A thermoelectric PowerCard like this one can be used to convert waste heat into an electric power source, Alphabet Energy says. Alphabet Energy hide caption

itoggle caption Alphabet Energy

"Physics tells you what you can and can't do. If you know the physics anything else is possible." — Taylor Wilson James Duncan Davidson/TED hide caption

itoggle caption James Duncan Davidson/TED

Jim and Lyn Schneider installed solar panels and batteries because bringing grid power to their house in central Wyoming was going to cost around $80,000. Leigh Paterson/Wyoming Public Radio hide caption

itoggle caption Leigh Paterson/Wyoming Public Radio

President Obama's environmental plan won't be so hard for states that have moved to cut emissions. But for others it will be more difficult. Scott Olson/Getty Images hide caption

itoggle caption Scott Olson/Getty Images

Falling oil prices have put downward pressure on gasoline prices, now averaging $2.65 a gallon — about 85 cents cheaper than a year ago. Gene J. Puskar/AP hide caption

itoggle caption Gene J. Puskar/AP

The first foundation jacket installed by Deepwater Wind in the nation's first offshore wind farm construction project is seen next to a construction crane on Monday, on the waters of the Atlantic Ocean off Block Island, R.I. Stephan Savoia/AP hide caption

itoggle caption Stephan Savoia/AP