Geothermal energy harnesses heat to drive turbines to generate electricity, or simply pipes the heat into buildings for direct heat. According to the ever-reliable Wikipedia, as of 2007, it generates about ten gigawatts of electricity worldwide, or roughly 0.3 percent of demand, plus another 28 GW of direct heating capacity. With the attention focused on providing climate-change-friendly sources of energy in the U.S., this total could dramatically increase over the next few years. After all, geothermal is a stable source of energy -- it produces at a steady rate, as opposed to wind power, for example, which only works when the wind blows. (Okay, the wind pretty much always blows here, but still). According to the Colorado Renewable Energy Society, we're well situated with "high-temperature resources that are suitable for electricity generation" present in the state. If these resources work out, geothermal could be a hot new addition to our state's burgeoning alternative-energy portfolio.