Beyond the sun, a new wave of clean energy - Entrepreneurs see green in ocean power, methane, old tires and more

Excerpt:
"As policymakers promote alternative energy sources to reduce the United States' emissions of greenhouse gases and its dependence on foreign oil, entrepreneurs are becoming increasingly inventive about finding novel ways to power the economy.

Beyond solar power and wind, which is America's most developed renewable-energy sector, a host of companies are exploring a variety of more obscure technologies. Researchers are trying to come up with ways to turn algae into diesel fuel. In landfills, startups are attempting to wring energy out of waste such as leaves, tires and "car fluff" from junked automobiles."

http://www.msnbc.msn.com/id/20539985/