I'm not going to build this. PV solar cells are far better sources for renewable energy. Hydroelectric or wind power would be good too if I had good flowing water or air around. For the most part, it's still way cheaper for me to tap into the grid and pay for that than any alternative energy sources I have researched. The batteries in renewable power arrays are what turn me off to them. Not only are they expensive, they are far worse for the environment than CO2 emissions. Just distill your own ethanol and run a generator off renewable fuels. Biodiesel works too

I believe this would be the easiest system for him in Africa. The fuel source could be harvested locally or byproducts from his aquaponic systems could be used. The steam can be captured and used for drinking water. The steam turbine can be built with minimal tools. I have not seen conversion ratios, but I recall reading that the Sterling engine had trouble creating anywhere as much power as a steam turbine or engine.

"Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about 80% of all electricity generation in the world is by use of steam turbines." http://en.wikipedia.org/wiki/Steam_turbine