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Solar irrigation can turn uncertainty into control. Once farmers see that the sun can do more than charge a phone – that it can water a field – everything changes
– Vincent Seremba, CEO, Simusolar Tanzania & Tulima Solar Uganda
As the climate grows hotter and rains become less predictable, small holder farmers are pushed to the edges – planting in shrinking riverbeds, digging channels into wetlands, and straining ecosystems already under pressure. Agriculture sustains most rural households in Tanzania and Uganda, contributing roughly a quarter of national GDP. When farmers struggle due to an unreliable water supply, so does the entire economy.
Until recently, those without irrigation systems had few options. Some bought water by the truckload during the dry season, others relied on diesel pumps, and many simply walked away from farming altogether as the rains became more unpredictable. Most of rural Tanzania and Uganda is fertile, arable, and off-grid – which is an opportunity to put solar to work.
Diesel water pumps can appear as an affordable option at first glance, but then the extra costs come in: for fuel, oil, repairs, and the time or labor needed to keep it running. Filters clog. Engines break. Pumps stall mid-season. And even when everything works, farmers must guard against theft, spillage, or diluted fuel. “You send money for fuel and hope it actually goes into the tank,” Vincent explains. “But sometimes it doesn’t.” For farmers, the choice between diesel and solar quickly becomes one between struggle and stability.
A small petrol pump might cost USD $150-200 upfront, while a solar irrigation system for one to three acres costs between USD $400-700. The sticker shock can scare off customers or investors, but a solar irrigation system works without daily costs. A good system fills a reservoir during the day and irrigates via gravity or drip lines in the evening. Maintenance is minimal with Simusolar pumps – often nothing for five to seven years. “You focus on your crops, not your engine,” Vincent says.
In just a decade, solar home systems have transformed rural life – powering homes, charging phones, running televisions. But the leap from using the sun for electricity in a house to using the sun to water a field remains a mental barrier. “People understand solar for homes,” Vincent explains. “But when you tell them it can run a motor, that you can pump water and irrigate fields – it’s mind-boggling.”
For Simusolar, much of the work is still about awareness: one conversation, one demonstration, one farmer at a time. One of those conversations changed everything for Shija Samson Millinde, a farmer living in Okorongoni, in the south-east of Zanzibar, Tanzania.
Before the pandemic, Samson worked in hotel kitchens and at reception desks. When tourism collapsed, so did his job. All he had left was a single acre of land and a water source. He tried to keep his crops alive with a diesel pump, but the cost was crushing. Then he heard about Simusolar. He took a chance, bought a solar irrigation system on pay-as-you-go (PAYGo) credit, and learned the basics of agronomy as he went.
The impact was growth – fast growth. With steady irrigation, Samson began planting high-value vegetables and herbs like basil, cherry tomatoes, rucola, pochoy, rosemary and mint, supplying the same hotels where he once worked. His farm expanded from one acre to five, complete with greenhouses. Today, he earns enough to support his family and send his children to school – “a life,” Vincent says, “he couldn’t have imagined a few years ago.”
Even more impressive: Samson has become a solar evangelist. “In his neighbourhood alone, he’s brought in 20 more customers,” Vincent says. “All through word of mouth.” By replacing diesel with solar, Samson built a business that grows with the land, not against the climate.
Simusolar’s PAYGo model has worked by allowing customers to slowly pay for their irrigation systems over a longer period of time, helping make their pumps more accessible to the customers who need them. But the flip side of PAYGo is that it ties up the company’s capital for up to two years while customers repay, which slows down the ability to scale.
In Uganda, partial subsidies and flexible bank financing are helping more farmers take the leap into solar irrigation. In Tanzania, these programs are still limited, which slows adoption. Even small amounts of support can make a big difference in helping farmers afford a system and see the benefits firsthand.
“In Uganda, the banks are moving faster,” Vincent says. “We work with Vision Fund, Centenary Bank, Equity Bank, Housing Finance, EnVenture, and others. Farmers pay a small deposit – maybe 10 to 25% – and then repay after harvest.”
per year, terms up to 5 years (Tulima customers repay in 1–2 years)
per month, terms up to 12 months
per year, terms up to 5 years (Tulima customers repay in 1–2 years)
per month, terms up to 12 months
It’s a natural fit: banks handle credit, while Simusolar handles technology and service. “We’re good at technology,” Vincent says. “And the banks are good at finance. So everyone wins.”
In Tanzania, while progress is slower, there is some promising action. Green finance is flowing through institutions like Equity Bank, CRDB and Victoria Finance, though banks are still adapting to smaller, more flexible agricultural lending models. “They’re warming up,” Vincent says, “and it’s coming.”
per month on reducing balance, terms up to 2 years
per month on reducing balance, terms up to 12 months
per month on reducing balance, terms up to 2 years
Each solar pump installed does more than replace a diesel engine, it reshapes the local economy.
Simusolar now employs about 40 commercial staff across Uganda and Tanzania, each managing five local agents who earn commissions by referring new customers. Many are farmers or government extension workers who already understand local challenges. As demand grows, the most successful agents become full-time staff.
Solar irrigation also creates jobs for installers, field technicians, logistics providers, and local retailers. The diesel economy may lose a fuel-runner or two but, as Vincent puts it, “ten new jobs replace every one that disappears.”
Salahe joined Simusolar in 2020 as a Sales Trainee straight out of university.
Today: Commercial Manager (2025), leading strategy, partnerships, and commercial growth
Vincent’s own story mirrors the journey of his company. Born in Uganda, raised in Botswana, and educated in the US, he carries both rural and urban influences: his grandparents were coffee farmers, while his parents moved to the city. After earing a masters degree in engineering and business and working for leading finance and engineering companies, Vincent returned to Uganda. When Simusolar expanded to Uganda and opened Tulima Solar, he purchased land 45 minutes from Kampala, in Nakifuma, and started farming again – partly to understand his customers, partly to reconnect with his roots.
He experienced what every smallholder knows: the waiting for rain that doesn’t come, the anxiety of a drying field, and the satisfaction of watching a solar-powered pump fill a tank under the sun. Reliable irrigation was a game-changer for Vincent as much as it was for the customers his company services. “I had to believe in what I was selling,” he says. “And now I see how farming can lead to sustainable, generational wealth – it really is transformational.”
In a region where rainfall is increasingly unpredictable, access to reliable energy for irrigation is the very foundation of food security. And as farmers like Samson and leaders like Vincent keep putting solar to work as a tool for climate mitigation, the future of farming is beginning to look a lot more certain.
This article is part of a the Putting Solar to Work series, which highlights GOGLA member companies working in productive uses such as cooling, irrigating or milling.
The IKEA Foundation is supporting GOGLA to strengthen and develop the global industry around Productive Use of Renewable Energy (PURE).
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