In Alabama's Blount County, off the highway, down a dirt road and up a hill is writer T.K. Thorne's house. She points to her roof and a shining row of black solar panels.
It's a 4-kilowatt system — pretty typical for residential solar — and Thorne got it almost four years ago hoping to help the environment and reduce her electricity bill.
It was a big investment — $8,400 even after a federal tax break. Thorne estimated how long it would take to pay off the solar system, installed the panels, and began waiting for the savings to begin.