There are two ways to get electricity from the sun. The first is the one you know: photovoltaic panels transform the light of the sun directly into electricity. The second is to harness the sun's heat. Solar thermal technology — also known as concentrated solar power — uses vast fields of mirrors to focus the heat of the sun to drive an electric turbine. Solar thermal may be low-tech, but in empty desert areas like much of the American southwest, it offers the potential to be a utility-scale replacement for fossil fuels. If that happens, Ausra could be the company to make the leap. Founded by Australian David Mills, who is perhaps the most renowned player in the solar field, Ausra uses a unique reflector technology that Mills developed, which keeps costs lower than many of its solar thermal competitors. The company, funded by top venture capital firms like Kleiner Perkins, just published a study arguing that solar thermal could supply over 90% of the U.S.'s electrical needs — enough to reduce the country's carbon footprint by 40%. Ambitious goals — but ambition is what we need.