Get solar panels. They are a bit pricy (usually the state helps pay for them), but they pay for themselves eventually. They are
extreemly low maintenence, generate all day (even when there's cloud cover), and cause near to zero environmental damage. They fit every qualification you asked for save for the price. A friend of mine has a few on his roof, and the eletric company pays
him $5 a month, because his power generation spills over to those around him.
Edit: Austailia is making quite a few breakthroughs in solar technology including lower price. I'll make a thread about it.