KIPTUSURI, Kenya — For Sara Ruto, the desperate yearning for electricity began last year with the purchase of her first cellphone, a lifeline for receiving small money transfers, contacting relatives in the city or checking chicken prices at the nearest market.

Charging the phone was no simple matter in this farming village far from Kenya’s electric grid.

Every week, Ms. Ruto walked two miles to hire a motorcycle taxi for the three-hour ride to Mogotio, the nearest town with electricity. There, she dropped off her cellphone at a store that recharges phones for 30 cents. Yet the service was in such demand that she had to leave it behind for three full days before returning.

That wearying routine ended in February when the family sold some animals to buy a small Chinese-made solar power system for about $80. Now balanced precariously atop their tin roof, a lone solar panel provides enough electricity to charge the phone and run four bright overhead lights with switches.

“My main motivation was the phone, but this has changed so many other things,” Ms. Ruto said on a recent evening as she relaxed on a bench in the mud-walled shack she shares with her husband and six children.