Overall, Wanjiru seems happy with the machine, which she’s been using since December 2025. It makes running her business cheaper. About 40% of what shop owners who use diesel-powered mills charge customers goes toward paying for fuel, according to Carr, whereas operating Agsol’s solar-powered machine can be up to 80% more profitable once the initial cost (about $1,300) is paid off, which takes between six and 12 months. Wanjiru also likes the fact that—unlike diesel-burning models—her mill can handle very small amounts of grain, which has brought a few new customers her way.  

Carr launched the first Agsol product in 2018 in Kenya and has raised over $4 million of investment—much of that via a UK government program that supports clean energy projects in the region. Last year, Agsol sold 530 units. The company, which is based just outside Nairobi, has received orders from as far as Mozambique and Angola.

As we say goodbye to Wanjiru, she turns and bends over burlap sacks half full of peanuts, mung beans, rice, and millet, arranged neatly on wooden pallets on the cement floor. She lifts a scoopful from one of the sacks and dumps its contents on a scale. A customer waits to be served. 

Geoffrey Kamadi is an award-winning freelance journalist based in Nairobi, focusing on science, climate change, environment, technology, and development.