Father Verspieren and Mali Aqua Viva: Lessons learned from fighting drought and poverty with photovoltaic solar energy in Africa

Almost fifty years after the first installations, I identify the main lessons learned from fighting drought and poverty in Africa with direct solar-powered pumps thanks to Father Bernard Verspieren and Mali Aqua Viva. Six main findings and three main recommendations emerge from the present analysis which are of direct relevance to all Africa’s countries whose population has gone from 438 million in 1977 to 1308 million in 2019, with about 600 million still having no access to electricity. In place of “awareness campaigns”, I recommend to organize practice-oriented workshops on solar-powered irrigation and rainwater harvesting held by professional educators of newly established solar energy national institutes. In agreement with today’s expanded approach to education in solar energy, and with the key adult learning principle of motivation to learn, said education will include the economic and social aspects of distributed “generation” of energy and water from sunlight and rainfall.


Introduction
The achievements of Father Bernard Verspieren in fighting drought in Mali in the mid 1970s pioneering the use of the first electric pumps powered by photovoltaic (PV) electricity has been recounted by Perlin in a seminal book on the history of solar PV energy first published in 1999. 1 Detailing how Verspieren started a photovoltaic water pumps programme for Mali using a direct (battery-free) photovoltaic-powered water pump first developed by Jean Alain Roger, a physicist at the University of Lyon, and Dominique Campana, an undergraduated student who first had the idea to couple directly PV modules and the water pump, Perlin identifies the key factors that made it a model project for developing countries. 1 Said factors were financial participation by the users and the need of a highly skilled and well-equipped maintenance workforce. 1 Today, advanced textbooks 2 detail the specification of PV pumping systems in agriculture, whereas the $ 1 billion (in 2018) global solar pumps market is estimated to grow at over 12% annual growth rate between 2019 and 2027. 3 However, very few scholarly studies appeared in the scientific literature concerning the practical achievements of Father Verspieren in Africa. For example, a search on Google Scholar with the query "Father Bernard Verspieren" as of late February 2020 returned only eight results.
The only brief account returned by the search, is a two-page account authored by Perlin in 2001. 4 Another book 5 provides an industrial perspective on the achievements of Verspieren with solar-powered pumps. Therein Varadi, a pioneer of the solar PV industry, recounts for example how the first solar pumps developed by the French water pump company following the work of Roger and Campana originally used PV modules manufactured in North America and subsequently in France by a joint venture company. 5 In the following, I identify the main lessons learned from fighting drought and poverty in Africa with direct solar pumps thanks to the pioneering efforts of Father Bernard Verspieren and Mali Aqua Viva.
After a brief review of the scientific and technology achievements that led to the introduction of the first direct solar pumps, I discuss the subsequent impact on Africa and the lessons learned. The findings and the recommendations emerging from the present analysis are of direct relevance to all Africa's countries whose population has gone from 438 million in 1977 to 1308 million in 2019, with about 600 million still having no access to electricity.

Technology and practical use-driven innovation
Today, solar pumps powered by PV modules are equipped with an electronic controller using the Maximum Power Point Tracking (MPPT) technology. The same controller provides real-time monitoring of the borehole water levels, storage tank levels, and pump speed. 3 Almost fifty years after the first installations, I identify the main lessons learned from fighting drought and poverty in Africa with direct solar-powered pumps thanks to Father Bernard Verspieren and Mali Aqua Viva. Six main findings and three main recommendations emerge from the present analysis which are of direct relevance to all Africa's countries whose population has gone from 438 million in 1977 to 1308 million in 2019, with about 600 million still having no access to electricity. In place of "awareness campaigns", I recommend to organize practice-oriented workshops on solar-powered irrigation and rainwater harvesting held by professional educators of newly established solar energy national institutes. In agreement with today's expanded approach to education in solar energy, and with the key adult learning principle of motivation to learn, said education will include the economic and social aspects of distributed "generation" of energy and water from sunlight and rainfall.

A B S T R A C T
In the second half of the 1970s the MPPT electronic technology was not yet available, and Roger solved the scientific challenge to directly connect the permanent magnet motor powering the pump directly to the PV array (the electrical source), and the latter pump to the water well. Both sunlight and borehole water levels indeed vary during the day and seasonally.
In 1979 thus Roger published the theory the interaction of photovoltaic arrays with direct current motors as a function of the load leading to "very simple and reliable installation" that "must start in the morning with no external intervention". 6 Since April 1976, Roger's team was monitoring the performance of a 0.5 kW solar pump consisting of an immersed centrifugal pump connected to a surface direct current motor through a 10 m shaft. 7 Installed in the South Corsica mountains to supply extra water to a sheep ranch, the pump was able to extract a large amount of water "enough to raise 200 sheep as well as pigs and poultry pus a market garden". 8 From then on, wrote Perlin more than twenty years later, "those seriously interested in solar water pumping ventured through the challenging Corsican terrain to see the apparatus at work". 1 Amid them was Father Verspieren who commissioned two such pumps to be installed in Mali. The one installed in late 1977 and inaugurated in the village of Nabasso in February 1978 ( Figure 1), was able to produce 30 m 3 of water per day "to the wonder and joy" wrote a few weeks later editors at New Scientist "of the 2000 parched folk so that they can keep 800 sheep and raise…vegetable patches on land formerly barren for most of the year". 8 Water abstracted from the week indeed was collected in a storage tank and made freely available to villagers.
Two years later, talking as invited speaker to the delegates of the Photovoltaic Solar Energy Conference meeting in Cannes, France, Verspieren emphasized how: «I would say that for me the question of the cost is secondary. What matters above all is the reliability from which it depends on the viability of our populations. I speak to you with full knowledge of the facts, because I currently have in my project sixteen pumps in activity, that is to say 21,800 Watts outgoing daily a total of 1,500 m 3 /day. «Sometimes the enemies of photovoltaics, when they visit our stations pumping, ignoring the cause of the failures, attribute to the PV modules failures which actually come from the pump part (plugged strainer, deteriorated bearings, sometimes also breakdowns are caused by deficiencies in the drilling system).
«We do everything to enlighten them but all technicians are not honest and the slander is international». 9 In other words, in two years only the drilling company (Mali Aqua Viva) established by Verspiaren in 1974 following a request of Mali's government had already installed 16 solar pumps powered by PV arrays whose overall peak power did not reach 22 kW and still were producing (extracting) 1.5 million L of water per day.
At the same conference held in Cannes Verspieren also explained how the laminated plastic surface of solar modules exposed to sun, wind and sand in the Sahel had deteriorated, calling the solar industry to develop new PV module coatings capable to resist under the demanding Sahel's weather conditions. 9 "The engineers" underlines social anthropologist Cross "responded by developing a more rugged design and more durable moulded glass panel which more completely sealed the cells and their connections from contaminants". 10 This shows how "scientific and technical knowledge that was critical to the development of the conventional silicon-based solar photovoltaic module… was produced not in the laboratories spaces of Europe and North America but in field laboratories across the non-western world". 10 In late 1981, reviewing the state of the art of water and photovoltaics for developing countries with "over 200 photovoltaic pumps installed all over the world, mainly in Africa (Senegal, Mali and Niger)", 11 Roger could already conclude that in light of progress occurred in the previous five years, photovoltaic pumps were competitive with diesel engines for powers of up to 5 kW. 11 In Corsica, where the weather conditions are much milder than in Mali, the solar pump directly coupled to the PV modules showed a high degree of reliability with "no break in the water supply observed during the years that have elapsed". 11

The impact on Africa and lessons learned
Critics of the first solar pumps installed in Nabasso readily identified in the high upfront cost their main drawback was. Verspieren was aware of the problem and addressing the audience of the Cannes conference in 1980 said: «Many criticize our installations claiming that the investment is too large, and this because they calculate the price of one cubic meter of water on a one-year basis. This is a wrong calculation because we think we can maintain our installations for 10 years, given that the manufacturers guarantee the system for 5 years». 9 New PV modules coated with tempered glass using new sealing resin were shortly made available by the early PV industry. Eventually, some 125 solar pumps were installed and managed by the Mali's company. 12 The approach followed by Verspieren for which each village had to co-finance and self-maintain their own solar pumps turned out to be successful. 1 Within 1986 Mali Aqua Viva replaced all the pumps with shaft-free, self-lubricating immersed pumps with motor in stainless steel and the pipe carrying the water in plastic. 1 The new pumps, powered by alternate current produced by a small inverter placed above the well, required maintenance every 2.5 years, whereas the previous pumps required 6-to-10 maintenance visits per year. 1 The only problem encountered was the frequent theft of solar modules after 1997. 12 The achievements fighting water scarcity in Mali were known in Europe since the early 1980s. The European Commission thus funded in 1986 the first round of the Regional Solar Programme to install solar-powered pumps in rural areas of Burkina Faso, Cape Verde, Guinea Bissau, Mauritania, Senegal, Mali, Chad, Niger and Gambia. Eventually, three million people gained access to drinking water between 1986 and 2007 thanks to the 1091 solarpowered pumps installed in the course of the two rounds of the Programme (626 in the first round, and 425 in the second). 13 The provision of said systems was largely due to the pioneering efforts of Father Verspieren.
Even the approach followed when installing the systems for free was similar to that pioneered by Verspieren because the villagers had to bear the operation (i.e., maintenance and surveillance) costs. 13 Eventually some 30 per cent of the PV modules installed during the aforementioned European-funded programme were stolen. Only in Senegal as of 2005 some 15 per cent of solar panels installed in the country had been stolen, leading country's officers to conclude that "before going ahead with investments in equipment, it is essential to secure solar installations". 14 It is enough to access pictures of the early installations in Nabasso ( Figure 2) to notice that the solar-powered pump was indeed fenced. Furthermore, a year 2000 video on Teriya Bugu centre for rural development founded by Verspieren shows how all the PV modules of a relatively large installation next to a river from which water is abstracted to irrigate fruit trees and for aquaculture, were welded, surrounded by fencing and guarded night and day by villagers. 15

The key need for education
Verspieren, who studied also agricultural engineering, understood the need to educate and shape a local maintenance staff to ensure proper functioning of the solar-powered pumps. Hence, at a time when education on solar energy and applied photovoltaics was rare even in Europe or in North America, he asked the solar water pump manufacturer to locally train selected villagers.
Forty years later training was still recognized of fundamental importance by the Food and Agriculture Organization (FAO) of the UN organizing a workshop on solar powered irrigation in Kigali, Rwanda, with several companies showcasing solar powered irrigation systems and financial models for their uptake. 16 In the same Rwanda, a farmer using a solar-powered water pump to irrigate an 8 hectare crop field in the Eastern Province, after installing the solar pump in 2016 saw the harvest of beans going from about one tonne of beans per ha, to 2.5 tonnes of beans per ha. 17 Only a single solar borehole pump company based in South Africa between 2009 and 2019 has supplied more than 3000 solar pumps to farms in South Africa, Botswana, Lesotho, Malawi, Mozambique, Namibia, Zimbabwe and Zambia. 18 In a 2018 overview of solar-powered irrigation, the FAO emphasized how the technology would pose a risk to water wells depletion, recommending to include solar-powered irrigation "in curricula for agricultural extension services, irrigation managers, technicians and technical government staff" 19 as well as to launch new courses "to train farmers on more water-efficient irrigation methods, cropping patterns and soil management". 19 To prevent any water depletion risk it is enough to use the solar-powered irrigation systems to pump water harvested during the yearly rainfall. 20 Hence, in place of "awareness campaigns", I recommend to organize, in Africa and in all regions of the world affected by water scarcity, practice-oriented workshops held by professional educators with a clear objective: transfer key concepts and skills in solar-powered pump irrigation and rainwater harvesting.
Being practice-oriented, each workshop (Table 1) provides practical and relevant information with the aid of visual references for each concept and technology illustrated, with case studies and technologies presented by industry's practitioners and by farmers already using these methods.
The number of attendees per workshop should be limited to 15 and answer all key practical and relevant questions. As put it by Steinert, active participation via questions and group discussion is one key ingredients of any successful workshop. 21 A group size exceeding the 15 threshold makes active participation less feasible since it becomes increasingly difficult for trainers to manage questions and make the training personal. In agreement with today's expanded approach to education in solar energy 22 and with the key adult learning principle of motivation to learn, 23 the workshop will include economic and financial aspects of rainwater harvesting, water management, and solar-powered irrigation as central aspects of the training programme.

Lessons learned and recommendations
Reviewing the achievements with solar-powered pumps and solar-powered irrigation started by Father Bernard Verspieren in Mali in the late 1970s teaches six main lessons of general validity for all Africa's countries.
First, at a time when the price of photovoltaic modules exceeded $13/W (between 1975 and 1978 the solar cell module price dropped from about $35/W to $13/W) 24 and their supply was restricted to a few companies with a yearly global production output limited to 100 kW, their use to power directly connected pumps was found to be more convenient than diesel-powered pumps for powers up to 5 kW. 11 Second, as early as of 1980 Father Verspieren was reporting about "enemies of the photovoltaic technology" wrongly ascribing to PV solar cell and module failure of the solarpowered pumps problem that were instead due to pumps. 9 Third, as already noted by several scholars, 10,1 Verspieren's analysis of the problems encountered by the PV modules in the solar-powered pumps initiated key advances in the manufacture of solar modules which led to a first dramatic extension of their longevity, and thus to a significant reduction in the cost of solar electricity supplied during the module lifetime.
Fourth, at a time when the internet did not exist, Father Verspieren understood the importance of communicating the results of his community's efforts to all the stakeholders across the world. He travelled to international conferences in Europe and elswhere, and disseminated the outcomes of an initiative that otherwise would remain confined to Mali.
Fifth, long before than the relevance of social science to energy research was acknowledged, 25 Verspieren understood the relevance of the social involvement in the uptake of a technology until then completely unknown to its users. Hence, he required villagers to be responsible for the maintenance and surveillance of the solar pumps, and to share the financial costs of the new systems. Accordingly, all solar pumps were considered by the population of high social and economic value, fenced and guarded against theft, a cultural and social trait that plagues solar PV installations across Sub-Saharan Africa still today. 26 Sixth, a large part of the water abstracted from boreholes with the aid of the solar-powered pumps was used for productive purposes, namely for irrigating agricultural crops and even to make bricks. This, noted Verspieren in 1980, 9 led to economic growth and prevented villagers from abandoning their village or become unemployed.
Since the uptake of the first direct solar pumps in Mali, Africa's population has gone from 438 million in 1977 to 1308 million in 2019. Yet, about 600 million people in Africa still had no access to electricity by the end of 2019, when only 5 GW of solar PV were installed across the whole continent. 27 This makes Verspieren's pioneering efforts of direct and practical relevance to virtually all African countries.
Today, indeed, mainstream 60 cell modules of peak power between 275 and 295 W are more than twice more efficient than in 1977, and sell at about $0.25/W, 28 whereas the yearly production of solar cells exceeds 120 GW.
Three major recommendations follow therefore by the present analysis.
First, each Africa's country should establish its own national solar energy institute, whose tasks need to include the continuous provision of practice-oriented education aimed to reach farming companies and rural families for the widespread adoption of PV technology and rainwater harvesting to meet their energy and water needs. We have shown elsewhere how this can be done creating public research centres capable to give more useful research, education and policy advice in the fields of solar energy and the bioeconomy. 29 Second, the uptake of solar-powered irrigation systems should take place along with the uptake of rainwater harvesting and efficient water utilization practices. 20 Third, aware that utility-scale electricity production via PV modules coupled to energy storage systems (ESS) based on Liion batteries has lately become competitive with centralized thermoelectric generation, 30 Africa's policy makers aiming to support industrial development should focus investments on PV technology coupled to ESS, and local (and affordable) energy distribution grids.
As to the "ennemis du photovoltaïque" 9 doubting today about its technical and economical feasibility --as their ancestors did in the late 1970s after visiting the first solarpowered pumps in Mali --updated education in solar energy of young professionals from companies and other sectors of the civil society based on the same "practical and relevant information" invoked by Steinert 21 will overcome obstacles and open the route to general uptake of solar energy for all end energy uses.