Solar, ,manual and diesel powered pumps

MCGILL UNIVERSITY

Solar, manual and diesel powered pumps: a feasibility, economical and sustainability comparison to provide water to remote rural areas
CCOM 206

Heidy Botero Villegas

15/03/2013

TABLE OF CONTENTS

1.

ABSTRACT ............................................................................................................................ 3

2.

INTRODUCTION ................................................................................................................... 3

3.

BACKGROUND ..................................................................................................................... 4

4.

DISCUSSION .......................................................................................................................... 5

3.1 Hand pumps .............................................................................................................................. 5
3.2 Diesel pumps ............................................................................................................................. 6
3.3 Photovoltaic water pumps or PV systems ................................................................................. 7
3.3.1 Costs....................................................................................................................................... 7
3.3.2 Efficiency ............................................................................................................................... 9
3.3.3 Environmental issues ............................................................................................................. 9
5.

CONCLUSION ..................................................................................................................... 10

6.

ATTACHMENTS ................................................................................................................. 12

6.1 Solar-water pumps .................................................................................................................. 12
6.2 Hand-pumps ............................................................................................................................ 13
7.

REFERENCES ...................................................................................................................... 14

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1. ABSTRACT

Remote rural areas in developing countries lack access to water for crop irrigation and consumption. In order to bring water closer to farmers and families, new technologies, like solarpumps or PV systems have been the most attractive option, due to their low overall costs, high efficiency and environmental friendly operation mode. Hand pumps are a good option to provide water to small villages with widely distributed population, but their efficiencies are low and they can be easily damaged. Diesel pumps can deliver larger water outputs, but, the rising and unstable prices of fuel make them costly to maintain and operate. Additionally, diesel pumps are related to carbon dioxide emissions which are responsible for global warming. Most African countries have good sun exposure through all the year which makes PV pumps an attractive solution to provide clean water to remote rural areas. Additionally, solar-pumps do not require any maintenance, and after few years of operation the initial capital invested can be entirely recovered and the operational costs stayed lower compared to diesel pumps.

2. INTRODUCTION

Billions of people lack access to safe, clean drinking water, and about 2.4 million people die annually due to water related diseases (2). The limited access to clean water in rural areas is a major problem, since water is the most important resource for humans to live. Rural populations depend heavily on water resources for crop irrigation and to fulfill basic needs, like consumption and sanitation. During dry periods, most rural communities have limited access to water, and without water, farmers do not have a means of watering their crops (3). The development of new technologies to provide clean water to farmers and families in remote rural areas had become crucial. 3

In remote rural areas, the access to electricity is limited, thus, traditional electrical pumps are not convenient. On the other hand, manual pumps have very low efficiencies to meet the demand, and diesel pumps become costly in the long term. Therefore, solar-powered pumps are the ideal solution, primarily because sunlight is widely available in remote rural areas (5) and because it is a cost-effective option on a long-term basis (1).
To date, many water pumping systems have been developed, but many challenges still need to be overcome, like the initial costs and the cost for operation (5). Opting for solar-powered pumps or photovoltaic pumps is an attractive solution to provide water to isolated rural areas, but the feasibility of this solution depends upon many factors that will be studied in this paper along with an economical and sustainability comparison with two other types of pumps: manual and diesel. 3. BACKGROUND

In many rural areas in the African continent, women and children spend many hours a day collecting water. Often, they have to travel up to 10Km to a water source, and due to extreme weather conditions, the task becomes very demanding. The time that women and children spend collecting water, are hours that can be devoted to school or other activities. In addition, the amounts of water that individual families can collect are often not sufficient to fulfill their basic needs, or enough to adequately irrigate the land, which leads to dryness, and subsequently to food scarcity and poverty (1).
During dry seasons, surface water becomes unavailable. Consequently, farmers rely mainly on underground water to survive (1). If surface water is available, it is often contaminated which causes water related disease among the population. The problem is how to retrieve water from
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boreholes. The necessity of new technologies to bring water closer to families, has become essential, and with the support of governmental and charity organizations, many solutions have been developed to date. Due to the rapid growth of renewable forms of energy, solar-powered pumps are increasing in popularity (10).

4. DISCUSSION

Due to the demographic distribution, topography and water tables levels, certain difficulties may arise when developing water pumping systems in a given area. A long and tedious study must be carried before deciding the placement and type of pumping system to be installed. The success of a project depend upon many factors, including but not limited to, climate change, initial costs, operation costs as well as the proper care and use from people.

3.1 Hand pumps

Hand pumps are the most popular type of pumping system so far. More than 250,000 hand pumps have already been installed in Africa, but approximately only half are still operational.
“Providing a sustainable water supply to isolated rural populations neither begins nor ends with drilling a borehole and installing a pump.” (Elizabeth Mann, Oxfam Australia, 2003). Many factors are underestimated during the design process of a project, making it difficult to maintain a functional pump. Sometimes, finding the broken parts to replace a damaged pump is very difficult, and in the present, the efforts to overcome this problem have had limited success (6).
Furthermore, the efficiency of human operated water pumps is not sufficient to meet the demand.
In fact, manual pumps are a good option for villages with widely spread population (1).
However, in many remote rural communities, large quantities of water are required to irrigate the

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lands and the water being lifted by human power is not sufficient. A study carried by the department of Civil Engineering of Loughborough University of Technology, where four different manual pumps were selected, and their efficiencies in terms of human power were evaluated, showed that human power for hand pumping is around 50W at a comfortable level (8) which is equivalent to only six to eight meters cube of water collected per day if the pump is operated during seven hours. Even though, manual pumps are usually very cheap compare to other water pumping systems, they had become unsustainable, because instead of repairing existing pumps, new ones are being installed. One must also take into consideration the time that women and children spend pumping water from a borehole and the physical effort that this requires (10).

3.2 Diesel pumps

Diesel water pumps have been an attractive solution to many rural communities in Africa for decades due to the high power inputs achievable. However, there are many constraints associated with diesel pumps. First, the prices of fuel are very unstable and are constantly increasing. In a long-term basis, the needs for fuel as well as the costly maintenance required make this option less attractive for remote rural areas. Beside the economical issues, diesel is not a renewable form of energy; the use of fuel is directly related to carbon dioxide emissions. Also, the machinery used for diesel pumps is generally very heavy, and thus expensive to transport, adding extra costs to the initial capital (9).

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3.3 Photovoltaic water pumps or PV systems

PV systems use solar panels to convert sunlight into electricity. Widely availability of solar energy is crucial for PV systems to work efficiently. In fact, the average daily incoming solar radiation in Africa varies from 5 to 7 KWh/m2/day, which is sufficient to operate a pump (1).
In the following sections, important aspects will be described along with a comparison between the alternative solutions mentioned previously.

3.3.1 Costs

Due to advances in technology, the cost of PV systems has declined since the first solar panel was manufactured. Still, the main issue with PV systems remains their initial costs. Studies have shown that in a long-term basis solar-powered pumps are more viable and cost effective than diesel pumps (9). As can be seen in Figure 1, an operating life of about two years is sufficient to recover the initial capital invested.

Figure 1: Operation life vs. Costs. (Helena M. (2009))

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In remote rural areas, distribution lines extensions can cost a lot of money, thus, conventional electric pumps are not a good option (9). Furthermore, diesel pumps require fuel to operate. The constant supply of fuel to isolated rural zones, as well as the rising and unstable fuel prices makes diesel pumps costly to maintain and operate. On the other hand, the initial costs of solar pumps are still high compare to traditional pumps, but, they have fallen and are set to fall even further due to increasing demand and considerably advance of photovoltaic array technologies.
As can be seen in figure 2 below, on a twenty years operation period, PV systems turn out to be the most cost-effective solution compared to diesel and wind pumps.

Figure 2: Costs comparison on a period of twenty years. (Cloutier, Michael, & Rowley, Paul.
(2011))
It must be noted that, a solar system becomes viable only when it is used on a constant basis.
Basically, demand must be correlated to solar energy availability, meaning that, during the summer months (dry season), when rain is not abundant but solar energy is widely available, more water is needed. However, in areas where demand is not constant, diesel pumps may result in a more cost-effective solution (9)

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3.3.2 Efficiency

The size of the solar array is the product of the efficiency of the solar pump. So, larger arrays have higher electricity outputs, and consequently larger water outputs. Many efforts had been put on the design of solar arrays in order to increase their efficiency without having to increase their size (11). Yet, some improvement still needs to be done. For instance, high losses occur during the conversion of solar energy to electric energy, and for this reason array sizes have to be increased in order to meet the water demands (1). Many solar pumps already existent in the market are presently successfully operating (12).
For small villages, smaller pumps are enough to meet the demand. For instance, “the smallest solar pump requires less than 150W and can lift water from depths exceeding 65m at a 5.7 l/min.” which is equivalent to approximately 8m3 of water per day. Larger pumps can lift water up to 200m head (9); such depths are not achievable with hand pumps. In some cases, delivering high quantities of water require the pump to operate for longer periods, thus, a battery must be required which may add extra costs to the initial capital and maintenance expenses (1).
Nonetheless, if compared to diesel pumps, a PV system produce the same power throughout its life span, while the efficiency of diesel pumps decreases with time (10).

3.3.3 Environmental issues

Solar photovoltaic pumps are a sustainable energy source. In fact, solar pumps require little maintenance and no labor for operation. Given these characteristics, they turn out to be a viable solution to provide water to rural communities in isolated zones of Africa. Diesel pumps are related to carbon dioxide emissions coming from the combustion of fossil fuels which are

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responsible f global warming (10). Figure 3 illustrates the quantities of carbon dioxide emitted by diesel compared to PV pumps (or SPVs).
In the present, promoting and supporting environmental friendly technologies had become a priority for governments and organizations.

Figure 3: Carbone dioxide emissions (Meah, Steven Fletcher, Saudrul Ula (2006))

5. CONCLUSION

Nowadays, remote rural areas in Africa lack access to clean drinking water. Research has been done in order to find solutions to this problem and to improve the quality of life of farmers and thousands of families in developing countries.
In remote rural areas, where families depend heavily on agricultural production to survive, water to irrigate the land is a necessity. For instance, if only manual water pumps were installed, the demand may not meet the supply, and lands will get dry leading to poverty. Even though, manual water pumps are not costly, they are not suitable for remote rural areas because of their low
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efficiency, limited operational depths and labor required to operate them. Additionally, hand pumps can break easily, and their repair often requires special equipment and skills (11).
On the other hand, diesel pumps are related with carbon dioxide emissions. In addition, in a long-term basis, the maintenance costs as well as the constant fuel supply required to operate diesel pumps, make them less cost effective. Finally, photovoltaic pumps are the most attractive option to supply water to isolated rural areas. It has been proven that, even if initial cost are superior, in the long-term PV pumps become cheaper after few years of operation, due to their low maintenance and operational costs. Also, as demand of solar systems increase, costs also decrease. However, the success of a PV system results when sunlight is widely available and when demand is related to solar energy availability; hotter seasons require higher water demands.
Essentially, solar pumps are the most viable option to provide families and farmers with clean drinking water. Farmers will be able to irrigate their lands, families will have access to proper sanitation and the mortality rate associated to water related disease will decrease.

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6. ATTACHMENTS

6.1 Solar-water pumps

Figure 4: Schematic of a solar water pumping system in Sudan (Kala Meah, Steven Fletcher,
Saudrul Ula (2006))

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Figure 5: Photovoltaic water pumping system in Jordan. (Meah, Kala, Fletcher, Steven, & Ula,
Sadrul. (2008))

6.2 Hand-pumps

Figure 6: Scheatic diagramsof four types of hand pumps Lambert R.A., Faulkner, R.D. (1991)
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7. REFERENCES

(1) Cloutier, Michael, & Rowley, Paul. (2011). The feasibility of renewable energy sources for pumping clean water in sub-Saharan Africa: A case study for Central Nigeria.
Renewable Energy, 36(8), 2220-2226. doi: 10.1016/j.renene.2010.12.019
(2) Iro Ong 'Or, Basil Tito, & Long-Cang, S. H. U. (2007). Water Supply Crisis and
Mitigation Options in Kisumu City, Kenya. International Journal of Water Resources
Development, 23(3), 485-500. doi: 10.1080/07900620701488554
(3) Vanderwal, Londa, Rautiainen, Risto, Kuye, Rex, Peek-Asa, Corinne, Cook, Thomas,
Ramirez, Marizen, . . . Donham, Kelley. (2011). Effectiveness, Safety, and Sustainability of a Hand Water Pump Among Women Vegetable Farmers in the Gambia. Journal of
Sustainable Agriculture, 35(4), 394-407. doi: 10.1080/10440046.2011.562053
(4) http://www.sswm.info/category/implementation-tools/watersources/hardware/groundwater-sources/manual-pumping
(5) Whitfield, G.R., Bentley, R.W., Burton, J.D. Cost-effectivness of small solar pumps.
Renewable Energy, Sustainability and the Environment, Elsevier BV, from 1991.
(6) Elizabeth Mann (2003). Sustainable water supply to a remote rural community in
Mozambique. Greener management international. Greenleaf Publishing.
(7) Water Pumps in the Pride Lands: Operation AfriQUA Launches
(8) Lambert R.A., Faulkner, R.D. (1991) The efficiency use of human energy for micro-scale irrigation. Journal of Agricultural Engineering Research 48 (C) , pp. 171-183.
(9) Ramos, J. S., & Ramos, Helena M. (2009). Solar powered pumps to supply water for rural or isolated zones: A case study. Energy for Sustainable Development, 13(3), 151158. doi: 10.1016/j.esd.2009.06.006
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(10)

Meah, Kala, Fletcher, Steven, & Ula, Sadrul. (2008). Solar photovoltaic water

pumping for remote locations. Renewable and Sustainable Energy Reviews, 12(2), 472487. doi: 10.1016/j.rser.2006.10.008
(11)

Kala Meah, Steven Fletcher, Saudrul Ula (2006). Solar power pumping in sudan

rural areas. Renewable and sustainable energy reviews. University of Wyoming, Laramie,
USA.
(12)

Al-Smairan, Mohammad. (2012). Application of photovoltaic array for pumping

water as an alternative to diesel engines in Jordan Badia, Tall Hassan station: Case study.
Renewable and Sustainable Energy Reviews, 16(7), 4500-4507. doi:
10.1016/j.rser.2012.04.033

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References: (1) Cloutier, Michael, & Rowley, Paul. (2011). The feasibility of renewable energy sources for pumping clean water in sub-Saharan Africa: A case study for Central Nigeria. Renewable Energy, 36(8), 2220-2226. doi: 10.1016/j.renene.2010.12.019 (2) Iro Ong 'Or, Basil Tito, & Long-Cang, S (6) Elizabeth Mann (2003). Sustainable water supply to a remote rural community in Mozambique (9) Ramos, J. S., & Ramos, Helena M. (2009). Solar powered pumps to supply water for rural or isolated zones: A case study Meah, Kala, Fletcher, Steven, & Ula, Sadrul. (2008). Solar photovoltaic water pumping for remote locations (11) Kala Meah, Steven Fletcher, Saudrul Ula (2006) Renewable and Sustainable Energy Reviews, 16(7), 4500-4507. doi: 10.1016/j.rser.2012.04.033