Anthony M. Wanjohi1 and Peter Gichini2
1,2Kenya Projects Organization
P.O. Box 15509-00503, Mbagathi, Nairobi-Kenya
Corresponding Author Email: wanjohi@kenpro.org
This paper offers an overview of the solar water pumps technologies and market in Kenya. Against the backdrop of Kenya’s increasing reliance on water pumping for food security and limited access to conventional energy sources, the paper explores the market’s evolution. Through case studies and analysis of diverse pump technologies, the paper also showcases successful solar water pumps initiatives, particularly those emerging from public-private partnerships, which have effectively overcome challenges such as financial constraints, managerial intricacies, technical barriers, market access issues, and educational gaps. The aim is to underscore the pivotal role of solar water pumping in sustainable agriculture and economic development. By emphasizing increased irrigated acreage, cost savings, and the cultivation of high-value crops, the paper provides a replicable blueprint for achieving food security in Kenya through innovative application of solar technologies.
Introduction
In Kenya, solar water pumping has evolved into a mature, reliable, and economically attractive solution for off-grid irrigation, livestock water, and community water supply. With the country’s increasing reliance on water pumping for food security and limited access to conventional energy sources in many communities, development programs are actively accelerating the market for solar-powered water pumping systems. Despite facing financial, managerial, technical, market access, and educational challenges, successful initiatives in Kenya, particularly through public-private partnerships, demonstrate the capacity to overcome these barriers. Leveraging relative cost savings, increased reliability of solar power and irrigation systems, and improved technology access through innovative financing models, these interventions serve as examples of how Kenya is successfully advancing the adoption of solar water pumping, addressing critical water needs in diverse sectors.
Water Pump Technologies Deployed in Kenya
In the domain of solar-powered irrigation pumps, various innovative technologies cater to diverse water lifting requirements and environmental conditions. This review delves into the following distinct water pump technologies including Centrifugal Pumps, Piston Pumps, Piston Pumps, Piston Pumps, Reciprocating Displacement Pump, Diaphragm Pumps and Helical Rotor Pumps.
Centrifugal Pumps: Centrifugal pumps are the most prevalent type, known for their widespread use due to their simplicity and efficiency. These pumps operate by utilizing a paddle wheel to suck in liquid, relying on the centrifugal force generated by the rotating impeller. Their straightforward design and versatility make them suitable for a variety of applications, from industrial settings to residential water supply.
Piston Pumps: Piston pumps employ the movement of one or more pistons to draw liquid into the inlet. This mechanism allows for a more controlled and adjustable flow, making piston pumps suitable for applications where precision is essential. Industries requiring accurate dosing or variable flow rates, such as agriculture or certain manufacturing processes, may benefit from the characteristics of piston pumps.
Peristaltic Pumps: Peristaltic pumps utilize rollers to compress a flexible pipe, creating a pressure drop and pushing water up the pipe. This design is advantageous in situations where gentle handling of the liquid is crucial. Peristaltic pumps are often employed in industries where shear-sensitive fluids or delicate pumping conditions are involved, such as pharmaceutical manufacturing or food processing.
Gear Pumps: Gear pumps, operate by using pinions rotating in different directions to push water into the inlet. This gear-driven mechanism makes them suitable for specific industrial applications where a consistent and steady flow is required. Gear pumps are commonly utilized in scenarios where precise fluid transfer is essential, such as in lubrication systems or hydraulic machinery.
Reciprocating Displacement Pump: The SunFlower pump, manufactured by Futurepump in India, is a portable solar irrigation pump utilizing a reciprocating displacement mechanism. This pump operates by raising a close-fitting piston in a submerged pipe, creating a vacuum that draws water up to fill the void. However, this method is limited to a maximum suction height of approximately 10 meters. The piston’s action generates a vacuum, and water is displaced by atmospheric pressure on its external surface, essentially pulled up. The Kenya Smallholder Solar Irrigation (KSSI) project facilitated the deployment of 172 SunFlower pumps, primarily in the Lake Victoria region of Kenya.
Diaphragm Pumps: Diaphragm pumps operate by displacing water through a flexible synthetic material diaphragm, typically with three or four pumping chambers, each equipped with intake and outlet check valves. These pumps efficiently meet low-volume water needs at a cost-effective rate. They are suitable for solar pumping applications with minimal initial cost requirements, low water volume demands, and where occasional maintenance and diaphragm replacement are acceptable. Typically, diaphragms may need replacement every two to three years due to material fatigue and wear, with manufacturers offering replacement kits or entire pump replacements at a low cost. While diaphragm pumps can last longer when operating at lower lifts, they are generally not recommended for communal water pumping systems due to their higher maintenance demands.
Helical Rotor Pumps: A helical rotor pump (HR) stands out as a positive displacement pump, offering a versatile range of volume and lift capacities with high efficiency. It features a single moving part lubricated by water, ensuring a continuous and pulsation-free flow, eliminating the need for preventive maintenance. Known for its simplicity and reliability, the HR pump is particularly effective for flow rates up to ~60 liters per minute and vertical lifts exceeding 20 meters. The pump’s stainless steel rotor fits precisely into a rubber stator with intertwined helixes, forming sealed cavities that draw in water and progress upward as the rotor turns. This progressive cavity pump design ensures efficiency and reliability. Despite its durability, abrasive particles can cause premature wear. The HR pump incorporates a check valve at the outlet to prevent leakage and ease startup, with electronic controllers providing precise control during startup. The Kenya Smallholder Solar Irrigation (KSSI) project facilitated the installation of a significant solar pumping system in Nyandarua county in Kenya, utilizing an HR pump (Foster & Cota, 2009).
Solar Water Pumps Market in Kenya
Between 2000 and 2015, Kenya experienced a marginal increase in basic water supply access, with an annual rate of change at a modest 0.80%. In 2015, the Joint Monitoring Programme reported that 58% of Kenyans (83% in urban areas and 50% in rural areas) had basic water supply, compared to 46% in 2000. However, 42% of the population, approximately 19 million Kenyans, still relied on unimproved sources, with 23% using surface water sources like rivers and dams. These sources pose health risks and are unreliable, particularly in arid areas. Efforts are underway to enhance water, sanitation, and hygiene (WASH) access, especially in rural and marginalized areas, through technical assistance, donor contributions, and initiatives like the Kenya Innovative Finance Facility for Water (KIFFWA), which aims to stimulate private sector investment in water service improvement (Barasa M et al.,2018).
In mid-2015, the introduction of solar water pumps (SWPs) in Kenya, as part of the USAID-funded Kenya Smallholder Solar Irrigation (KSSI) project by Winrock International, featured two affordable and high-quality SWPs: the $450 SunFlower pump by Futurepump (operating up to 10 meters TDH) and the $2,200 SunCulture SP-300 pump (operating up to 50 meters TDH). SWP adoption faced challenges, with retailers struggling to aggregate purchases from smallholder farmers due to financial constraints. Farmer interest was high, but cash limitations hindered SWP ownership. By early 2017, four affordable SWPs were available, including the $350 Majipump MP 400 and the $1,500 D3Solar. Prices fluctuated, with the SunFlower at $650 and the SunCulture SP-300 at $1,740. SunCulture’s new $500 RainMaker pump, claiming high efficiency, was launched in October 2017. Winrock estimated that around 2 million smallholder farmers in Kenya, living in areas with TDH between 10 and 50 meters, could benefit significantly from existing SWPs (Holthaus et al., 2017)
Solar Water Pump Return on Investment Case Studies
Solar drip irrigation in Machakos County
Mr. Shadrack Nzioka, a farmer in Muuani Village, Machakos County, transitioned from using a diesel pump to a solar water pump (SWP) in 2015. With an investment of US $2,670, including a 27-meter borehole, a water tank, and land clearing, he purchased a US $2,500 SunCulture SWP and drip kit with a US $2,000 loan from Equity Bank at 18% interest, making monthly payments of US $100 for two years. The helical rotor solar pump, powered by a 300 Wp solar module, automatically fills a water tank connected to drip irrigation. In the first season, Mr. Nzioka irrigated 0.25 acres of onions, and in the second season, he expanded to a total of 0.875 acres, cultivating onions, passion fruit, and tomatoes. The solar pump enabled him to increase irrigated acreage, eliminate diesel costs, and grow two crops annually. With conservative estimates, he maintains gross profit while paying off the solar pump loan, and projections suggest a 100% increase in gross profit after loan repayment (Winrock, 2017).
Solar irrigation in Homa Bay county
Ms. Lilian Akinyi, a farmer in Homa Bay County, previously used a diesel pump to irrigate her farm near Luala Kambuya village, spending US $5.50 per week on pump rental, petrol, and transport. She cultivated 0.75 acres of tomatoes with the diesel pump and 0.25 acres of kale with a watering can. In September 2016, Ms. Akinyi opted for a Futurepump solar pump through the Pay-As-You-Go program, investing in an 80 Wp solar module and a 12-meter pipe (US $36). She paid a US $236 down payment and committed to a monthly loan payment of US $20 for 22 months, discontinuing the use of the diesel pump. With the solar pump, Ms. Akinyi eliminated diesel-related costs, expanded her irrigated area from 1 to 1.25 acres, introduced a maize crop, and increased irrigation frequency. Conservative estimates project a 186% increase in her gross profit by the second season after purchasing the solar pump, with expectations to further expand to 1.5 acres.
PVWP for drip irrigation in Nyahururu
Patrick Mwendwa, a farmer in Nyahururu, transformed his farming practices with the installation of a Photovoltaic Water Pumping (PVWP) system. Prior to this, he grappled with manual watering, limiting his ability to grow high-water-demand crops like onions. After attending a WI training at a SunCulture demonstration plot, he invested US$3,320 from his savings in a complete PVWP system, including a one-acre drip kit. The system efficiently fills a 10 cubic meter water storage tank, allowing Mwendwa to irrigate his crops effectively. With the new setup, he successfully cultivated onions, a high-value crop, and found lucrative markets, leading to substantial returns on his investment. Now planning to expand his drip-irrigated acreage, Mwendwa’s story illustrates how the PVWP has not only improved farm productivity but also opened up new opportunities for growth and profitability (Winrock, 2017).
PV water pumping for aquaculture and irrigation in Kendu Bay
Winrock International and Futurepump have collaborated in Kendu Bay, implementing a SunFlower Photovoltaic Water Pump (PVWP) at farmer Joshua Okundi’s diverse five-acre farm. This 80 Wp SunFlower PVWP serves multiple functions, including crop irrigation, fishpond oxygenation, and domestic water supply. Mr. Okundi has experienced substantial savings, approximately US$20 per day, by replacing his diesel pump with the solar-powered alternative, which cost US$400 and achieved payback in just one month. The PVWP not only significantly reduced operational costs but also enabled Mr. Okundi to initiate four new income-generating farming activities, showcasing the broader positive impact of sustainable agricultural technologies on both economic prosperity and environmental conservation. Winrock International is actively conducting a detailed cost-benefit analysis at demonstration sites to quantify and document the substantial income benefits associated with Photovoltaic Water Pump systems.
PV water pumping for drip irrigation in Thika
A SunCulture demonstration site near Thika effectively irrigates two off-grid acres using a Chinese-manufactured submersible helical rotor pump situated one meter below the water surface in a pond. The pump, installed in July 2015 for US$2,200, draws water from the pond to fill a 10 cubic meter tank located 20 meters uphill. The tank is replenished twice a week, taking approximately four hours each time. This water is then utilized on a daily basis by the community for drip irrigation across two acres and a nursery. The decision to opt for the PVWP (Photovoltaic Water Pump) was economically advantageous, costing less at US$2,200 compared to the alternative of connecting to the electric grid, which was quoted at US$3,700 with an additional energy consumption charge of US$0.19/kWh. The PVWP investment proved more cost-effective over time, with a lower estimated amortized cost of approximately US$0.12/kWh over 20 years.
Conclusion
In conclusion, the evolution of solar water pumping in Kenya has emerged as a transformative force, offering a mature, reliable, and economically attractive solution to the nation’s pressing water needs. The sector’s growth is propelled by the imperative of achieving food security, coupled with limited access to conventional energy sources in numerous communities. Despite challenges such as financial constraints and technical barriers, successful initiatives, particularly those fostered through public-private partnerships, have demonstrated resilience and innovation in overcoming these obstacles. The introduction of affordable and high-quality solar water pumps, such as the SunFlower and SunCulture SP-300, has been pivotal in expanding water supply options and mitigating reliance on unreliable sources. The deployment of diverse pump technologies showcases adaptability to varying geographical conditions. Case studies exemplify the tangible benefits for farmers, illustrating increased irrigated acreage, cost savings, and the cultivation of high-value crops. The success stories underscore the pivotal role of solar-powered water pumping in sustainable agriculture and economic development. Innovative financing models, such as Pay-As-You-Go programs, have played a crucial role in enhancing affordability and accessibility. As Kenya pursues broader initiatives to improve water access, these achievements offer a replicable blueprint for sustainable development, emphasizing the need for ongoing collaboration between government, private sector stakeholders, and development partners to further propel the adoption of solar water pumping systems across the country.
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