Like steem itself , a distributed solution is probably the way to go.
The price of solar installations keeps falling, but I guess for many the capital needed would be still too much.

For me the story of William Kamkwamba was very interesting to read: the economic impact of even the small windmill he made was very big on his family:

• having battery powered light, they did not have to make light by burning oil (which pollutes, created lung problems and which costs a lot of money)
• having power allowed the neighbours to charge their cell phones
• Eventually the more powerful version powered a water pump which allowed them to create 2 harvests a year which made a big impact on the standard of living!
  

So economically it is a question of an investment with a pretty big ROI. Could a Steem powered version be a loan backed by Steemit.com reputation?
That only works if people are willing to participate and value their Steemit.com reputation obviously.
But if they could invest upfront and realise cost savings the loan could pay itself back rather fast.
Also, definitely encourage inventors like William just imagine steemit existed and we could follow his progress day by day ? Just imagine how much faster he could have progressed comparing his ideas with other inventors like him?

You might also enjoy the open source ecology project, I wrote a post about them. They create open source plans free for everyone how to build production tools and machines specifically designed to be built and repairable by the users without heavy investments. I wish these guys were on steemit so I could support them:
https://steemit.com/technology/@the-traveller/world-changing-ideas-open-source-ecology-and-the-global-village-construction-set

Here is an interesing article about solar: I know in India at least it is getting pretty common in rural villages to put up their own installations. They can´t wait for the government to figure it out.
https://www.theguardian.com/sustainable-business/2016/aug/24/renewables-developing-countries-clean-energy-off-grid-investment-climate-change-mobile-money