I love your question. As far as I can understand, you're talking about using renewable energy to power _streaming_ projects, as opposed to _broadcast_ projects.
If it's a streaming project, it shouldn't be too hard, because usually the "station" is sending a stream to a data center, where it is retransmitted. Our data center in Germany, for example, has made it a point of running on 100 % wind power.
In terms of broadcast projects, there have been a couple of stations that have run on photovoltaic solar panels, most notably KRUU-FM in Fairfield, Iowa.
But even with the rapidly falling price of photovoltaic panels, you're still talking usually about an investment in the USD $75,000-$100,000 range, which is out of reach for most community radio stations, who are usually a hairs' breadth away from financial difficulty anyway.
That said, our sister organization, the Media Development Loan Fund, has also worked with one of its clients in Indonesia - the radio network KBR 68H - to build hydroelectric generators for stations near large enough water sources. That's a pretty limited use case (you have to have a station close enough to a river), but it does work for a few.
I'd also be interested to hear more about your efforts in this area too.
Best regards,
doug
Douglas Arellanes Director of Innovation Sourcefabric, o.p.s.