A quick idea.
Everything can be classified into groups. Its the core of machine learning. Therefor should not the tools in poor areas or slums be classified into groups. The reason is that you can adapt them for the environment and needs. So the idea that these food making machines or tools are cheap to repair, can be run on limited solar power and be effective enough to make money out of.
The real potential for solar energy could very well be for enabling electrically enhanced livelihood and elevated standard of living.
One idea could be for a TV program like Mythbuster to develop needed machines.