Installing solar panels or modules to convert sunlight into electricity and conserve energy is not a new concept. Back in 1954, researchers at Bell Laboratories demonstrated the first practical silicon solar cell. But solar power has been heating up over the last 10 years, with a 50% average annual growth rate in the U.S., according to the Solar Energy Industries Association. This is due, in part, to the Solar Investment Tax Credit put in place in 2006 that now reimburses 26% of the cost for solar systems on residential and commercial properties. Other factors have also played a role, including low-interest rates. Homeowners can bundle the cost of panels into their mortgage, says Amy Tovel, marketing manager of Ichijo USA, a company that installs modules on many Pacific Northwest homes.