Afromusings points to a report on a $450 “solar concentrator” “Specifically for Africa:First of all, the concentrator can be bought as part of a co-op project. Combine it with a water pump, and you have a way of pumping water from either a borehole or a small dam. Add drip irrigation (You might need a second solar concentrator for that) and you have increased productivity despite the lack of rains. Other applications abound, and are too numerous for me to get into now.”