<http://schema.org/about>
"Hydroelectric power generally conjures up images of massive dams creating reservoirs behind them, submerging trees and sometimes even towns. While technically a form of renewable energy (and generally included by most countries when"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/renewable-energy/piezoelectric-hydropower-system-may-power-20-40-of-pennsylvania-town.html>