River, lake
Floating intake
Hand pump or solar
pump or diesel pump
Small river, stream
River-bottom intake
Hand pump or solar
pump or diesel pump
River, lake
Sump intake
Hand pump or solar
pump or diesel pump
Rainwater
Rainwater
Rooftop harvesting
N/A
Rainwater
Catchment areas and
storage dam
N/A
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Hand pumps are a suitable technology to be installed on deep wells and most hand pumps pump water
from drilled boreholes. But hand-augered boreholes also are possible solutions. In general, if it is
possible to dig, it must be considered before drilling because the cost is much lower (Harvey and Reed,
2004). But, in some cases, hand pumps may not be adapted to deep wells because the water table is too
low due to the absence of rain. During the choice of a water pumping system for a deep well, annual
precipitation is an important factor to consider. Indeed, the wetter the area, the less deep the groundwater
table is (Bonsor & MacDonald, 2011). If the average annual precipitation is low, more power is needed
to pump the water which is located deeper under the surface, and hand pumps are becoming
inappropriate solutions to pump the needed water (Bossyns, 2013).
Another important factor to take into consideration is that the extensive use of electric pumps (solar
powered for example) and diesel pumps can cause shallow wells to dry. This major impact on the
resource has to be closely monitored (Smet & Wijk-Sijbesma, 2002).
2.2.4. Economic viability of the alternatives
Several techno-economic analyses have been carried out to assess the feasibility of renewable energy
sources and technologies to substitute for diesel pumping systems and hand pumps.
In Nigeria, a study highlighted that if water demand at a particular site cannot be met by a hand pump,
a renewable energy-powered pumping system is an attractive option. Over the life of the asset, the fuel
costs of a petrol or diesel pumping system outweigh the high capital costs of renewable alternatives
(Cloutier and Rowley, 2011).
In the context of a rural and remote village in Nepal, after a life cycle cost analysis, a study concluded
that solar PV pumping system was the most economically viable compared to a diesel pumping system
despite higher initial costs (Parajuli, Pokharel and Østergaard, 2014).
In rural Mozambique, a theoretical study demonstrated that hand pumps were the most cost-effective
solution for shallow boreholes but their low flow rate implied the construction of several boreholes
which is capital intensive and favours solar pumps which are more efficient (Bossyns, 2013). It
concluded that solar powered pumping system was the most appropriate water supply technique
compared to hand pumps, diesel pumps or wind pumps (Bossyns, 2013).
However, the comparison of the economic viability of diesel and solar water pumps showed that a
mismatch between water demand and supply could have a negative impact on the economic viability of
the PV system (Odeh, Yohanis & Norton, 2006).
2.2.5. Environmental costs of water extraction techniques
Environmental costs of gathering water manually (from an open well with a bucket or using a hand
pump) are not investigated here because considered negligible compared to motorised pumping systems
(solar pumping system or diesel generator).
Life cycle analyses have been carried out to determine the amount of carbon dioxide released in the
environment during the life of a water extraction techniques. For a 3.4 kWp PV system located in Inner
Mongolia, China, 20 tons of CO2 are the total emissions over a life span of 20 years (Yang et al., 2014).
43.5% of the emissions are is due to PV panels out of which 89% comes from the construction phase of
the panels (Yang et al., 2014). Another study finds out that the use of 1000 solar pumps (power input of
950W and working 5h a day) can avoid the annual emission of 4.2 tons of CO2 compared to a diesel
pump (Ould-Amrouche, Rekioua, & Hamidat, 2010). With these data, it can be estimated that, over a
20-year life span, 84 tons of CO2 emissions could be saved with the use of one solar pumping system
instead of a diesel pumping system.
2.2.6. Choice to focus on hand pumps and solar pumps
Four combinations of water source and water extraction techniques were investigated in this section:
1. Gathering water from an open well with a bucket and a rope.
2. Pumping water from a borehole with a hand pump.
3. Pumping water from a borehole with a solar pump.
4. Pumping water from a borehole with a diesel pump.
Only the 2nd, 3rd and 4th methods are considered as improved water supply according to the definition in
the section 2.1.1., stagnating sources and open wells are unimproved water supply. The 1st method will
therefore not be considered by governments or NGOs as suitable solutions to access water in rural
villages of developing countries.
Among the motorised pumps, the effectiveness of diesel pump and solar pumping systems are
comparable (Bossyns, 2013) but it had been seen previously in section 3.4 and 3.5, that, from an
economic and environmental point of view, solar pumping systems were more appropriate in remote
areas of developing countries. Hand pumps are still widely used in sub-Saharan Africa (WaterAid, 2013)
and many are still being installed. This is why the following sections of the literature review will focus
on a comparison of solar pumps with hand pumps rather than diesel pumping systems.
2.3. Economic analysis of solar pumps and hand pumps
2.3.1. Life cycle cost analysis
A life cycle cost analysis is an estimation of the different costs over the whole life of an asset. It can be
useful to compare alternatives before making the choice to buy an asset (Woodward, 1997).
To conduct an appropriate life cycle cost analysis, the following elements have to be identified for the
asset: capital cost, operation cost, maintenance cost, decommissioning cost, lifespan, discount rate,
uncertainty and sensitivity analysis (Woodward, 1997).
(Meunier, 2017) proposed the following cost structure for the system:
Capital cost:
;<5%2"5- = * ;(&4.95+, > * ;?450+%/4"@./'%/0,0"+ > * ;A0+"5--5"2/0
KC6"-,/*&'&
;(&4.95+,: Cost of purchasing the components
;?450+%/4"@./'%/0,0"+: Cost of transporting the components of the system to the installation site
;A0+"5--5"2/0: Cost of installing the system
Operation cost:
;B%,45"2/0 = * ;C&,- > * ;D/4E6/4.,@/%,45"2/0
KC6"-,/*&>&
;C&,-: Cost of the fuel (for diesel pumps)
;D/4E6/4.,@/%,45"2/0: Cost of paying the employees, taking care and operating the system (for example
turning on the system, cleaning solar panels, greasing the motor, verifying the state of the system)
Maintenance cost:
;F520",050., = * ;F520",050.,@%&4.95+, > ;F520",050.,@G/4E6/4.,
KC6"-,/*&F&
;F520",050.,@%&4.95+, : Cost of purchasing the components for the maintenance
;F520",050.,@G/4E6/4., : Cost of workforce for the maintenance
Decommissioning cost:
HIJKLMNOONLPNPQ = * HINOMRPSTJMJPS > * HINOULORT
KC6"-,/*&G&
;V2+'50"-,',0": Cost of dismantling the system
;V2+%/+5-: Cost of disposing of the system
The lifespan of an asset has a major influence on the calculation of the life cycle cost. An expected
lifetime can be described in 5 different ways: the functional life at the end of which the asset is not
needed or used, the physical life at the end of which the asset is expected to dysfunction or break down,
the technological life at the end of which the asset can be replaced by more efficient assets, the economic
life at the end of which the technology is considered obsolete and not cost competitive anymore, the
social and legal life at the end of which users will want to change or laws will require it (Woodward,
1997). In the case of pumping systems, the physical life is the most appropriate description for the
lifespan, because pumping systems are usually used until they break down.
The discount rate reflects the rate at which people are willing to exchange present and future economic
benefits. It is a function of supply and demand for money and measures the loss of value of money after
a certain period of time. It is very important to choose a realistic discount rate because it will have an
influence on the economic analysis of the project.
The discount rate includes the interest rate W0 and inflation rate $. It is defined as (Riggs et al., 1996):
W = X > W0X > $ Y X**
KC6"-,/*&I&
To calculate life cycle cost, the net present value of all costs occurring during the life of the asset have
to be calculated. The net present value NPV of a cost occurring during the year t is given by:
Z#!* [ = * \"
]X > W^"
KC6"-,/*&L&
&
where Rt is the net cash flow at year t. The life cycle cost LCC is obtained with:
_;;* W` Z = * Z#!*][^
a
"bc
KC6"-,/*&M&
where N is the lifespan of the system and i is the discount rate. For solar PV, N it is estimated at 20
years (Parajuli, Pokharel and Østergaard, 2014; Phiri, Rowley and Blanchard, 2015). Life expectancy
of subsystems such as the motor or the pump are smaller and should be replaced during those 20 years
to match the life span of PV generators. These costs have to be considered in the life cycle cost
calculation (Ould-Amrouche, Rekioua, & Hamidat, 2010).
The levelized cost of water is the life cycle cost of the system divided by the total output of water over
the whole life of the asset (Cloutier & Rowley, 2011).
_;de = * _Wfghihjg*hkl[*kf*m*n$kogh[*kpg$*W[l*jWfglnmq*]gr$kl^
em[g$*ks[mWqgt*kpg$*W[l*jWfglnmq*]uv^
KC6"-,/*&N&
2.3.2. Review of costs for solar pumps and hand pumps - by cost types
a) Capital(costs(
PV modules represent one of the major cost items for a solar pumping project (Campana, 2013). But the
prices of the modules are highly dependent on the market and the time of purchase. For instance, for the
Chinese market in 2012, the cost of the modules was 0.5 /Wp and the structure for the modules cost
0.09 /Wp (Campana, 2013). For a unit of 310 W in 2015, it would cost 141 in Chile (Montorfano,
Sbarbaro & Mor, 2015), which corresponds to 0.38 /Wp. In Algeria in 2011, the PV modules cost
2.9 /W (Bakelli, Hadj Arab & Azoui, 2011). In another study still in Algeria in 2013, their value was
3.8 /W (Bouzidi, 2013). In 1999, the cost of a PV array was 6 /Wp in Algeria (Hamidat, 1999). In
Jordan, another study mentioned a cost of 3.4 /Wp for the solar panels and 0.26 /Wp for the support
structure of the panels based on cost data of year 2004 (Odeh, Yohanis & Norton, 2006). For the Indian
market, the cost of PV modules has decreased from 0.86 /Wp in 2012 to 0.5 /Wp in 2014 (Chandel,
Nagaraju Naik and Chandel, 2015).
For the motor pump, the diversity of prices as well is quite important depending on the location and year
of the study: for example, 2.1 /W (Bakelli, Hadj Arab & Azoui, 2011) or 1024 for the whole motor
pump pumping 60 m3/day at 45 m depth (Bouzidi, 2013) are the costs on the Algerian market. Another
article differentiated the cost of AC and DC pump, 0.09 /Wp was the price of an AC pump and
0.34 /Wp was the price of a DC pump for the Chinese market in 2012 (Campana, 2013).
Some typical examples of the capital costs for the supply and installation of hand pumps are: 3588 for
a Afripump, 1560 for an AfriDev SB pump, 1092 for an AfriDev pump (Bossyns, 2013).
b) Maintenance(costs(
For a solar pump, the maintenance costs are assumed to be annually between 1% of the initial capital
costs (Bakelli, Hadj Arab & Azoui, 2011; Van Meel and Smulders, 1994; Bouzidi, 2013) and 2% of
these initial capital costs (Olcan, 2015; Ould-Amrouche, Rekioua, & Hamidat, 2010). It can reach 0.07%
of the initial capital cost for annual maintenance (Montorfano, Sbarbaro & Mor, 2015). These costs only
concern small repairs and do not include the cost of replacement for the main elements of the systems
such as the motor pump. The lifespan for the motor pump is often said to be 10 years in the literature
(Olcan, 2015; Bakelli, Hadj Arab & Azoui 2011; Bouzidi, 2013).
For hand pumps, with a centralized maintenance system, the annual cost of maintenance of a hand pump
supply system is between 0.43 /year to 1.72 /year per user (Arlosoroff et al., 1988). Well-planned
community-level maintenance can cost as little as 0.0043 /year per pump (Arlosoroff et al., 1988). The
annual maintenance cost of a hand pump is around 0.5% of the total investment cost (Bossyns, 2013).
However, it is difficult to find accurate and reliable data for maintenance costs because most of the
maintenance operations are done by volunteering villagers (Cairncross & Valdmanis, 2006).
In Burkina Faso, the maintenance cost of a hand pump varies depending on the brand and the age of the
pump. However, in order to establish an integrated water management system at the villages or
municipalities, a contribution of 3.8 /household/year is recommended (Agence Française de
développement, 2011). The more a hand pump is used, the quicker it can have a failure and the more
expensive the maintenance is. Hence, maintenance costs must be calculated based on the number of
households using it (Agence Française de développement, 2011). For example, for 300 users, which
corresponds to 30 households using the same pump, the contribution should be 3.8 /household/year
which corresponds to 114 /year (Agence Française de développement, 2011). Table 6 shows an
example of the estimated breakdown of maintenance costs per components of a hand pump. This table
also gives an overview of the main elements that need to be frequently replaced in a hand pump.
&
!"#$%&L(&KH"?@$%&/+&3%<633%*-&OPQ&</.-.&+/3&"*&R*4,"&Q"3=&RR&7"*4&@6?@&5S"30%T&"*4&U%%4J&>V'G9&
&
c) Lifespan((
For solar pumping systems, the physical life considered in the literature is often 20 years. For hand
pumps, it is difficult to find data about the lifespan because fewer economic analyses exist. All the data
encountered in the literature are summarized in Table 7.
Type of
pump
Length of life
(in years)
Source
Solar
pump
101
202,3,4,5,6,7,8
259
1 : Bossyns, 2013 ; 2 : Zhang, Campana, Yang, Yan, 2017
; 3 : Ould-Amrouche, Rekioua, & Hamidat, 2010 ; 4 :
Phiri, Rowley, Blanchard, 2015 ; 5 : Mortorfano, 2016 ;
6 : Odeh, Yohanis & Norton, 2006 ; 7 : Bouzidi, 2013 ; 8 :
Yahyaoui et al., 2017 ; 9 : Girma, 2017
Hand
pump
208
305
5 : DINEPA Haïti, 2013 ; 8 : Parry-Jones, Reed and
Skinner, 2001
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&
However, these lifespans are not necessarily the realistic lifespans. Solar pumps are quite recent so it is
hard to find reliable data on their lifespan. The 20-year European standard life for solar panels is often
considered as the limit for solar pumps. Hence the importance of trying to obtain a value that would be
closer to the reality.
d) Typical(discount(rate((
In several studies, a discount rate of 10% is used (Parajuli, Pokharel and Østergaard, 2014; Bouzidi,
2013; Montorfano, Sbarbaro & Mor, 2015). Sometimes 5% is used as well (Olcan, 2015). In a study
about rural off grid electrification in Burkina Faso, conservative discount rates between 6% and 10%
for PV systems were assumed by the Atlantic Bank Burkina (Ouedraogo et al., 2015).
2.3.3. Review of costs for solar and hand pumps case studies in different countries
Table 8 lists some other case studies found in the literature.
Source
Type
Place
Flow
rate
(m3/day)
Head
Initial
capital costs
()
O&M costs
Agence Française
de développement,
2011
Hand
Pump
Burkina
Faso
1829
Agence Française
de développement,
2011
Hand
Pump
Chad
3060 m
1524
Agence Française
de développement,
2011
Hand
Pump
Chad
80 -100 m
2287
Bossyns, 2013
Hand
Pump
Mozambique
5.8
45 m max
1092
0.5% of capital costs and
2% overhaul after 5 years
Bossyns, 2013
Hand
Pump
Mozambique
4.8
80 m max
1560
0.5% of capital costs and
2% overhaul after 5 years
Bossyns, 2013
Hand
Pump
Mozambique
4.8
100 m max
3588
0.5% of capital costs and
2% overhaul after 5 years
Cloutier and
Rowley, 2011
Hand
pump
Nigeria
8
1374
Kapoeta North
County Rural Water
Service Board,
2014
Hand
pump
Sudan
50 m
11 570
600 850 / year
Loughborough
University, 2015
Solar
Pump
Used by
Water
Missions
International
2385
Abdeen Mustafa
Omer, 2001
Solar
pump
Sudan
25
20 m
5300
Phiri, Rowley and
Blanchard, 2015
Solar
pump
Malawi
70 m
13 682
1884 for pump
replacement (10 years)
190 for annual
maintenance
Bossyns, 2013
Solar
pump
Mozambique
40
40 m
10 829
2% of capital costs and
25% overhaul after 5 years
Bossyns, 2013
Solar
pump
Mozambique
26
70 m
12 318
2% of capital costs and
25% overhaul after 5 years
Bossyns, 2013
Solar
pump
Mozambique
22
100 m
14 105
2% of capital costs and
25% overhaul after 5 years
Purohit, Kandpal,
2005
Solar
pump
India
10 m
9 000
20 / year
Hamidat, 1999
Solar
pump
Algeria
43
14.5 m
7 807
1% of capital costs
annually
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All the costs have been converted into euros. The most striking conclusion that can be drawn from this
review of case studies is that the initial capital costs are increasing with the head of the pump.
The levelized cost of water is another criteria of economic viability used in many articles. For deep
boreholes (100 m head boreholes), solar PV systems and hand pumps have similar costs of water of
respectively 0.27 /m3 against 0.26 /m3 of water (Bossyns, 2013). This is due to the high price of the
Afripump, which is almost 4000. This does not take into account the need for more boreholes in the
case of hand pumps which will make this solution even more expensive compared to solar pumps for
deep boreholes (Bossyns, 2013). In the case boreholes capacity are too low and their numbers has to be
increased whether it be with hand pumps or solar pumps, both solutions are competitive. For small
population where only one borehole is enough, hand pumps are the preferred solution from an economic
perspective (Bossyns, 2013).
Other studies have calculated the cost of water. In India, in 2005, the cost of water extracted with a
PVWPS of a capacity of 1.8 kWp was 0.025 /m3 (Purohit & Kandpal, 2005). In Algeria, for a flow rate
of 43 m3/day, the cost of water is 0.034 /m3 in 1999 (Hamidat, 1999). The LCOW is 0.055 /m3 in
2017 (Girma, 2017).
2.4. Benefit analysis of solar pumps and hand pumps
2.4.1. Benefit analysis methodology
Benefit analysis of water extraction techniques is usually carried out through surveys of the local
population, which can help assess household’s use of improved drinking water (WHO and UNICEF,
2006). Well-structured questionnaires can be administrated to local population and in-depth interviews
can also be carried out with stakeholders (Emenike et al., 2017). Interviews give a better and more
precise idea of people’s feeling about their access to water (Emenike et al., 2017).
A harmonized set of questions for drinking water, set by the World Health Organization and UNICEF,
gives information about the type of water source used by each household, the time required to collect
water, and the person responsible for collecting water and the potential treatment of water (WHO and
UNICEF, 2006). Other factors are also considered such as the perceived quality of collected water, the
availability of water during all seasons and the cost of water (WHO and UNICEF, 2006).
However, studies concerning benefit of using a solar pump rather than a hand pump are rare. For
example, no study that compares the arduousness of using a hand pump or a solar pump could be found.
2.4.2. A comparative analysis of the benefits of hand pumps and solar pumps
Hand pumps and solar pumps are to be installed on protected hand-dug wells (only for hand pumps) or
boreholes. Both of these water sources are considered as improved ones and the water quality is the
same (WHO/UNICEF, 2010). From this health point of view, they are on equal basis; solar pumps do
not bring better water quality than hand pumps.
However, the question of arduousness of work has to be raised. Few studies exist about the difference
of human energy needed in the case of hand pumps or solar pumps. But as pumping lift increases, it
becomes harder and harder to pump water with a hand pump (Arlosoroff et al., 1988). This increases
comparative advantages of solar pumps in terms of effort to access water. But in both cases, the burden
of carrying the water from the pump to households is to be considered.
Some studies have shown that improving water quality brought fewer benefits than improving water
quantity (Cairncross & Valdmanis, 2006). Solar pumps usually have a higher flow rate than hand pumps
for the same head (Bossyns, 2013). But this has to be mitigated because, in both systems, water has to
be carried from the pump to the houses so the quantity collected in the end is not necessarily larger in
the case of solar pumps. Indeed, the impact of water supply is dependent on the distance between the
house and the pump (OECD, 2011). But solar pumps are the first step towards the installation of piped
water systems. With these piped water systems, no need to walk to the water point.
From an economic point of view, it is interesting to consider the cost of extra borehole construction.
Hand pumps require a lower investment per installation but their output in term of flow rate, for the
same head, is often lower than the one of solar pumps (Bossyns, 2013). Their flow rate is capped to
0.3 L/s (MacDonald et al., 2012). Consequently, for a given volume required, more boreholes may be
needed if they are mounted with hand pumps than with solar pumps. Moreover, regarding maintenance,
even though maintenance costs for hand pumps are generally lower than for solar pumps (Bossyns,
2013), hand pumps break down more easily than solar pumps (WaterAid, 2013, Phiri, Rowley and
Blanchard, 2015). In Sub-Sahara Africa, around half of hand pumps are out of order (OECD, 2011).
This means that if maintenance work is not carried out properly and regularly enough, hand pumps are
more likely to be out of order and solar pumps may be a more sustainable alternative.
2.5. Conclusion
Access to water in developing countries and especially in sub-Saharan countries is an extremely urgent
issue to tackle, as many sub-Saharan countries, including Burkina Faso, are still lagging behind in terms
of improved water supplies.
This literature review described and compared different groundwater extraction techniques, widely used
in sub-Saharan Africa. This comparison led to the choice of studying solar pumps and hand pumps. The
capital costs of hand pumps are usually much lower. However, for certain cases, solar pumps may be
cost-competitive, especially for deep boreholes that require more power to collect water.
The main gap identified in the literature is a comparison between solar pumps and hand pumps in terms
of costs and benefits. Another gap that has been identified is that most economic studies focus on a case
study or work with cost assumptions.
In this thesis, an estimation of the life cycle cost and levelized cost of water for hand pumps and solar
pumps will be performed. Instead of focusing on a case study, we chose to analyse a range of pumping
systems. Finally, to avoid cost assumptions, data are collected from suppliers and maintenance
technicians of hand and solar pumps in Burkina Faso.
Chapter 3 Research methodology and data collection
3.1. Introduction
This study aims at developing a methodology to compare economically photovoltaic (PV) water
pumping systems to hand water pumping systems, and then conduct this economic analysis in the
context of a rural region of Burkina Faso. The complete economic evaluation of pumping systems for a
particular location and water demand must include both capital cost and recurrent costs (maintenance
and replacements).
Four main objectives have been identified for this thesis:
- Find out the initial capital cost for solar pumps and hand pumps with data collected in Burkina Faso.
- Identify the maintenance costs associated with each type of pumping system.
- Calculate the present value of those recurrent costs, with the discount rate chosen, in order to obtain
the life cycle cost and the levelized cost of water for any solar pump and hand pump in the context
of Burkina Faso.
- Find out the influence of the lifespan, the flow rate of water and the discount rate on the levelized
cost of water of both systems, by performing a sensitivity analysis.
The economic assessment was based on two main analyses: the life cycle cost (LCC) analysis taking
into account the time value of money of each cost occurring during the lifespan of the project and also
the levelized cost of water. A sensitivity analysis was then conducted to evaluate the impact on the cost
of water of the following parameters: the flow rate of water, the discount rate and the lifespan of the
system.
3.2. Methods used
Three main steps were followed in this study and will be described in this section: firstly, a technical
analysis, then an economic analysis and, to conclude, a sensitivity analysis.
3.2.1. Technical analysis
a) Architecture(of(the(systems(
Defining the architecture of both systems is done with the literature. After this step, the main elements
of the pumping systems are known. This is very important to define the framework of the study.
b) Boundary(conditions((
The sizes of the system have to be precisely defined. The range of total dynamic heads and flow rates,
that are covered by the systems, are defined with an exploratory analysis. In order to do a valid
comparison, only systems of similar sizes are studied in this thesis. Large scale PVWPS for distribution
networks are not considered here but only standalone systems for rural communities.
c) Sizing((
Accurately sizing the system is a key step to build the model for initial capital cost calculation. An
original approach to evaluate the costs was chosen: quotations were asked to different local suppliers in
order to find out how they would dimension their systems. For instance, for a PVWPS, it allows to find
out the size of the PV modules and of the tank they would install for a given flow rate and total dynamic
head.
d) Estimating(the(lifespan((
It is necessary to clearly define the different steps of the life of a pumping system when it comes to
calculating the life cycle cost of the system. As illustrated in Figure 3, for any water supply project, the
life of the asset can be divided into 5 main stages that are predevelopment and consenting, production
and acquisition, operation and maintenance, decommissioning and disposal.
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For the particular case of installing a pump in a developing country, very few data are available for
phase 1 and 5. The assumption is made that no decommissioning exists for pumps in Africa (Odeh,
Yohanis & Norton, 2006; Bouzidi, 2013) and that the costs associated with phase 1 (Predevelopment
and Consenting) are negligible compared with the other costs. Accordingly, the analysis for life cycle
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costing will focus on phase 2 to 4, between the production and acquisition of the different elements of
the pump and the operation and maintenance until its end of life. The lifespan of the whole pumping
systems used in the economic analysis is the mean value of the lifespans collected from the literature
and from the field trip.
3.2.2. Economic analysis
a) Initial(capital(costs((
The first step of the economic analysis is to model the initial capital expenditures for hand pumps and
solar pumps which is done with the following stages:
1. Identify the cost items from the architecture of the system that has been previously defined with
the help of literature and cost details from quotations.
2. Build the model to calculate the initial capital costs. The model built in this study requires three
inputs for a PVWPS: the expected flow rate of water that is specified depending on the needs
of the community, the number of days of storage needed in the reservoir and the distance from
the capital city. It requires only one input for a hand pumping system, which is the distance
from the capital. The capital of the country is chosen as the reference because most of the
companies bring the drilling machinery from the capital, Ouagadougou in the case of Burkina
Faso.
3. With all the data collected, find the average cost of each cost item.
4. When the cost depends on an input of the model, data are fitted with a linear model to obtain an
equation. This is done in the sizing part of the technical analysis.
5. Compute the initial capital costs for each pumping system.
b) Maintenance(costs((
The maintenance costs are then estimated with different sources from the literature and from interviews
performed during a field trip. The following methodology was followed in this study:
For hand pumps:
a. Identify the main wearing parts of the pump that need to be replaced after a few years and
find the replacement cost and frequency of replacement for each one.
b. Determine the price of the workforce and transport for each intervention
c. Compute annual maintenance costs.
For solar pumps:
a. Find the annual maintenance costs for small repairs given in the literature. It is given as a
percentage of the initial investment cost.
b. Identify the main wearing parts of the pump that need to be replaced after a few years and
find their replacement cost and frequency of replacement.
c. Compute annual maintenance costs.
c) Discount(rate((
The discount rate formula includes the interest rate W0 and inflation rate $. It is defined as:
W = X > W0X > $ Y X**(Riggs et al., 1996)
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d) Life(cycle(cost(and(levelized(cost(of(water((
A life cycle cost analysis is the estimation of the different costs over the whole life of an asset, taking
into account the discounted value of the future costs. Once the maintenance costs have been estimated,
the net present value of those costs are calculated using a discount rate, with Equation 6. The discounted
values of maintenance costs are summed up with the initial capital costs (Equation 7) to get the life cycle
cost of the pumping system.
The levelized cost of water is the life cycle cost of a project divided by the output water obtained during
the life of the project as shown by Equation 9. The output of water is the theoretical volume delivered
by the pumping system.
3.2.3. Sensitivity analysis
A sensitivity analysis is then conducted to find the influence of certain parameters on the results. The
influence of technical parameters such as the lifespan of the pumping system and the flow rate but also
the influence of economic parameters such as the discount rate are further investigated. The aim here is
to calculate the levelized cost of water while one or two parameters, among the three studied, are
varying. This sensitivity analysis is conducted on Excel and plotted on MATLAB.
3.3. Data collection
To analyse the two types of pumping systems, a literature review has been done to gather information
on the architecture of the systems, the lifespan of the elements and the costs that could be found in the
literature. Then, data collection was performed during a field trip to Burkina Faso. This field trip aimed
at collecting data for both PVWPS and hand pumps, on the costs and lifespan of each element, as well
as information on frequency and cost of maintenance for both systems. Indeed, the output of this
economic assessment highly depends on the quality of the data.
3.3.1. Case study details
One of the specificities of this study is the use of local data collected in several locations of Burkina
Faso to perform a precise and accurate economic analysis. Data collection took place between the 12th
June 2018 and the 3rd July 2018.
The different locations were:
- Ouagadougou, Province of Kadiogo, Centre Region.
- Tenkodogo, Province of Boulgou, Centre-East Region.
- Garango, Province of Boulgou, Centre-East Region.
- Gogma, Province of Boulgou, Centre-East Region.
In order to achieve the goals defined in the methodology, the data collection must allow to get an
overview of the different costs associated with both pumping systems for the case of Burkina Faso, to
understand the frequency and cost of maintenance, to obtain more precise information about the real
lifespan of the systems and also to identify the preferences of the users in terms of water extraction
techniques.
3.3.2. Primary data acquisition
A questionnaire was prepared to collect primary data during the field trip (see Appendix). The first part
of the questionnaire aimed at collecting prices and expected lifespan for the main elements of both hand
pumps and solar pumps. The second part of the questionnaire was a structured interview including
questions on the cost of installation, frequency and cost of maintenance, as well as questions regarding
the choice between solar pumps and hand pumps and preferences of the users.
a) Cost(gathering(methodology((
A crucial part of data collection was to obtain accurate costs for the different elements of the pumping
systems. This part of the data collection was carried out among Burkinabe suppliers and installers of
solar and hand pumps. Quotations and invoices were collected, allowing to have a precise view on all
the initial capital costs that have to be paid by anyone wishing to install a pumping system in Burkina
Faso.
- For hand pumps, 15 quotations and invoices were obtained from different suppliers. Those
quotations and invoices were issued for existing projects that took place between 2015 and 2018.
- For solar pumps, 7 quotations and invoices from existing projects that were installed between 2016
and 2018, were obtained from different companies.
b) Current(prices(–(Quotations(on(any(solar(pumps(
To get more data on the cost of solar pumps, quotations were asked to companies installing solar pumps,
pretending that a solar pump was to be constructed in the village of Bidiga, department of Tenkodogo,
Province of Boulgou. As shown in Table 8, different depths and flow rate were asked to each supplier
to get a larger range of prices. These depths and flow rates come from the definition of the boundary
conditions. Normally, a geophysical study would have had to be done to find out the real flow rate of
the borehole and hence to give a more precise estimation of the prices. Obviously, this geophysical study
could not be done in this case.
Companies which provided
quotes
Total Dynamic
Head
Flow rate
CB Energie
5 m
5 m3/day
Yandalux Burkina Faso SARL
15 m
5 m3/day
Sahel Energie solaire
15 m
10 m3/day
Soleil Plus
15 m
20 m3/day
Energy and Services
35 m
5 m3/day
Générale de Travaux Burkina
35 m
10 m3/day
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c) Structured(interviewing(–(local(suppliers(and(stakeholders(
Twenty interviews were conducted in total. The target interviewees were: hand pumps and solar pumps
suppliers (5 different companies in Garango, Tenkodogo and Ouagadougou), technical managers for the
maintenance of hand pumps in the region of Garango (3 interviews), local market vendors (8 shops in
Garango and Tenkodogo) and relevant authorities and organisations working in the water sector of the
region (water and sanitation decision makers from the municipality of Garango, from the regional office
and from a NGO called Dakupa). More details about the interviewees can be found in Table 9.
Date of the
interview
Name
Profession
Name of the company
16/06/2018
Zeba SOUKOULA
Maintenance technician hand
pumps
16/06/2018
Fernand LINGANI
Hand and solar pumps supplier
Forex
17/06/2018
Amadou
KOUDOUGOU
Manager of a solar pump
Gogalis
18/06/2018
Joanny BAMBARA
Water and sanitation manager
Municipality of Garango
18/06/2018
Albert BAMBARA
Maintenance technician hand
pumps
19/06/2018
Ferdinand
KADOURE
Responsible for water and
sanitation
DAKUPA
21/06/2018
G Joseph BALIMA
Hand and solar pumps supplier
Balima Ingénieurie
Technologie
21/06/2018
Local market vendor
Quincaillerie Bagdad et
Frères
21/06/2018
Fidèle QWAMA
Water and sanitation manager
Regional direction of water
and sanitation
22/06/2018
Goumané
BOUKARE
Local market vendor
22/06/2018
Israël KAMPANE
Local market vendor
22/06/2018
Rassidou
BAMBARA
Local market vendor
22/06/2018
Arouna
YOUGBARE
Local market vendor
22/06/2018
Bilal ZAKARIA
Local market vendor
22/06/2018
Amadou NOMBRE
Local market vendor
22/06/2018
Assein DARGA
Local market vendor
27/06/2018
Joseph NYANKINE
Maintenance technician +
supplier hand pumps
Etablissement Himinga
02/07/2018
Ahmed ZEBA
Hand and solar pumps supplier
BETIA SARL
03/07/2018
Joachim KINDA
Solar pumps supplier
K&K
03/07/2018
Jean-Christophe KI
Hand pumps supplier
Vergnet Hydro
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3.3.3. Secondary data
A literature review was done to better understand the components of the two pumps in order to conduct
a detailed and complete cost analysis. The literature review also provided cost data that were used in the
analysis, when not enough data could be found on the field. This was particularly true concerning the
lifespan and maintenance of solar pumps. This may be explained by the fact that this technology is still
quite new and less widespread than hand pumps.
3.4. Conclusion
The methodology of this research project has followed three main steps. Firstly, a technical analysis of
both pumping systems was done and led to a detailed economic analysis. Eventually, a sensitivity
analysis was conducted to find out the influence of certain parameters on the economic indicators. The
three next chapters will each correspond to a step of this methodology.
Chapter 4 Solar and hand water pumps: a technical analysis
4.1. Introduction
This chapter aims at setting the framework for the studied systems. A precise description of both systems
will help to identify all the initial investments necessary for each pumping system. The technical design
of each pump has been obtained with secondary data sources from the literature. For solar pumps, the
quotations obtained were also used to find out the main elements of the system that must not be forgotten
in the cost analysis. Then the boundary conditions for the system were defined as well as the sizing of
the system. In the last part of this chapter, the technical lifespan of the systems is investigated. This will
be useful in the economic analysis of the next chapter.
4.2. Architecture of the systems
4.2.1. Hand water pumps
Many different manual pumping systems are used in Africa. In Burkina Faso, the most used systems are
INDIA Mark hand pumps. Figure 4 highlights the main parts of INDIA hand pumps, which are made
up of many moving parts.
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4.2.2. Solar water pumps
Two types of PV pumping system configurations exist. The first configuration is a battery coupled PV
pump, in which the PV panels charge the battery and the battery is connected to a DC pump or to an AC
pump through an inverter. But batteries have a low lifespan and have to be replaced frequently which is
not suitable for rural poor villages and lowers the suitability of the system. The second configuration is
a direct coupled PV pumping system where the PV panels directly drive the motor pump. In this
configuration, there is no need to store electrical energy and the cost is reduced. Water is stored in a
large reservoir. This type of system is suitable in sites with good solar irradiation throughout the year
which is the case in Burkina Faso (Girma, 2017). The main options in Burkina Faso are either a metallic
tank or a polytank which is made of plastic. It is best if the tank is located near the well and standpipes
because it will reduce the costs, as the hydraulic system required is reduced.
This study focuses on the case of direct coupled PV pumping systems with a polytank to store water.
Five main parts are considered in Table 10:
PV array:
PV modules
Connection cables
Support structure
Pump:
Motor pump
Controller
Level sensor
Hydraulic system:
Pipes
Taps
Standpipe
Storage unit:
Tank
Structure for the tank
Others:
Fence
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Figure 5 gives an overview of how the different elements of a solar pump are connected to each other.
The PV panels are connected to a controller. The controller starts and stops the motor pump depending
on the level of water in the reservoir, which is obtained with a level sensor. The sub-system converter
motor – pump is submerged in the borehole. A piping system connect the pump with the tank and the
tank with the stand pipe where users can collect water by using taps (Meunier et al., 2018).
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4.2. Boundary conditions
From an explanatory analysis, asking local suppliers, a maximum flow rate of 30 m3 /day was established
for the study. When quotations were asked in order to find the correct sizing of the systems a maximum
total dynamic head of 35 m was used. This was chosen after an exploratory analysis as well and to match
the maximum depth at which a hand pump can be installed. Indeed, the limit for hand pumps in terms
of depth is around 45 meters (WaterAid, 2013). This study aims at comparing both systems and it would
not make sense to include conditions in which one of the two systems is not technically feasible.
4.3. Sizing of the solar pump
This section only focuses on solar pumps because hand pumps are standardized and cannot be sized
depending on the flow rate required for the community. To dimension the systems, quotations were
asked to suppliers and installers of solar pumping systems, pretending that an association wanted to
install a solar pump in a village of Burkina Faso.
4.3.1. Price of transporting the drilling material
Transporting the drilling material accounts for a non negligible part of the drilling of the borehole. This
equation was obtained from a linear regression of all the data collected. For each quote, the distance
between the location of the pump and Ouagadougou was obtained and this gave a pair (distance, price
of transport for the drilling material). A linear regression on Excel gave the following equation:
#$,1&2% = Xwx*y
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The distance D is an input of the model to calculate the initial capital costs.
4.3.2. Power necessary from solar panels as a function of the hydraulic energy
This variable is the power necessary for the pump to pump water and it determines the number and
power of the PV panels. The required power to pump water, which is a function of the vertical head
TDH and the water flow rate, is:
# = * zw{z|**}**~y•
8
**•‚-/ƒ5-
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and
89= *:**„**}**~y&
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so
#= * 89
…†‡‡*8
*•‚-/ƒ5-**&
KC6"-,/*&'>
where: TDH is the sum of the static water level, the height at which water enters the tank and the
additional head associated to pipe losses. The sum of the height at which water enters the tank and the
additional head associated to pipe losses is taken equal to 7 m for this study. This value comes from the
observation of local systems.
89 is the hydraulic energy necessary to lift the water.
8
is the average irradiation of the less sunny month, it is equal to |ˆe‰ uŠtmi (LeLab by SINES).
‚-/ƒ5- = * •()20‹,4",4'/"/4 %&'%, the yield of all the subsystems, is not known and has to be
obtained.
With the sizing software SINES, it is possible to size a solar pumping system with three input data: the
location (and thus the solar irradiation), the total dynamic head (in metres) and the required flow rate
per day. This simulation was done several times with different values of TDH and flow rates of water.
The location was fixed at Ouagadougou.
The simulation gives:
# = Xw|*X‡Œ• *89
KC6"-,/*&'F&
Comparing this equation given by the simulation and the theoretical expression, *•‚-/ƒ5- can be
calculated. *•‚-/ƒ5- =…{Ž in this case.
The energy necessary to pump water deduced from Q and HMT and Equation 12 and hence the nominal
power of solar panels necessary to pump water is obtained from Equation 14. Once the power needed is
known, the number of solar panels can be figured out. It is possible to calculate the price of the pump
and the solar panels depending on these figures and with the data obtained.
4.3.3. Price of the solar panel as a function of the installed PV power
The data used in this section come from all the quotes and invoices collected for solar pumping systems.
As shown on Figure 6, sixty data points were used to determine the price of the solar panels as a function
of the power installed:
#$() = ‡w†|*#() > …wz
KC6"-,/*&'G&
&
:,163%&L(&_3,<%&/+&"&_`&?/46$%&".&"&+6*<-,/*&/+&-7%&@/2%3&
&
4.3.4. Price of PV modules support structure as a function of the power installed
As shown on Figure 7, eleven data points were used to determine the price of the structure for the PV
modules as a function of the PV power installed:
#$()*+" = ‡w‡•†*#()
Equation 15
y!=!0,65x!+!3,2
R²!=!0,54
0,00
50,00
100,00
150,00
200,00
250,00
300,00
350,00
400,00
450,00
050 100 150 200 250 300 350
Price!()
Power!(W)
&
:,163%&M(&_3,<%&/+&-7%&.-36<-63%&_`&?/46$%.&".&"&+6*<-,/*&/+&-7%&@/2%3&/+&-7%&?/46$%&
4.3.5. Price of the pump as a function of the PV power installed
As shown on Figure 8, seven data points were used to determine the price of the pump as a function of
the power installed with the solar panels:
#$
%&'% = Xwz*#() > Xw|*X‡v
Equation 16
&
:,163%&X(&_3,<%&/+&"&?/-/3&@6?@&".&"&+6*<-,/*&/+&-7%&*/?,*"$&@/2%3&/+&-7%&_`&@"*%$.&
&
However, this model could certainly be improved as it is not obvious that the price of the pump and the
power of the panels can be linked as they are here.
&
&
y!=!0,086x
R²!=!0,25
0,00
10,00
20,00
30,00
40,00
50,00
60,00
70,00
80,00
90,00
050 100 150 200 250 300 350
Price!()
Power!(W)
y!=!1,2x!+!1.5!103
R²!=!0,88
0,00
500,00
1000,00
1500,00
2000,00
2500,00
3000,00
3500,00
4000,00
4500,00
0500 1000 1500 2000 2500
Price!()
Nominal!power!of!the!PV!panels!(W)
4.3.6. Size of the tank
The number of days of storage required, N, is an input of the model. Then the equation of the model to
find the size of the reservoir becomes !
"50E = *}*Z* where Q is the daily flow rate required for the users.
A 1-day storage is often considered for pumping projects (Olcan, 2015) so N = 1. However, it has been
seen from field observations that no polytank installed had a capacity of more than 10 m3. Hence, it has
been chosen in the model that:
!
"50E =•‘’]}*“” *X‡*uv^
KC6"-,/*&'M&
4.3.7. Price of the tank as a function of its size
To simplify the study, only polytanks are considered and not steel reservoirs in this study. Steel
reservoirs are usually more expensive. The linear regression is shown on Figure 9.
Ten data points were used to determine the price of the reservoir as a function of its capacity:
#$?50E = ‡wz…*!?50E
KC6"-,/*&'X&
&
:,163%&N(&_3,<%&/+&"&@/$T-"*=&".&"&+6*<-,/*&/+&,-.&<"@"<,-T&
4.4. Lifespan of pumping projects considered in the analysis
The lifespan of a pump is the period during which the pump is used. At the end of it, the pump is
abandoned, often because it is broken and cannot be repaired. Realistic lifespans for pumping systems
have to be considered. Indeed, estimating the lifespan of a pumping system is crucial because it will
have a huge influence on the economic viability of the system.
y!=!0,23x
R²!=!0,90
0,00
500,00
1000,00
1500,00
2000,00
2500,00
02000 4000 6000 8000 10000 12000
Price!()
Capacity!(L)
Table 11 summarizes the lifetime of pumping systems considered in different sources of the literature
and obtained in the questionnaires.
Type of
pump
Length of life
(in years)
Considered
value
Source
Solar pump
101
202,3,4,5,6,7,8
259
20
1 : Bossyns, 2013 ; 2 : Zhang, Campana, Yang, Yan,
2017 ; 3 : Ould-Amrouche, Rekioua, & Hamidat,
2010 ; 4 : Phiri, Rowley, Blanchard, 2015 ; 5 :
Mortorfano, 2016 ; 6 : Odeh, Yohanis & Norton,
2006 ; 7 : Bouzidi, 2013 ; 8 : Yahyaoui et al., 2017 ;
9 : Girma, 2017
Hand pump
51
202,3,8
304,5
406
607
25
1: Ahmed Zeba, 2018; 2: Joanny Bambara, 2018; 3:
Ferdinand Kadouré, 2018; 4: Fidèle Qwama, 2018;
5: DINEPA Haïti, 2013; 6: Albert Bambara, 2018; 7:
Joseph Nyankine, 2018; 8: Parry-Jones, Reed and
Skinner, 2001.
!"#$%&''(&W,+%.@"*&/+&./$"3&@6?@.&"*4&7"*4&@6?@.&5"6-7/38.&-"#$%9&
However, this assumption will be discussed in another chapter. Indeed, even if the technical lifespan of
a system can be very long, a much shorter lifespan has sometimes to be considered, representing the
time during which the pump is effectively being used. The lifespan of a pumping system does not only
depend on the technology but also on the quality of maintenance. In this study, an assumption is that
maintenance is done by qualified technicians and that the technology is well used. In many situations,
the lifespan can be very short due to a lack of adequate maintenance or abusive usage: hand pumps break
much more often than solar pumps.
4.5. Conclusion
The architecture, boundaries, sizing and lifespan of both systems investigated in this chapter are
essential to define the framework of the economic analysis of the next chapter. In this chapter, the sizing
of hand pumps is not mentioned because they are considered as standardized in this study. In reality, the
choice of a hand pump depends on the depth of the borehole. But the variation of the prices depending
on the model chosen is assumed to be small, as it has been seen in the literature review. This is why the
depth is not taken as an input of the model as it could have been. For solar pumps, only direct-coupled
PV systems are studied. The reservoir is a polytank, which is the cheapest option of tank. However, steel
reservoirs could also be installed.
Chapter 5 Life cycle cost for solar and hand pumping
systems
5.1. Introduction
In this chapter, the complete economic evaluation of the two pumping systems is done, with the help of
data from the literature and from interviews performed during a field trip to Burkina Faso. Typical sizes
have been chosen for the systems. In a first part, the initial capital costs are calculated. Then the
maintenance costs over the whole life of the assets are determined. In a third and fourth part, the choice
of the length of life and of the discount rate used in the analysis is explained. Finally, the results for the
LCC and levelized cost of water calculation are exposed in the last part of this chapter.
5.2. Initial capital costs
The first step for an economic analysis is to determine the initial investment needed. In this purpose, a
breakdown of all those initial costs have to be made for the studied system. This has been done based
on the architecture defined in the section 2 of chapter 4.
5.2.1. Estimating the initial capital costs for hand pumps
The initial investment costs items for a hand pump are defined as follows:
1. Geophysical studies
2. Borehole
a. Preparation, supply and withdrawal of the drilling material
b. Drilling
c. Air lift development
d. Pumping tests
e. Water analysis
3. Pump
a. Preparation, supply and installation of the hand pump
b. Preparation, supply and installation of other equipment (nameplate…)
4. Civil engineering
a. Preparation, supply and installation of the well coping
b. Preparation, supply and installation of the superstructure
c. Preparation, supply and installation of the access ramp
This study will focus only on stainless steel hand pumps for a limited depth of water of 50 meters, which
is the maximum recommended lift for INDIA hand pumps. In Burkina Faso, the estimated depth to
groundwater is estimated between 0 and 25 meters below ground level (Mac Donald, 2012). INDIA
hand pumps are among the most used hand pumps in Burkina Faso. They can be made from galvanised
steel or stainless steel.
With the initial investment costs items mentioned previously, the capital costs of installing a hand pump
in Burkina Faso can be calculated with the data obtained on the field trip. For hand pumps, the capital
cost does not depend on the depth or the flow rate of the pump, as it does for motorised pumps.
Therefore, the calculation of the capital cost in the case of a hand pump is straightforward with the data
already collected. Nevertheless, the capital costs depend on the distance to the nearest technician
because of the cost of the transport.
With Excel, the initial investment is calculated, taking the mean value of all the data obtained for each
component of the cost breakdown mentioned at the beginning of this part. The results obtained here are
described in section 5.5.
The flow rate of a community hand pump is approximately 0.1 0.3 L/s (MacDonald et al., 2012).
During 24 hours, this represents 9 26 m3/day. In Burkina Faso, as the water is not very deep compared
to other African countries, the values of 0.3 L/s and 26 m3/day are taken for the study. For a domestic
utilization, hand pumps are used 365 days a year and between 1 and 12 hours a day (Van Meel and
Smulders, 1994). If the maximum number of hours a pump is used is 12 hours, it corresponds to a
maximum utilization factor of 0.5 and a flow rate of 13 m3/day, which has been considered in the study.
This will be discussed in the sensitivity analysis.
5.2.2. Estimating the initial capital costs for PVWPS
The initial investment cost items for a solar pump are defined as follows.
1. Geophysical studies
2. Borehole
a. Preparation, supply and withdrawal of the drilling material
b. Drilling + equipment
c. Air lift development
d. Pumping tests
e. Water analysis
3. PV array
a. Preparation, supply and installation of the PV modules
b. Preparation, supply and installation of the connection cables
c. Preparation, supply and installation of the support structure
4. Pump
a. Preparation, supply and installation of the motor pump
b. Preparation, supply and installation of the controller
c. Preparation, supply and installation of the level sensor
5. Hydraulic circuit
a. Preparation, supply and installation of the pipes
b. Preparation, supply and installation of the standpipe and taps
6. Water storage
a. Preparation, supply and installation of the tank
b. Preparation, supply and installation of the tank support structure
7. Civil engineering
a. Preparation, supply and installation of the fence
b. Other
The maximum flow rate of a solar pump can vary a lot and has an influence on the capital cost that
cannot be neglected. Indeed, a higher flow rate of water means that the pump will need more power
from solar panels and thus the system will be more expensive. For hand pumps, the maximum flow rate
is limited by the maximum energy that can be supplied by a person so the variation is less important.
This model takes three variables as inputs: the expected flow rate of water that will be fixed depending
on the needs of the community, the number of days of storage needed in the tank and the distance
from Ouagadougou.
The total dynamic head that will vary depending on the location of the pump, is considered as a
parameter here and is fixed at 20 m. Indeed, the depth of water in Burkina Faso is estimated between 0
and 25 m below ground level (MacDonald et al., 2012). The mean value is taken and water is assumed
to be on average at 13 m below ground level. 7 meters are then added to take into account the height of
the reservoir and the pipe losses.
The parameters that will vary with those inputs are: the price of transporting the drilling machinery
(depending on the distance from Ouagadougou), the size of the tank (depending on the number of days
of storage required), the power necessary from the solar panels (depending on the flow rate), the
structure for the panels (depending on the power from solar panels), the pump (depending on the power
from solar panel).
With the data collected during the field trip, equations are obtained and explained in the “sizing” part of
the previous chapter. All the costs include the installation cost. They are then introduced in the model.
The following graph is a schematic of the model done to calculate the initial capital cost of installing a
solar pumping system when the users’ needs and the location are known.
&
5.2.3. Results
a) Hand(pumps((
With Excel, the initial capital costs are calculated, taking the mean value of all the data obtained for
each component of the cost breakdown mentioned at the beginning of this part. The investment cost of
each element of the pump is based on literature reviews, local market surveys as well as invoices and
quotations provided by local suppliers. All the cost figures mentioned in this article have been converted
into euros. Table 12 shows the average value of all the costs considered in this study.
Cost items
Average cost ()
Geophysical studies
7.2 101
Preparation, supply and withdrawal of the
uudrilling machinery
1.9 D where D is the distance between the pump
and Ouagadougou
Drilling + equipment of the borehole
4.6 103
Airlift development
4.2 102
Pumping tests
3.5 102
Water analysis
1.7 102
Total Borehole
5.5 103
Preparation, supply and installation of the
hand pump
1.1 103
Preparation, supply and installation of the
uuwell coping
2.6 102
Preparation, supply and installation of the
uusuperstructure
5.6 102
Preparation, supply and installation of the
uuaccess ramp
2.2 102
Total civil eng