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Breaking the mould: solar water pumping—the challenges and the reality
Solar Energy 75 (2003) 1–9
Breaking the mould: solar water pumping—the challenges and the reality q T.D. Short*, P. Thompson School of Engineering, University of Durham, South Road, Durham DH1 3 LE, UK Received 11 May 2002; accepted 30 June 2003
Abstract Solar (photovoltaic) powered water pumping has the potential to bring sustainable supplies of potable water to millions of people in developing countries. Unfortunately, in many cases the application of the pump technology ignores the sociological and economic needs of the users, leading to lack of maintenance, inappropriate financing schemes, inadequate system management and, ultimately, failure of the pump. This paper investigates some of the issues involved in solar water pumping projects, describes the positive and negative effects that they can have on the community and, in proposing an entirely new type of pump, considers what steps could be taken to ensure future sustainability. 2003 Elsevier Ltd. All rights reserved.
1. Introduction For many years, solar (photovoltaic) powered water pumps (PVPs) have been portrayed as the harbinger of a new era in water provision for rural and developing communities. Mass produced pumps and cheaper photovoltaic (PV) panels promised fresh potable water for everyone. Although inroads have been made to reaching this ideal situation, the current reality is somewhat different. There still remain considerable challenges in developing, distributing and applying ‘appropriate’ solar powered water pumps. Solar powered water pumps have the potential to provide significant changes to rural communities—not only through the direct provision of water, but also through the possibilities of sociological and economic development. The impact of PVPs can go beyond the availability of fresh water, but can have both positive and negative consequences. Without knowledge of these consequences it is difficult to see how PVP designers, manufacturers and project implementers can hope to provide a sustainable solution to the problem of water provision. q This paper was presented at the ISES 2001 Solar World Congress in Adelaide, Australia. *Corresponding author. Tel.: 144-191-334-2514; fax: 144191-334-2377. E-mail address: [email protected] (T.D. Short).
This paper will therefore investigate PVPs within the contextual background of ‘appropriate technology’, a design methodology that considers the reasons for technological development and its potential impact on a community. The ideas of ‘village level operation and maintenance’ (‘VLOM’) will be examined, and consideration will be given to how the arising concerns are—or are not—addressed by current designs and operational practices. The paper will then discuss the basic developmental issues that should underpin the design and application of PV powered water pumps and how projects have failed or succeeded because of these issues. Finally, it will consider the development of a novel pump system and how it is being designed in an attempt to ‘break the mould’ by wholly embracing the design philosophy of appropriate technology.
2. Appropriate technology Dr. E.F. Schumacher is quoted by Professor P.D. Dunn as saying ‘A project that does not fit, educationally and organizationally, into the environment, will be an economic failure and a cause of disruption’ (Dunn, 1978). Indeed, this has been seen to be the case in numerous projects throughout the world. In addressing this concern, Dunn uses the expression ‘appropriate technology’ to describe the use of technology in situations that are the
0038-092X / 03 / $ – see front matter 2003 Elsevier Ltd. All rights reserved. doi:10.1016 / S0038-092X(03)00233-0
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opposite to those described by Schumacher. He summarises appropriate technology through the following. The principal aims of development are 1. To improve the quality of life of the people. 2. To maximise the use of renewable resources. 3. To create work places where the people now live. The solutions chosen should satisfy the following criteria 1. Employ local skills. 2. Employ local material resources. 3. Employ local financial resources. 4. Be compatible with local culture and practices. 5. Satisfy local wishes and needs. (Dunn, 1978) Thus a solution making use of appropriate technology must consider—and satisfy—each of the five criteria. Failure to address them is likely to lead to an unsustainable project. Considering Dunn’s criteria, it is clear that whilst the major need of those who are to use a solar pumping system is simply water, there are a number of further issues. Social, economic, health and gender concerns are all directly relevant and yet are often neglected in the design and application of a pumping system. In particular, however, Dunn points out that the solution must be ‘compatible with local cultures and practices’. This demands consideration as to what the local community wants from development as opposed to what aid agencies, for example, think the community want. The question as to whether or not ‘development’ (as understood by ‘more developed’ countries) is required or indeed desired is beyond the scope of this paper. The vast majority of PV pumping systems are developed in ‘Western’ countries where the main design consideration is the cost. In theory, by improving the efficiency of the pump system from PV output to water output (i.e. from ‘wire-to-water’), the number of solar panels required will be reduced and the total pump system will therefore be that much cheaper, broadening its appeal and customer base. Whilst the price of solar panels remains high, this seems a logical approach to furthering the applicability of solar water pumps. Unfortunately it is also a superficial approach, ignoring other factors of potentially greater influence than cost alone. In failing to fully understand the real requirements of, and consequent effects on, the end user, the idea of using ‘appropriate technology’ is largely ignored and solar water pumping remains purely a ‘good idea’.
3. ‘Village level operation and maintenance’ The expression ‘village level operation and maintenance’ (VLOM) has been used for a number of years in the hand-pumping community, with various definitions and
different descriptions as to when it can be considered to have been achieved. To some extent, the suggestion that something can be maintained at village level is wholly contained within Dunn’s definition of appropriate technology, as described above. However, by considering its application in a little more detail, it is possible to add to Dunn’s solution criteria through consideration of VLOM project examples. Tyndale-Briscoe and McMurdie suggest that VLOM for a pump (and consequently for the pump’s sustainability) relies on ‘(a) ease of use and maintenance, (b) durability (including corrosion resistance) and (c) the cost and availability of spare parts’ (Tyndale-Briscoe and McMurdie, 2000). These compliment Dunn’s criteria, introducing durability as a requirement, and specifically mentioning maintenance. Tyndale-Briscoe and McMurdie go on to describe the ‘Oxfam Pump’—a pump that they believe satisfies their VLOM criteria. Wood, however, questions whether such a VLOM solution is possible for mechanical pumps at all. He bases his argument on a discussion of two types of handpump—the Afridev and the India Mark II—suggesting that maintenance at village level is unachievable in Africa. His reasoning for the India Mark II is that ‘there are not the village level mechanics available that are commonly found in rural areas of India, where the popularity of the ubiquitous bicycle has encouraged a culture of village bicycle repair shops whose mechanics are ideally suited to repair handpumps, a technology on a par with that of bicycles’ (Wood, 1994). He goes on to say that ‘as the bicycle makes inroads into the African countryside we can expect an upsurge in the repair business which will auger well for the continued sustainability of handpumps’. This suggests two important principles. Firstly, that VLOM is highly dependent on location—the definition of ‘village level’ in one country, or even one region of a country, may well be different from the definition in a neighbouring area, due to a difference in skill availability. Secondly, it also suggests that as time goes on (and the village bicycle mechanic branches out to include, for example, motorbike or moped repair), increasing levels of pumping complexity may be acceptable and that more complicated pumps, such as PVPs, may well come under the ‘VLOM’ heading. Both principles lead to the conclusion that, prior to the installation of a PVP, consideration must be given as to whether the PVP can be maintained at the village level. If maintenance is not possible, consideration as to what could be maintained may well imply a more appropriate pumping solution in the immediate future, with potential to ‘upgrade’ to a PVP at a later date when technical skills in the area have improved. Such a gradual change is less likely to disrupt the village social structure, will allow easier understanding of the new technology by more people, and hence will permit adaptation of the technology to fit in better with local needs (Hazeltine and Bull, 1999). Combining the VLOM idea with the aims of ‘appro-
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priate technology’, it would seem likely that the ideal PVP solution is a pump that can be manufactured at villagelevel. This would therefore use ‘local skills’ and ‘local material resources’ and may therefore have the most beneficial and sustainable effects for the village. It would also fit in with Jespersen’s ‘basic requirement’ that users have ‘confidence in their own abilities to manage VLOM in respect to organisation, finance and technical aspects’ (Jespersen, 1995). At first glance it seems unlikely that a commercial pump manufacturer would consider such a proposition, as selling a single pump may lead to a complete removal of the market when the local communities realise that they can manufacture the pumps more cheaply. However, it has been shown to be possible by Bombas de Mecate S.A., a Nicaraguan company that manufactures ‘rope-and-washer’ pumps (see www.ropepump.com for details). Despite the simplicity, maintainability and rapid spread of this pump, Bombas de Mecate currently produces over 60% of the rope pumps sold in Nicaragua each year (based on 2000 figures). Indeed, this technology has been so successful that the company has a ‘Technology Transfer Division’ to pass on the skills and technology that is necessary to build and maintain this excellent example of a VLOM pump.
of site study, for water at any depth, irrespective of the amount of pipework required and usable in both boreholes and hand-dug wells. However, neither type of pump, as currently designed, could be manufactured at village level. Complex electrical systems and high-tolerance mechanical components are typical of commercial pumps and are consequently beyond the means and skills of local technicians. A further problem with many pumps currently on the market is their lack of reliability. Whilst this will not be considered in detail within this paper, it is a major problem, particularly for motors running off AC power, and consequently requiring an inverter. Many of the reliability problems are down to lack of consideration of the location of the inverters—for example, failing to provide lightning protection, or lack of proper glands around cables, allowing ingress of water or insects. Issues such as these are not fundamental errors that would themselves prevent solar powered pumps from reaching the ‘appropriate technology’ goal. They are simply a result of bad design. In general, therefore, it can be said that current technology is outside the realms of what could be considered to be VLOM, and consequently they cannot be described as ‘appropriate technology’.
4. Current technology
5. Social issues
There are two main types of motorised pumping device for PVPs: • centrifugal—where the high speed rotation of an impeller sucks water in through the middle of the pump and ‘throws’ water out at the edge; • positive displacement—where discrete ‘packets’ of water are transferred by a primary mover. This may be, for example, a piston, or a screw-type device. Due to the cost of PV panels, the lowest capital cost solution is usually sought, irrespective of reliability, longterm costs or efficiency. Whilst this typically leads to the use of centrifugal pumps in the PVP system, some current thinking suggests that positive displacement pumps—particularly piston pumps making use of the induced flow principle (Burton and Short, 1999)—may be more appropriate. The operating efficiency and output of a centrifugal pump is very much site-specific and its performance drops off rapidly away from design conditions. Such a departure from ‘design conditions’ may be as simple as the addition of extra pipework. A well-designed induced flow reciprocating (piston) pump, however, is able to pump over a wide range of heads without significant flow penalty at higher heads. This type of pump, if designed to fit within a standard 4 inch / 100 mm borehole could come close to reaching the ‘standardisation’ requirements often suggested as being a requirement for VLOM. The same pump could then be used, requiring neither modification nor any kind
A number of issues, both positive and negative, exist in a PVP project due to the involvement—or non-involvement—of people. Whilst the direct applicability of some of these issues to the design of the PVP system may not be immediately apparent, it is the authors’ view that they must all be borne in mind throughout the whole design, manufacture, installation and implementation process. Failure to acknowledge them is a failure to take into account the real needs of the customer and is likely to lead to unsustainability of the pumping system. A few of the issues will now be considered.
5.1. Ownership Failure of a community to take on ‘ownership’ of the PVP can often result in lack of even the most basic maintenance. Kaunmuang et al. (2001) describe such a situation where the ‘lack of responsibility [and] village commitment’ has led to pump failure in over 60% of the pumps surveyed. Clearly community ownership is extremely important. In a similar vein, Bannister (2000) requires that ‘the recipient community is in full support of a project’ if a project is to be sustainable. It should be noted that in this context, ‘ownership’ defines a sense of ownership rather than necessarily defining the actual possession of the borehole / pumping system. Verani (2000), for example, shows the approach
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taken by Enersol, an NGO operating in Latin America. Pump systems are owned and maintained by the supplier— Enersol—but the idea of community ‘ownership’ ensures that the villagers pay for the water supply. Without full community support, any benefits that the new water source supplies may rapidly be overcome by the negative issues. Ownership is not, however, sufficient on its own to ensure sustainability.
5.2. Theft /vandalism Simply because a community takes on ‘ownership’ of a PVP does not prevent theft of the system components such as the PV panels or any batteries. The issue can go considerably deeper into social relationships and rarely have a simple answer. PV panels are often seen as high value items and can be used for financial gain through use—as a battery charger for example. The six South African pumping locations described by Bannister (2000) required security fencing of some kind, some with electrified fences and motion detectors. The social situation can also play a part—for example, a PV panel could be ‘appropriated’ by a headman who views his need for a television to be greater than the villagers’ need for water. In this situation, the respect that headmen are afforded is likely to make villagers return to the old water source, rather than try to return the panel to the pumping system. One way of preventing such an occurrence is suggested by van Beers (2001). He proposes that system ownership by a private individual or organisation is the only way to ensure safety of the panels and pumping system. This individual would then require payment for the water. It would seem that this kind of ‘capitalist’ approach to PVPs has its proponents and, in this context at least, its benefits.
5.3. Community The societal importance attached to water in rural areas is shown by Macmillan through the description of a village in Burkina Faso. Young men in Silmiougou, a village in central Burkina Faso, would like a fair chance at finding wives in nearby villages. But they have a big handicap that is unrelated to their own suitability as husbands: their village has only one handpump for 3000 people. This fact makes women from outside Silmiougou dread the idea of marrying a man from there. They know their lives would be filled with the daily drudgery of spending hours fetching enough water to meet their family’s needs. So Silmiougou men end up marrying from within the village or leaving altogether (MacMillan, 2001). Thus, prior to installation, the impact that the provision of a water supply can have on neighbouring communities must be considered. Equally, the impact of the new water
source on the community itself must be considered. For example, where the water fetching and carrying has become something of a daily ‘social event’, the resulting community feeling may be somewhat removed by the absence of the walk due to a new and closer water source. In some circumstances, new water sources have caused deep community rifts, where those who previously carried and provided water for a fee (such as donkey owners) suddenly lost their livelihoods (Dunn, 1978) leading to vandalism of the new source and social discontent. In this case, simple consideration of the problem—which could have been carried out prior to the commissioning of the project—brought about the solution where these people were given jobs as pump caretakers. Even if such impacts are anticipated, ‘inappropriate’ siting of the pump can lead to social-mismatch of water to need. Kaunmuang et al. (2001) describe the locating of a PVP within the village headman’s compound, which caused villagers to believe that the pumps were not for their benefit. Should the pump be located more tactfully than in this case, social and ethnic status can still easily lead to conflicts at the water pump as one person or group of people deems themselves more in need of water than the other (MacMillan, 2001). This may again suggest that privatisation could be beneficial in that the same condition (payment for water) applies to all, irrespective of status. In contrast to the problems suggested above, a well planned and maintained PVP installation can increase social cohesion and improve the confidence and well-being of lower caste people (WaterAid, 2001). Migration away from villages can be reduced, as the new supply of water both makes village life less harsh and creates jobs in maintaining water supply and managing demand. The increased availability of time can also allow more community interaction in important social events such as marriages and funerals (WaterAid, 2001).
5.4. Institutional The attempt to apply a new technology to many ‘nonWestern’ societies, developing countries among them, can be met with a number of political and institutional issues. Many of these—such as what may be called ‘bribery’—are not viewed in the same light in Western countries and cannot be ignored if sustainability of any technology, whatever that technology may be, is to be attained. Failure to acknowledge the issues may result in active measures to prevent the technology being used, operating successfully and being shared. Thus, again, the involvement of people who know the workings of the local system is desperately important. An agency choosing to ignore such matters risks the wasting of the pumping systems due to what could be described as Western, inappropriate ideology. Whether or not the ideology is a moral issue is open to debate—what is not up for debate is the consequence of ignoring political and institutional customs.
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5.5. Gender Gender and water are inextricably linked in many developing countries—that this fact is not always fully appreciated demonstrates the misunderstanding that sometimes exists between aid agency and pump user. The link between water and gender ensures that the introduction of any new water source to a community can have considerable gender implications. The technology inherent in PVPs can only accentuate these implications. Thus the impact of PVPs on gender issues in the local community must be carefully considered and investigated on a case by case basis. An example of the gender-specific problems associated with the absence of a close supply of water comes from Bangladesh, where ‘difficulty during pregnancy and deformity in posture’ are reported simply due to the ‘carrying of traditional water pitchers on the hip’ (Sultana and Crow, 2000). On the other hand, the presence of a communal and nearby water supply can reduce the threat of ‘physical abuse and sexual harassment from well owners’ (WaterAid, 2001). Further gender benefits can be found in the improved health and safety of women during childbirth because of an adequate water supply—this same water supply also allowing improvements to women’s ‘personal hygiene, especially during their menstrual period . . . as they were able to bathe regularly’ (WaterAid, 2001). On a practical level, maintenance and repair training is often directed at men, even though water-related activities may well be carried out by women. This can result in a lack of maintenance and increased requirement for repair. In addition, should this repair not prove possible for an extended period of time, the load of satisfying the increased demand for water (stimulated by the presence of the PVP), is likely to fall squarely on the shoulders of women. Green and Baden have described this very situation in the village of Kataba, Senegal. The advent of a handpumping scheme meant that ‘gardens [were] extended in anticipation of improved water supplies’ (Green and Baden, 1994)—when the new pumps broke down therefore, the women were ‘forced to use the old technology, but to a greater extent’. Whilst it may be assumed that successful provision of water close to a village may ease the burden on women, that is not always the case. Removing the trek to a distant water source may increase time available for women but that time may equally be used for extra domestic work (Madau, 1998). Some reports have shown that the burden on women can in fact be considerably increased by an improved water supply, particularly where the extra water is used for irrigation and thus more work is needed tending crops (Chancellor, 2000). Others, however, have shown the extra time to be used for education (WaterAid, 2001)— it cannot be stressed enough how important this can be, for addressing poverty directly and for improving the life choices of women. According to research published by the
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UK Department for International Development (DfID) ‘education for girls is the single most effective way of reducing poverty’ (Smout and Coates, 2000). Thus the presence of any water source, (including PVPs) in a community can indirectly address poverty through directly addressing gender relations. The role that gender plays in a community can sometimes become less well defined, by the addition of a closer water source. Madau reports on a shift in gender roles in Zimbabwe: ‘Since [water] is collected from a tap, it is easily accessible and even prestigious, hence even males were happy to be associated with water fetching’ (Madau, 1998). The converse is also true in India, where it has been reported that ‘women . . . took over roles traditionally assigned to men, such as the operation and maintenance of handpumps’ (WaterAid, 2001).
5.6. Health One of the unarguable benefits that the addition of a safe water supply brings is that of health. Worldwide, 25,000 people die every day due to unsafe water (International Institute for Environment and Development, 2000). In contrast, the addition of boreholes to sites in Nigeria is reported to have reduced ‘important’ illnesses by around 50% (Nogier, 1998). However, there can still be health issues if the PVP system and borehole are not designed and maintained suitably. If a safe water output is to be sustained a number of factors need consideration, including: good borehole design and siting; good design of the surroundings at the borehole and reservoir outlets; and, again, good maintenance of all parts of the system including the borehole. Failure to correctly oversee the watering station can result in unhygienic practices, which may include contamination from livestock (MacMillan, 2001), development of stagnant pools—a breeding ground for disease-carrying insects—and similar problems. Issues such as these are predominantly down to good social management and community involvement, along with health education, rather than technological solutions. The consequences on health of the failure of a PVP system can be quite extreme. Whilst large numbers of toxins may be present in traditional water sources, the users can build up immunity over a period of time. When a new pump system is implemented, lack of exposure to the toxins may lead to weakening or loss of this immunity. Should the users then revert to the old water source, because of pump failure for example, they will therefore succumb to what could now be life-threatening illnesses (Hazeltine and Bull, 1999). Clearly therefore, not only should the PVP be designed to be reliable, it should also be designed for the minimum down-time when repair is required and this requires that the pump be designed within the appropriate technology / VLOM principles.
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5.7. Economic The increase in health has far-reaching effects, including increased economic prosperity as more water and / or more time is available for commercial activities. The local economy can further reap significant benefits from the presence of a technician skilled in PVP installation and maintenance, whilst the extra time made available for women and children can be used for furthering education. PV pumping can be seen as one of a number of steps along the development route and, if well planned and executed through local management committees, allows the local communities to determine this route for themselves. Whether PVPs should be considered to be a first step towards development or a second step after prior introduction of a hand-powered pump, for example, is a question which will not be debated here. There are, however, negative economic aspects, particularly where the purchase of the PVP system is concerned. There is no doubt that PV pumping systems carry a high capital cost, a considerable portion of which is due to the cost of the photovoltaics. Current costs seem likely to preclude those who most need the water unless external organisations, such as governments, aid agencies, or NGOs, become involved. These prohibitive costs, however, are gradually being recognised as ‘offset over time by the minimal running costs’ (Faulkner and Lenehan, 1997). The financial viability of PVPs against hand pumps or diesel generators has been widely considered and results in considerable potential. Faulkner and Lenehan identify the limits of feasibility for PVPs, based on the cost of providing a certain power output from the PV array. Even with these limits they are able to identify 4000 communities in the KwaZulu Natal area of South Africa alone where PVPs are a ‘viable option’. Indeed, they conclude that ‘despite problems of cost and present unfamiliarity, PVP . . . use is likely to increase in the future’ (Faulkner and Lenehan, 1997). The economic viability of PVPs varies both within and between countries and must be known by those seeking to implement them. In addition, the availability of credit and / or aid will play a significant part. Posorski and Haars (1994), for example, considered seven countries over three continents. Whereas they suggested viability in Argentina for all sizes of PVP under 4 kWp with normal credit terms, in Indonesia even special credit conditions could not enable PVPs to compete with other sources. A comparison of the costs of PV, wind and diesel pumping in two areas of Jordan showed PV and wind (mechanical) pumping to be economic against diesel pumps (Hammad, 1995). In a somewhat more up to date consideration of water pumping in India it was difficult to find any conditions—including capital subsidy—under which PVPs could compete successfully with other options, such as diesel or wind
powered pumps (Rubab and Kandpal, 1998). Bannister (2000), however, shows that a 1 kW PVP system in South Africa becomes more economical than a diesel system after just 3 years of operation. Clearly local costs need consideration before proceeding with the design and purchase of a PVP system. Once a system has been purchased and installed, the question of payment for the output water is very difficult, again varying within and between countries. In particular, consideration must be given to who is paying, what the money they are paying goes towards (running costs, recovery of capital cost, maintenance costs or even setting money aside for future replacement), whether the amount required is affordable and, perhaps most importantly, are the people willing to pay for water? Whilst the last point may prove the most contentious—particularly when water can be considered a ‘Fundamental Human Right’ within the bounds of the UN Universal Declaration of Human Rights 1 —many organisations are clearly of the opinion that people will pay for the provision of clean water and that only by doing so will the system be sustainable. Where a community is required to provide some kind of finance for a project it would seem likely that they will ensure that it is appropriately maintained. The failure of pumps, described by Kaunmuang et al. (2001) (see Section 5.1) is primarily put down to a failure of promoting agencies to install a ‘mechanism for water management, including fee collection’ which would in turn have brought about the ¨ community ‘ownership’. On the other hand, Munger (2000) quotes an ‘excellent bill collection rate’ as an indication of user satisfaction (and hence system sustainability) in Mauritania, whilst Enersol Associates clearly aims to ensure recovery of all the costs of installed systems—even to the extent that it ‘maintains the right to remove the PV equipment if . . . [the] community defaults on payments’ (Verani, 2000; Johnson, 2001). The issue then becomes providing an adequate financial mechanism that will allow appropriate credit terms and repayments as per the community’s means and water usage. However, some people are liable to use more water than others, suggesting either some form of metering or water management, or sufficient community ‘spirit’ to allow this without causing conflict. There is a very strong gender aspect to the economy of PVPs due to all property and finances being entirely under the control and ownership of men in many developing countries. Whilst this will not be further considered here, it is clearly a particularly important factor that must be taken into account throughout the system installation and implementation.
1 See Blackman (1999) for a full discussion of the ‘right’ to water and the financing of water supplies.
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5.8. Summary Every project has its own situation, and that situation is defined by the social, economic and technological capabilities of the people involved. None of the individual issues outlined above can therefore exist in isolation—they are all interlinked, with the common feature being that they all impinge directly on the sustainability or otherwise of the PVP system. For example, payment for water seems likely to lead to community ‘ownership’ of the pump. Some sort of mechanism for this payment must therefore be set up, and this mechanism must be appropriate to the institutional and community needs. A single breakdown in one of these areas can prevent sustainability in all areas. The concerns outlined above cannot be assumed to be a fully comprehensive list. For example, one issue not addressed is the potential for population explosion due to the increased health and the attraction to neighbouring villagers. Nor has the need for follow-up from the suppliers been considered. What has been shown is that the application of PVPs is extremely complex, that people have already addressed many of the problems in given situations and that these lessons have rarely been passed on. The PVP system design must therefore bear in mind any number of ideas, ideologies and concerns—failure to do so on a site-specific basis is liable to lead to unsustainability. However, many of these concerns can at least be considered at the design stage and it is this that will now be investigated.
6. Breaking the mould In designing a pump that is to ‘break the mould’—to make use of appropriate technology, and be maintainable at village level—all of the above discussion must be recognised. This incorporates both technological and sociological factors, and whilst the socio-economic arguments may not all seem directly relevant to the design process, it is important not to dismiss them out of hand. For example, one might ask ‘how can a pump be designed to ensure community ownership?’. The answer ‘by ensuring that it is appropriate to the community’ introduces the complex inter-relationship of all the issues. It may prove necessary to consider gender aspects (in maintenance and use), economic aspects (in the payment for the pump), social and health aspects (in its installation) and so on. To produce a well-designed pump, all of these must therefore be borne in mind. The pump under consideration and testing at the University of Durham has been designed within this context and within Dunn’s requirements for ‘appropriate technology’. One of the major considerations was therefore to create a ‘one pump fits all situations’ design, in order to
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allow village-manufactured pumps to be applicable irrespective of site-specific details and at minimum cost. In order to satisfy this, the pump is based on induced flow principles and therefore has a reciprocating piston to drive the water flow. Traditionally, reciprocating pumps are driven from the motor using some kind of cam arrangement, to convert the rotational output of the motor into linear motion at the piston. Should the pump be above ground, various mechanical means can be used for the conversion. Below ground, the situation is more difficult, particularly if the design is aimed at boreholes where the borehole diameter (typically 100 or 150 mm) provides great restriction on the size of the pump components. Nevertheless, some pumps, such as the Fluxinos ‘SOLAFLUX’ or the Divwatt ‘SOLASTAR’ have been able to accomplish this, at the expense of frictional energy loss between a cam shaft and cam. An alternative to a traditional motor is to consider a device that will take electrical energy and convert it directly to linear movement—in the case of providing motive power to a piston, this seems far more sensible than the use of a rotational motor. A number of possibilities in the linear domain exist and have had some, though limited, investigation in the past. Perris and Salameh (1995), for example, describe a surface mounted pump using a linear drive. However, little has been considered for the downborehole situation suggested here, predominantly because of the size restrictions. There are two design solutions currently under investigation at the Durham Centre for Renewable Energy, both running off DC electricity, to remove the necessity for complex (and potentially unreliable) electronics. The first uses an electromagnet to pull (or push, depending on the configuration) an armature attached to a diaphragm. The second option is to use a linear motor directly coupled to a piston / diaphragm arrangement. The two systems are very different in characteristics, for example operating frequency, piston stroke and so on, but share in the potential for VLOM and appropriate technology. For example, it is widely held in the hand-pumping community that PVC pipes are readily available and this can be incorporated into the design of the pump body. Whilst the electromagnetic and linear motor may not be manufactured in developing countries easily, they require no maintenance, have no moving parts in themselves and would not be expected to fail under any realistic circumstances. How does this pump, then, fit in with Dunn’s aims and objectives? 1. Employ local skills. Manufacture—and consequently maintenance—of most parts of the pump presents no problems using local skills. Indeed, some level of direct employment will be provided, in addition to the pump manufacture, by the requirement for a local mechanic to carry out the maintenance and repair. There is also likely to be employment in managing the water supply,
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ensuring the hygiene of the water distribution point and, perhaps, collecting any payment. 2. Employ local material resources. The manufacture of pumps and spare parts using local material resources is certainly possible throughout much of the developing world and the potential exists for a local entrepreneur to set up a business with the majority of the pump manufactured and assembled locally, buying in solely the PV and electromagnetic components. 3. Employ local financial resources. The use of ‘local financial resources’ introduces the problem of the system capital cost. If this is borne through favourable credit terms, some financial system can be set up to pay what can be afforded. This will ensure that the credit is paid off, and long-term maintenance (and perhaps pump replacement) can also be paid for. Furthermore, through requiring some kind of payment for the pump, it seems likely that sustainability will become a real possibility. 4. Be compatible with local culture and practices. This is somewhat harder to deal with at the design stage. Certainly the system design can be made to allow for the possibility of requiring minimal physical strength, allowing both men and women, as appropriate, to carry out maintenance. During operation, however, there seems to be no reason for conflict between the PVP technology and local culture and practices. 5. Satisfy local wishes and needs. These are enshrined in the provision of water. As long as it is recognised that water is the need rather than PVPs, the sustainability of the system is likely to be ensured. By considering Dunn’s criteria at the design stage, therefore, it has proved entirely possible to produce a pump that meets the aims of both ‘appropriate technology’ and VLOM. Whilst the pumps are currently under study at prototype stage, it is anticipated that further reports will demonstrate their true potential to tackle the joint problems of water provision and sustainability in developing countries.
7. Summary and conclusions Appropriate technology and village level operation and maintenance are two design ideologies that, when considered together, can contribute towards the sustainability of solar powered water pumps. Both of these sets of principles, however, have implications beyond technology and into the socio-economic domain within which the technology must operate. Failure to consider these non-technological issues—by designers, manufacturers, suppliers and installers—can lead to situations where the technology becomes unsustainable, as has been demonstrated in many sites throughout the developing world. However, if both the technological and socio-economic situations are recognised, creating a ‘complete picture’ at the system design
stage, the aims of ‘appropriate technology’ and VLOM can be achieved, resulting in great potential for sustainability. Research at the Durham Centre for Renewable Energy has established the existence of design solutions through the use of a linear-electric drive, directly driven by the PV array and coupled to an induced flow pumping system. Should the continued pump testing programme demonstrate the performance that is promised, it seems likely that sustainable PV pumps will become a matter of fact, rather than a matter of luck.
Acknowledgements The authors would like to thank the Nuffield Foundation for supporting Mr. Thompson under the Undergraduate Research Bursary (NUF-URB01) scheme. Dr. Short would also like to acknowledge the support of EPSRC, grant ref. GR / R51537 / 01, in funding his travel to the ISES 2001 Solar World Congress.
References Bannister, M., 2000. Solar power for community water supply. In: Pickford, J. (Ed.), 26th WEDC Conference—Water, Sanitation and Hygiene: Challenges of the Millennium, Dhaka, Bangladesh, pp. 311–314. Blackman, R., 1999. Financing of Rural Water Supply Systems from a Rights Perspective: A Case Study of the Rope Pump in Nicaragua. International Development Department, School of Public Policy, University of Birmingham, Birmingham. Burton, J.D., Short, T.D., 1999. Induced flow reciprocating pumps part 2. Proc. Inst. Mech. Engrs., Part A, J. Power Energy 213 (A5), 375–389. Chancellor, F., 2000. Sustainable irrigation and the gender question in Southern Africa. In: Sustainable Development International: Strategies and Technologies for Agenda 21 Implementation, pp. 59–63. Dunn, P.D., 1978. Appropriate Technology. Macmillan Press. Faulkner, R., Lenehan, A., 1997. Options for rural water supply. In: Pickford, J. et al. (Ed.), 23rd WEDC Conference—Water and Sanitation for All: Partnerships and Innovations, Durban, South Africa, pp. 280–282. Green, C., Baden, S., 1994. Gender Issues in Water and Sanitation Projects in Senegal. Institute of Development Studies, University of Sussex. Hammad, M., 1995. Photovoltaic, wind and diesel: a cost comparative study of water pumping options in Jordan. Energy Policy 23 (8), 723–726. Hazeltine, B., Bull, C., 1999. Appropriate Technology. Academic Press, London. International Institute for Environment and Development, 2000. Drawers of Water II: Thirty Years of Change in Domestic Water Use and Environmental Health in East Africa, http: / / www.iied.org / agri / dowrv-intro.html. Access date January 2001, hardcopy on file with author.
T.D. Short, P. Thompson / Solar Energy 75 (2003) 1–9 Jespersen, C.B., 1995. Village level operation and maintenance. In: Pickford, J. et al. (Ed.), 21st WEDC Conference—Sustainability of Water and Sanitation Services, Kampala, Uganda, pp. 173– 175. Johnson, E., 2001. Long road to cost recovery in rural water supply. In: Sustainable Development International: Strategies and Technologies for Agenda 21 Implementation, pp. 65–69. Kaunmuang, P., Kirtikara, K. et al., 2001. Assessment of photovoltaic pumping systems in Thailand—one decade experience. Solar Energy Mater. Solar Cells 67 (1–4), 529–534. MacMillan, N., 2001. Burkina Faso: Managing Conflict at the Village Handpump and Beyond. International Development Research Centre: 4, Canada, Project no. 4391. Madau, S., 1998. Women and energy—investigating gender benefits in a PVP project in Zimbabwe. In: Renewable Energy for Development: Newsletter of the Energy, Environment & Development Programme. Stockholm Environment Institute, pp. 2–3. ¨ Munger, F., 2000. Mauritania—water solar system: a sustainable approach for villages and small towns. In: Village Power 2000, Washington, DC, USA. Nogier, A., 1998. Mise en Place d’un Schema de Pompage Photovoltaique au Nigeria. In: International Workshop on PV Water Supply Issues, Marrakech, pp. 73–77. Perris, C., Salameh, Z., 1995. Photovoltaic-powered piston-type water pump controlled by a linear motor. Prog. Photovoltaics: Res. Appl. 3, 265–271. Posorski, R., Haars, K., 1994. The Economics of Photovoltaic ¨ Technische Pumping Systems. Deutsch Gesellschaft Fur Zusammenarbeit (GTZ) GmbH, Eschborn.
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Rubab, S., Kandpal, T.C., 1998. A financial evaluation of renewable energy technologies for water pumping in rural areas. Int. J. Ambient Energy 19 (4), 211–220. Smout, I., Coates, S., 2000. Gender without jargon—approaches to engineers. In: Pickford, J. (Ed.), 26th WEDC Conference— Water, Sanitation and Hygiene: Challenges of the Millennium, Dhaka, Bangladesh, pp. 411–415. Sultana, F., Crow, B., 2000. Water concerns in rural Bangladesh: a gendered perspective. In: Pickford, J. (Ed.), 26th WEDC Conference—Water, Sanitation and Hygiene: Challenges of the Millennium, Dhaka, Bangladesh, pp. 416–419. Tyndale-Briscoe, P., McMurdie, D., 2000. A VLOM handpump for 80 metres. In: Pickford, J. (Ed.), 26th WEDC Conference— Water, Sanitation and Hygiene: Challenges of the Millennium, Dhaka, Bangladesh, pp. 49–52. van Beers, P., 2001. Sustainable Again?, ‘HTN’ e-mail Discussion List, http: / / www.jiscmail.ac.uk / lists / water-and-san-applied-research.html. Verani, A., 2000. Solar-powered clean water delivery in the Dominican Republic & Honduras. In: Village Power 2000, Washington, DC, USA. WaterAid, 2001. In: Blagborough, V. (Ed.), Looking Back: The Long-term Impacts of Water and Sanitation Projects. Wood, M., 1994. Are handpumps really affordable? In: Pickford, J. et al. (Ed.), 20th WEDC Conference—Affordable Water Supply and Sanitation, Colombo, Sri Lanka, pp. 132–134.
Breaking the mould: solar water pumping—the challenges and the reality q T.D. Short*, P. Thompson School of Engineering, University of Durham, South Road, Durham DH1 3 LE, UK Received 11 May 2002; accepted 30 June 2003
Abstract Solar (photovoltaic) powered water pumping has the potential to bring sustainable supplies of potable water to millions of people in developing countries. Unfortunately, in many cases the application of the pump technology ignores the sociological and economic needs of the users, leading to lack of maintenance, inappropriate financing schemes, inadequate system management and, ultimately, failure of the pump. This paper investigates some of the issues involved in solar water pumping projects, describes the positive and negative effects that they can have on the community and, in proposing an entirely new type of pump, considers what steps could be taken to ensure future sustainability. 2003 Elsevier Ltd. All rights reserved.
1. Introduction For many years, solar (photovoltaic) powered water pumps (PVPs) have been portrayed as the harbinger of a new era in water provision for rural and developing communities. Mass produced pumps and cheaper photovoltaic (PV) panels promised fresh potable water for everyone. Although inroads have been made to reaching this ideal situation, the current reality is somewhat different. There still remain considerable challenges in developing, distributing and applying ‘appropriate’ solar powered water pumps. Solar powered water pumps have the potential to provide significant changes to rural communities—not only through the direct provision of water, but also through the possibilities of sociological and economic development. The impact of PVPs can go beyond the availability of fresh water, but can have both positive and negative consequences. Without knowledge of these consequences it is difficult to see how PVP designers, manufacturers and project implementers can hope to provide a sustainable solution to the problem of water provision. q This paper was presented at the ISES 2001 Solar World Congress in Adelaide, Australia. *Corresponding author. Tel.: 144-191-334-2514; fax: 144191-334-2377. E-mail address: [email protected] (T.D. Short).
This paper will therefore investigate PVPs within the contextual background of ‘appropriate technology’, a design methodology that considers the reasons for technological development and its potential impact on a community. The ideas of ‘village level operation and maintenance’ (‘VLOM’) will be examined, and consideration will be given to how the arising concerns are—or are not—addressed by current designs and operational practices. The paper will then discuss the basic developmental issues that should underpin the design and application of PV powered water pumps and how projects have failed or succeeded because of these issues. Finally, it will consider the development of a novel pump system and how it is being designed in an attempt to ‘break the mould’ by wholly embracing the design philosophy of appropriate technology.
2. Appropriate technology Dr. E.F. Schumacher is quoted by Professor P.D. Dunn as saying ‘A project that does not fit, educationally and organizationally, into the environment, will be an economic failure and a cause of disruption’ (Dunn, 1978). Indeed, this has been seen to be the case in numerous projects throughout the world. In addressing this concern, Dunn uses the expression ‘appropriate technology’ to describe the use of technology in situations that are the
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opposite to those described by Schumacher. He summarises appropriate technology through the following. The principal aims of development are 1. To improve the quality of life of the people. 2. To maximise the use of renewable resources. 3. To create work places where the people now live. The solutions chosen should satisfy the following criteria 1. Employ local skills. 2. Employ local material resources. 3. Employ local financial resources. 4. Be compatible with local culture and practices. 5. Satisfy local wishes and needs. (Dunn, 1978) Thus a solution making use of appropriate technology must consider—and satisfy—each of the five criteria. Failure to address them is likely to lead to an unsustainable project. Considering Dunn’s criteria, it is clear that whilst the major need of those who are to use a solar pumping system is simply water, there are a number of further issues. Social, economic, health and gender concerns are all directly relevant and yet are often neglected in the design and application of a pumping system. In particular, however, Dunn points out that the solution must be ‘compatible with local cultures and practices’. This demands consideration as to what the local community wants from development as opposed to what aid agencies, for example, think the community want. The question as to whether or not ‘development’ (as understood by ‘more developed’ countries) is required or indeed desired is beyond the scope of this paper. The vast majority of PV pumping systems are developed in ‘Western’ countries where the main design consideration is the cost. In theory, by improving the efficiency of the pump system from PV output to water output (i.e. from ‘wire-to-water’), the number of solar panels required will be reduced and the total pump system will therefore be that much cheaper, broadening its appeal and customer base. Whilst the price of solar panels remains high, this seems a logical approach to furthering the applicability of solar water pumps. Unfortunately it is also a superficial approach, ignoring other factors of potentially greater influence than cost alone. In failing to fully understand the real requirements of, and consequent effects on, the end user, the idea of using ‘appropriate technology’ is largely ignored and solar water pumping remains purely a ‘good idea’.
3. ‘Village level operation and maintenance’ The expression ‘village level operation and maintenance’ (VLOM) has been used for a number of years in the hand-pumping community, with various definitions and
different descriptions as to when it can be considered to have been achieved. To some extent, the suggestion that something can be maintained at village level is wholly contained within Dunn’s definition of appropriate technology, as described above. However, by considering its application in a little more detail, it is possible to add to Dunn’s solution criteria through consideration of VLOM project examples. Tyndale-Briscoe and McMurdie suggest that VLOM for a pump (and consequently for the pump’s sustainability) relies on ‘(a) ease of use and maintenance, (b) durability (including corrosion resistance) and (c) the cost and availability of spare parts’ (Tyndale-Briscoe and McMurdie, 2000). These compliment Dunn’s criteria, introducing durability as a requirement, and specifically mentioning maintenance. Tyndale-Briscoe and McMurdie go on to describe the ‘Oxfam Pump’—a pump that they believe satisfies their VLOM criteria. Wood, however, questions whether such a VLOM solution is possible for mechanical pumps at all. He bases his argument on a discussion of two types of handpump—the Afridev and the India Mark II—suggesting that maintenance at village level is unachievable in Africa. His reasoning for the India Mark II is that ‘there are not the village level mechanics available that are commonly found in rural areas of India, where the popularity of the ubiquitous bicycle has encouraged a culture of village bicycle repair shops whose mechanics are ideally suited to repair handpumps, a technology on a par with that of bicycles’ (Wood, 1994). He goes on to say that ‘as the bicycle makes inroads into the African countryside we can expect an upsurge in the repair business which will auger well for the continued sustainability of handpumps’. This suggests two important principles. Firstly, that VLOM is highly dependent on location—the definition of ‘village level’ in one country, or even one region of a country, may well be different from the definition in a neighbouring area, due to a difference in skill availability. Secondly, it also suggests that as time goes on (and the village bicycle mechanic branches out to include, for example, motorbike or moped repair), increasing levels of pumping complexity may be acceptable and that more complicated pumps, such as PVPs, may well come under the ‘VLOM’ heading. Both principles lead to the conclusion that, prior to the installation of a PVP, consideration must be given as to whether the PVP can be maintained at the village level. If maintenance is not possible, consideration as to what could be maintained may well imply a more appropriate pumping solution in the immediate future, with potential to ‘upgrade’ to a PVP at a later date when technical skills in the area have improved. Such a gradual change is less likely to disrupt the village social structure, will allow easier understanding of the new technology by more people, and hence will permit adaptation of the technology to fit in better with local needs (Hazeltine and Bull, 1999). Combining the VLOM idea with the aims of ‘appro-
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priate technology’, it would seem likely that the ideal PVP solution is a pump that can be manufactured at villagelevel. This would therefore use ‘local skills’ and ‘local material resources’ and may therefore have the most beneficial and sustainable effects for the village. It would also fit in with Jespersen’s ‘basic requirement’ that users have ‘confidence in their own abilities to manage VLOM in respect to organisation, finance and technical aspects’ (Jespersen, 1995). At first glance it seems unlikely that a commercial pump manufacturer would consider such a proposition, as selling a single pump may lead to a complete removal of the market when the local communities realise that they can manufacture the pumps more cheaply. However, it has been shown to be possible by Bombas de Mecate S.A., a Nicaraguan company that manufactures ‘rope-and-washer’ pumps (see www.ropepump.com for details). Despite the simplicity, maintainability and rapid spread of this pump, Bombas de Mecate currently produces over 60% of the rope pumps sold in Nicaragua each year (based on 2000 figures). Indeed, this technology has been so successful that the company has a ‘Technology Transfer Division’ to pass on the skills and technology that is necessary to build and maintain this excellent example of a VLOM pump.
of site study, for water at any depth, irrespective of the amount of pipework required and usable in both boreholes and hand-dug wells. However, neither type of pump, as currently designed, could be manufactured at village level. Complex electrical systems and high-tolerance mechanical components are typical of commercial pumps and are consequently beyond the means and skills of local technicians. A further problem with many pumps currently on the market is their lack of reliability. Whilst this will not be considered in detail within this paper, it is a major problem, particularly for motors running off AC power, and consequently requiring an inverter. Many of the reliability problems are down to lack of consideration of the location of the inverters—for example, failing to provide lightning protection, or lack of proper glands around cables, allowing ingress of water or insects. Issues such as these are not fundamental errors that would themselves prevent solar powered pumps from reaching the ‘appropriate technology’ goal. They are simply a result of bad design. In general, therefore, it can be said that current technology is outside the realms of what could be considered to be VLOM, and consequently they cannot be described as ‘appropriate technology’.
4. Current technology
5. Social issues
There are two main types of motorised pumping device for PVPs: • centrifugal—where the high speed rotation of an impeller sucks water in through the middle of the pump and ‘throws’ water out at the edge; • positive displacement—where discrete ‘packets’ of water are transferred by a primary mover. This may be, for example, a piston, or a screw-type device. Due to the cost of PV panels, the lowest capital cost solution is usually sought, irrespective of reliability, longterm costs or efficiency. Whilst this typically leads to the use of centrifugal pumps in the PVP system, some current thinking suggests that positive displacement pumps—particularly piston pumps making use of the induced flow principle (Burton and Short, 1999)—may be more appropriate. The operating efficiency and output of a centrifugal pump is very much site-specific and its performance drops off rapidly away from design conditions. Such a departure from ‘design conditions’ may be as simple as the addition of extra pipework. A well-designed induced flow reciprocating (piston) pump, however, is able to pump over a wide range of heads without significant flow penalty at higher heads. This type of pump, if designed to fit within a standard 4 inch / 100 mm borehole could come close to reaching the ‘standardisation’ requirements often suggested as being a requirement for VLOM. The same pump could then be used, requiring neither modification nor any kind
A number of issues, both positive and negative, exist in a PVP project due to the involvement—or non-involvement—of people. Whilst the direct applicability of some of these issues to the design of the PVP system may not be immediately apparent, it is the authors’ view that they must all be borne in mind throughout the whole design, manufacture, installation and implementation process. Failure to acknowledge them is a failure to take into account the real needs of the customer and is likely to lead to unsustainability of the pumping system. A few of the issues will now be considered.
5.1. Ownership Failure of a community to take on ‘ownership’ of the PVP can often result in lack of even the most basic maintenance. Kaunmuang et al. (2001) describe such a situation where the ‘lack of responsibility [and] village commitment’ has led to pump failure in over 60% of the pumps surveyed. Clearly community ownership is extremely important. In a similar vein, Bannister (2000) requires that ‘the recipient community is in full support of a project’ if a project is to be sustainable. It should be noted that in this context, ‘ownership’ defines a sense of ownership rather than necessarily defining the actual possession of the borehole / pumping system. Verani (2000), for example, shows the approach
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taken by Enersol, an NGO operating in Latin America. Pump systems are owned and maintained by the supplier— Enersol—but the idea of community ‘ownership’ ensures that the villagers pay for the water supply. Without full community support, any benefits that the new water source supplies may rapidly be overcome by the negative issues. Ownership is not, however, sufficient on its own to ensure sustainability.
5.2. Theft /vandalism Simply because a community takes on ‘ownership’ of a PVP does not prevent theft of the system components such as the PV panels or any batteries. The issue can go considerably deeper into social relationships and rarely have a simple answer. PV panels are often seen as high value items and can be used for financial gain through use—as a battery charger for example. The six South African pumping locations described by Bannister (2000) required security fencing of some kind, some with electrified fences and motion detectors. The social situation can also play a part—for example, a PV panel could be ‘appropriated’ by a headman who views his need for a television to be greater than the villagers’ need for water. In this situation, the respect that headmen are afforded is likely to make villagers return to the old water source, rather than try to return the panel to the pumping system. One way of preventing such an occurrence is suggested by van Beers (2001). He proposes that system ownership by a private individual or organisation is the only way to ensure safety of the panels and pumping system. This individual would then require payment for the water. It would seem that this kind of ‘capitalist’ approach to PVPs has its proponents and, in this context at least, its benefits.
5.3. Community The societal importance attached to water in rural areas is shown by Macmillan through the description of a village in Burkina Faso. Young men in Silmiougou, a village in central Burkina Faso, would like a fair chance at finding wives in nearby villages. But they have a big handicap that is unrelated to their own suitability as husbands: their village has only one handpump for 3000 people. This fact makes women from outside Silmiougou dread the idea of marrying a man from there. They know their lives would be filled with the daily drudgery of spending hours fetching enough water to meet their family’s needs. So Silmiougou men end up marrying from within the village or leaving altogether (MacMillan, 2001). Thus, prior to installation, the impact that the provision of a water supply can have on neighbouring communities must be considered. Equally, the impact of the new water
source on the community itself must be considered. For example, where the water fetching and carrying has become something of a daily ‘social event’, the resulting community feeling may be somewhat removed by the absence of the walk due to a new and closer water source. In some circumstances, new water sources have caused deep community rifts, where those who previously carried and provided water for a fee (such as donkey owners) suddenly lost their livelihoods (Dunn, 1978) leading to vandalism of the new source and social discontent. In this case, simple consideration of the problem—which could have been carried out prior to the commissioning of the project—brought about the solution where these people were given jobs as pump caretakers. Even if such impacts are anticipated, ‘inappropriate’ siting of the pump can lead to social-mismatch of water to need. Kaunmuang et al. (2001) describe the locating of a PVP within the village headman’s compound, which caused villagers to believe that the pumps were not for their benefit. Should the pump be located more tactfully than in this case, social and ethnic status can still easily lead to conflicts at the water pump as one person or group of people deems themselves more in need of water than the other (MacMillan, 2001). This may again suggest that privatisation could be beneficial in that the same condition (payment for water) applies to all, irrespective of status. In contrast to the problems suggested above, a well planned and maintained PVP installation can increase social cohesion and improve the confidence and well-being of lower caste people (WaterAid, 2001). Migration away from villages can be reduced, as the new supply of water both makes village life less harsh and creates jobs in maintaining water supply and managing demand. The increased availability of time can also allow more community interaction in important social events such as marriages and funerals (WaterAid, 2001).
5.4. Institutional The attempt to apply a new technology to many ‘nonWestern’ societies, developing countries among them, can be met with a number of political and institutional issues. Many of these—such as what may be called ‘bribery’—are not viewed in the same light in Western countries and cannot be ignored if sustainability of any technology, whatever that technology may be, is to be attained. Failure to acknowledge the issues may result in active measures to prevent the technology being used, operating successfully and being shared. Thus, again, the involvement of people who know the workings of the local system is desperately important. An agency choosing to ignore such matters risks the wasting of the pumping systems due to what could be described as Western, inappropriate ideology. Whether or not the ideology is a moral issue is open to debate—what is not up for debate is the consequence of ignoring political and institutional customs.
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5.5. Gender Gender and water are inextricably linked in many developing countries—that this fact is not always fully appreciated demonstrates the misunderstanding that sometimes exists between aid agency and pump user. The link between water and gender ensures that the introduction of any new water source to a community can have considerable gender implications. The technology inherent in PVPs can only accentuate these implications. Thus the impact of PVPs on gender issues in the local community must be carefully considered and investigated on a case by case basis. An example of the gender-specific problems associated with the absence of a close supply of water comes from Bangladesh, where ‘difficulty during pregnancy and deformity in posture’ are reported simply due to the ‘carrying of traditional water pitchers on the hip’ (Sultana and Crow, 2000). On the other hand, the presence of a communal and nearby water supply can reduce the threat of ‘physical abuse and sexual harassment from well owners’ (WaterAid, 2001). Further gender benefits can be found in the improved health and safety of women during childbirth because of an adequate water supply—this same water supply also allowing improvements to women’s ‘personal hygiene, especially during their menstrual period . . . as they were able to bathe regularly’ (WaterAid, 2001). On a practical level, maintenance and repair training is often directed at men, even though water-related activities may well be carried out by women. This can result in a lack of maintenance and increased requirement for repair. In addition, should this repair not prove possible for an extended period of time, the load of satisfying the increased demand for water (stimulated by the presence of the PVP), is likely to fall squarely on the shoulders of women. Green and Baden have described this very situation in the village of Kataba, Senegal. The advent of a handpumping scheme meant that ‘gardens [were] extended in anticipation of improved water supplies’ (Green and Baden, 1994)—when the new pumps broke down therefore, the women were ‘forced to use the old technology, but to a greater extent’. Whilst it may be assumed that successful provision of water close to a village may ease the burden on women, that is not always the case. Removing the trek to a distant water source may increase time available for women but that time may equally be used for extra domestic work (Madau, 1998). Some reports have shown that the burden on women can in fact be considerably increased by an improved water supply, particularly where the extra water is used for irrigation and thus more work is needed tending crops (Chancellor, 2000). Others, however, have shown the extra time to be used for education (WaterAid, 2001)— it cannot be stressed enough how important this can be, for addressing poverty directly and for improving the life choices of women. According to research published by the
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UK Department for International Development (DfID) ‘education for girls is the single most effective way of reducing poverty’ (Smout and Coates, 2000). Thus the presence of any water source, (including PVPs) in a community can indirectly address poverty through directly addressing gender relations. The role that gender plays in a community can sometimes become less well defined, by the addition of a closer water source. Madau reports on a shift in gender roles in Zimbabwe: ‘Since [water] is collected from a tap, it is easily accessible and even prestigious, hence even males were happy to be associated with water fetching’ (Madau, 1998). The converse is also true in India, where it has been reported that ‘women . . . took over roles traditionally assigned to men, such as the operation and maintenance of handpumps’ (WaterAid, 2001).
5.6. Health One of the unarguable benefits that the addition of a safe water supply brings is that of health. Worldwide, 25,000 people die every day due to unsafe water (International Institute for Environment and Development, 2000). In contrast, the addition of boreholes to sites in Nigeria is reported to have reduced ‘important’ illnesses by around 50% (Nogier, 1998). However, there can still be health issues if the PVP system and borehole are not designed and maintained suitably. If a safe water output is to be sustained a number of factors need consideration, including: good borehole design and siting; good design of the surroundings at the borehole and reservoir outlets; and, again, good maintenance of all parts of the system including the borehole. Failure to correctly oversee the watering station can result in unhygienic practices, which may include contamination from livestock (MacMillan, 2001), development of stagnant pools—a breeding ground for disease-carrying insects—and similar problems. Issues such as these are predominantly down to good social management and community involvement, along with health education, rather than technological solutions. The consequences on health of the failure of a PVP system can be quite extreme. Whilst large numbers of toxins may be present in traditional water sources, the users can build up immunity over a period of time. When a new pump system is implemented, lack of exposure to the toxins may lead to weakening or loss of this immunity. Should the users then revert to the old water source, because of pump failure for example, they will therefore succumb to what could now be life-threatening illnesses (Hazeltine and Bull, 1999). Clearly therefore, not only should the PVP be designed to be reliable, it should also be designed for the minimum down-time when repair is required and this requires that the pump be designed within the appropriate technology / VLOM principles.
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5.7. Economic The increase in health has far-reaching effects, including increased economic prosperity as more water and / or more time is available for commercial activities. The local economy can further reap significant benefits from the presence of a technician skilled in PVP installation and maintenance, whilst the extra time made available for women and children can be used for furthering education. PV pumping can be seen as one of a number of steps along the development route and, if well planned and executed through local management committees, allows the local communities to determine this route for themselves. Whether PVPs should be considered to be a first step towards development or a second step after prior introduction of a hand-powered pump, for example, is a question which will not be debated here. There are, however, negative economic aspects, particularly where the purchase of the PVP system is concerned. There is no doubt that PV pumping systems carry a high capital cost, a considerable portion of which is due to the cost of the photovoltaics. Current costs seem likely to preclude those who most need the water unless external organisations, such as governments, aid agencies, or NGOs, become involved. These prohibitive costs, however, are gradually being recognised as ‘offset over time by the minimal running costs’ (Faulkner and Lenehan, 1997). The financial viability of PVPs against hand pumps or diesel generators has been widely considered and results in considerable potential. Faulkner and Lenehan identify the limits of feasibility for PVPs, based on the cost of providing a certain power output from the PV array. Even with these limits they are able to identify 4000 communities in the KwaZulu Natal area of South Africa alone where PVPs are a ‘viable option’. Indeed, they conclude that ‘despite problems of cost and present unfamiliarity, PVP . . . use is likely to increase in the future’ (Faulkner and Lenehan, 1997). The economic viability of PVPs varies both within and between countries and must be known by those seeking to implement them. In addition, the availability of credit and / or aid will play a significant part. Posorski and Haars (1994), for example, considered seven countries over three continents. Whereas they suggested viability in Argentina for all sizes of PVP under 4 kWp with normal credit terms, in Indonesia even special credit conditions could not enable PVPs to compete with other sources. A comparison of the costs of PV, wind and diesel pumping in two areas of Jordan showed PV and wind (mechanical) pumping to be economic against diesel pumps (Hammad, 1995). In a somewhat more up to date consideration of water pumping in India it was difficult to find any conditions—including capital subsidy—under which PVPs could compete successfully with other options, such as diesel or wind
powered pumps (Rubab and Kandpal, 1998). Bannister (2000), however, shows that a 1 kW PVP system in South Africa becomes more economical than a diesel system after just 3 years of operation. Clearly local costs need consideration before proceeding with the design and purchase of a PVP system. Once a system has been purchased and installed, the question of payment for the output water is very difficult, again varying within and between countries. In particular, consideration must be given to who is paying, what the money they are paying goes towards (running costs, recovery of capital cost, maintenance costs or even setting money aside for future replacement), whether the amount required is affordable and, perhaps most importantly, are the people willing to pay for water? Whilst the last point may prove the most contentious—particularly when water can be considered a ‘Fundamental Human Right’ within the bounds of the UN Universal Declaration of Human Rights 1 —many organisations are clearly of the opinion that people will pay for the provision of clean water and that only by doing so will the system be sustainable. Where a community is required to provide some kind of finance for a project it would seem likely that they will ensure that it is appropriately maintained. The failure of pumps, described by Kaunmuang et al. (2001) (see Section 5.1) is primarily put down to a failure of promoting agencies to install a ‘mechanism for water management, including fee collection’ which would in turn have brought about the ¨ community ‘ownership’. On the other hand, Munger (2000) quotes an ‘excellent bill collection rate’ as an indication of user satisfaction (and hence system sustainability) in Mauritania, whilst Enersol Associates clearly aims to ensure recovery of all the costs of installed systems—even to the extent that it ‘maintains the right to remove the PV equipment if . . . [the] community defaults on payments’ (Verani, 2000; Johnson, 2001). The issue then becomes providing an adequate financial mechanism that will allow appropriate credit terms and repayments as per the community’s means and water usage. However, some people are liable to use more water than others, suggesting either some form of metering or water management, or sufficient community ‘spirit’ to allow this without causing conflict. There is a very strong gender aspect to the economy of PVPs due to all property and finances being entirely under the control and ownership of men in many developing countries. Whilst this will not be further considered here, it is clearly a particularly important factor that must be taken into account throughout the system installation and implementation.
1 See Blackman (1999) for a full discussion of the ‘right’ to water and the financing of water supplies.
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5.8. Summary Every project has its own situation, and that situation is defined by the social, economic and technological capabilities of the people involved. None of the individual issues outlined above can therefore exist in isolation—they are all interlinked, with the common feature being that they all impinge directly on the sustainability or otherwise of the PVP system. For example, payment for water seems likely to lead to community ‘ownership’ of the pump. Some sort of mechanism for this payment must therefore be set up, and this mechanism must be appropriate to the institutional and community needs. A single breakdown in one of these areas can prevent sustainability in all areas. The concerns outlined above cannot be assumed to be a fully comprehensive list. For example, one issue not addressed is the potential for population explosion due to the increased health and the attraction to neighbouring villagers. Nor has the need for follow-up from the suppliers been considered. What has been shown is that the application of PVPs is extremely complex, that people have already addressed many of the problems in given situations and that these lessons have rarely been passed on. The PVP system design must therefore bear in mind any number of ideas, ideologies and concerns—failure to do so on a site-specific basis is liable to lead to unsustainability. However, many of these concerns can at least be considered at the design stage and it is this that will now be investigated.
6. Breaking the mould In designing a pump that is to ‘break the mould’—to make use of appropriate technology, and be maintainable at village level—all of the above discussion must be recognised. This incorporates both technological and sociological factors, and whilst the socio-economic arguments may not all seem directly relevant to the design process, it is important not to dismiss them out of hand. For example, one might ask ‘how can a pump be designed to ensure community ownership?’. The answer ‘by ensuring that it is appropriate to the community’ introduces the complex inter-relationship of all the issues. It may prove necessary to consider gender aspects (in maintenance and use), economic aspects (in the payment for the pump), social and health aspects (in its installation) and so on. To produce a well-designed pump, all of these must therefore be borne in mind. The pump under consideration and testing at the University of Durham has been designed within this context and within Dunn’s requirements for ‘appropriate technology’. One of the major considerations was therefore to create a ‘one pump fits all situations’ design, in order to
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allow village-manufactured pumps to be applicable irrespective of site-specific details and at minimum cost. In order to satisfy this, the pump is based on induced flow principles and therefore has a reciprocating piston to drive the water flow. Traditionally, reciprocating pumps are driven from the motor using some kind of cam arrangement, to convert the rotational output of the motor into linear motion at the piston. Should the pump be above ground, various mechanical means can be used for the conversion. Below ground, the situation is more difficult, particularly if the design is aimed at boreholes where the borehole diameter (typically 100 or 150 mm) provides great restriction on the size of the pump components. Nevertheless, some pumps, such as the Fluxinos ‘SOLAFLUX’ or the Divwatt ‘SOLASTAR’ have been able to accomplish this, at the expense of frictional energy loss between a cam shaft and cam. An alternative to a traditional motor is to consider a device that will take electrical energy and convert it directly to linear movement—in the case of providing motive power to a piston, this seems far more sensible than the use of a rotational motor. A number of possibilities in the linear domain exist and have had some, though limited, investigation in the past. Perris and Salameh (1995), for example, describe a surface mounted pump using a linear drive. However, little has been considered for the downborehole situation suggested here, predominantly because of the size restrictions. There are two design solutions currently under investigation at the Durham Centre for Renewable Energy, both running off DC electricity, to remove the necessity for complex (and potentially unreliable) electronics. The first uses an electromagnet to pull (or push, depending on the configuration) an armature attached to a diaphragm. The second option is to use a linear motor directly coupled to a piston / diaphragm arrangement. The two systems are very different in characteristics, for example operating frequency, piston stroke and so on, but share in the potential for VLOM and appropriate technology. For example, it is widely held in the hand-pumping community that PVC pipes are readily available and this can be incorporated into the design of the pump body. Whilst the electromagnetic and linear motor may not be manufactured in developing countries easily, they require no maintenance, have no moving parts in themselves and would not be expected to fail under any realistic circumstances. How does this pump, then, fit in with Dunn’s aims and objectives? 1. Employ local skills. Manufacture—and consequently maintenance—of most parts of the pump presents no problems using local skills. Indeed, some level of direct employment will be provided, in addition to the pump manufacture, by the requirement for a local mechanic to carry out the maintenance and repair. There is also likely to be employment in managing the water supply,
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ensuring the hygiene of the water distribution point and, perhaps, collecting any payment. 2. Employ local material resources. The manufacture of pumps and spare parts using local material resources is certainly possible throughout much of the developing world and the potential exists for a local entrepreneur to set up a business with the majority of the pump manufactured and assembled locally, buying in solely the PV and electromagnetic components. 3. Employ local financial resources. The use of ‘local financial resources’ introduces the problem of the system capital cost. If this is borne through favourable credit terms, some financial system can be set up to pay what can be afforded. This will ensure that the credit is paid off, and long-term maintenance (and perhaps pump replacement) can also be paid for. Furthermore, through requiring some kind of payment for the pump, it seems likely that sustainability will become a real possibility. 4. Be compatible with local culture and practices. This is somewhat harder to deal with at the design stage. Certainly the system design can be made to allow for the possibility of requiring minimal physical strength, allowing both men and women, as appropriate, to carry out maintenance. During operation, however, there seems to be no reason for conflict between the PVP technology and local culture and practices. 5. Satisfy local wishes and needs. These are enshrined in the provision of water. As long as it is recognised that water is the need rather than PVPs, the sustainability of the system is likely to be ensured. By considering Dunn’s criteria at the design stage, therefore, it has proved entirely possible to produce a pump that meets the aims of both ‘appropriate technology’ and VLOM. Whilst the pumps are currently under study at prototype stage, it is anticipated that further reports will demonstrate their true potential to tackle the joint problems of water provision and sustainability in developing countries.
7. Summary and conclusions Appropriate technology and village level operation and maintenance are two design ideologies that, when considered together, can contribute towards the sustainability of solar powered water pumps. Both of these sets of principles, however, have implications beyond technology and into the socio-economic domain within which the technology must operate. Failure to consider these non-technological issues—by designers, manufacturers, suppliers and installers—can lead to situations where the technology becomes unsustainable, as has been demonstrated in many sites throughout the developing world. However, if both the technological and socio-economic situations are recognised, creating a ‘complete picture’ at the system design
stage, the aims of ‘appropriate technology’ and VLOM can be achieved, resulting in great potential for sustainability. Research at the Durham Centre for Renewable Energy has established the existence of design solutions through the use of a linear-electric drive, directly driven by the PV array and coupled to an induced flow pumping system. Should the continued pump testing programme demonstrate the performance that is promised, it seems likely that sustainable PV pumps will become a matter of fact, rather than a matter of luck.
Acknowledgements The authors would like to thank the Nuffield Foundation for supporting Mr. Thompson under the Undergraduate Research Bursary (NUF-URB01) scheme. Dr. Short would also like to acknowledge the support of EPSRC, grant ref. GR / R51537 / 01, in funding his travel to the ISES 2001 Solar World Congress.
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