The cost of residential solar is dropping, now less than half of what is was in 2010.
Solar is shining, as solar energy is increasingly powering local communities in the U.S.
Here's how the decline in coal use is linked to climate-friendly cars.
Renewable Fuel Standards designate the minimum levels at which several categories of biofuel are consumed through 2022.
Montana's estimated wind power potential is about equal to the electricity consumed by the 19 lighted states.