If you’re interested in renewable energy, but are a neophyte on the topic, check out Thames & Kosmos, LLC’s web page in renewable energy kits. These enable you to conduct anywhere from 20-70 experiments across the four kits, two on fuel cells and one each on wind power and sustainable buildings.
They’re not cheap: $50 for the wind power kit to $150 for each of the fuel cell kits at list. They’re discounted somewhat on Amazon, though. Either way, they’re no where near as costly or risky as attempting the real thing if you’re a neophyte.