What a solar pump costs to buy
A solar irrigation pump uses panels to run an electric motor that pulls water from a well, river or borehole, with no fuel needed once it is installed. For a 1 acre farm in Kenya using about 1,000 cubic meters of water a year, a solar pump kit, including panels, a controller, piping and sprinklers, costs 380 dollars upfront. A diesel or petrol motor pump for the same farm costs 260 dollars upfront, and a hand worked manual pump costs 170 dollars. Solar is the most expensive of the 3 pumps to buy. SunCulture, a Kenyan pump maker, sells solar pumps that can move up to 7,960 liters of water an hour, though the yield and income increases advertised on its own site carry no stated method and are not used here.
Solar price includes panels, a controller, piping and sprinklers. Drip irrigation lines are priced separately and not included here.
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| Manual | 170 |
| Diesel or petrol motor | 260 |
| Solar | 380 |
What it costs to run, over 10 years
A diesel pump needs fuel every time it runs. Added up over 10 years of running a pump on that same 1 acre farm, fuel, pipes, upkeep and 1 full pump replacement bring the diesel motor pump to 2,470 dollars. The solar pump, powered by sunlight instead of purchased fuel, totals 1,880 dollars over the same 10 years. The manual pump totals 2,430 dollars, most of it the cost of the labor needed to work it by hand. Over 10 years, solar is the cheapest of the 3 pumps to own.
Totals include pumping, distribution, maintenance and 1 full system replacement over 10 years, using pump lifetimes of 5 years manual, 4 years motor and 7 years solar, as stated by the report.
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| Manual | 2,430 |
| Diesel or petrol motor | 2,470 |
| Solar | 1,880 |
The same story at a bigger scale, in Bangladesh
The Kenya numbers describe a small kit for a 1 acre farm. A pump built for a bigger farm costs more to buy, and still pays that cost back. In Bangladesh, a 4 kilowatt peak solar system, sized by how much power its panels can produce at once, costs about 8,400 dollars to install. Diesel savings and higher crop yields together paid back that cost in 5 years. As of March 2021, the same national program had installed 1,515 solar pumps with about 40 megawatts of combined capacity, and is aiming for 10,000 pumps by 2027, according to the Infrastructure Development Company Limited, the Bangladesh government finance body that runs it.
What farmers do once the water is free
Once a solar pump is paid off, it keeps pumping without a fuel bill, which is what lets farmers change what they grow, not just what they spend. In Zimbabwe, the Ruti Dam irrigation scheme grew from 40 to 60 hectares after farmers switched from diesel to solar pumps. Household income then rose most for the very poorest farmers, up 286%, against 173% for poor households and 47% for middle income households, as fuel costs stopped eating into what they earned from the extra harvest.
Income change reported by an Oxfam evaluation cited in the source, for households after the Ruti Dam scheme expanded irrigated land using solar pumps.
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| Very poor households | 286 |
| Poor households | 173 |
| Middle income households | 47 |
Thanks to solar, I'm saving $2 per day of irrigation and don't have to worry about rising fuel prices anymore
A Bonergie customer, quoted in a 2024 report on small scale irrigation financing. Source 2.
Thanks to my solar pump I made $1K in net profit in just one year by selling tomatoes off season, when the price is at its highest
A SunCulture client in Western Kenya, quoted in the same 2024 report. Source 2.