Hydrothermal - water / temperature (hot springs etc) - more correctly geothermal? Probably. No dams. We don't have 'em. Or nuclear for that matter - only plenty of poisonous coal and diesel fired thingies, as well as hydroelectric.

Hydroelectric - water only - from a great height. Dams and or waterfalls required.

The wind farm at Albany has 12 seriously large turbines (1,800kW) imported from Germany to provide 75% of the power for a city of 30,000, the port and industry. The workings are housed at the top of 65m (200') high towers - each blade is 35m (110') long. Bugs, birds and low flying aircraft wouldn't have a chance.

Albany is a beautiful place....full background on the windfarm and v. pretty pics at:

http://www.westernpower.com.au/our_environment/renewable_energy/wind/photo_gallery.html

stales