When u say "gas" you are talking about fuel/petroleum etc right? Sorry i am from South Africa, but i'm aware that ppl from the states use the words gasoline (gas). So, if my understanding is correct, then i'd say that that option is to expensive. The petrol (fuel) price is way to expensive over here to be sustainable for poor communities as many of them cannot even have proper access to water.
Man powered is the option I am looking for yes. Solar power generation is still a relatively expensive option commercially, many industries here are changing to solar power as an additional source and we'll be commisioning a solar power station by 2011, i've heard.
But yes, man powered is what i'm looking for...