While the wind and sun grab most of the headlines about renewable power, another source of alternative energy is starting to make some noise—some noise that sounds like a steam whistle, that is.

According to the Geothermal Energy Association (GEA), the U.S. geothermal-power industry continued strong growth in 2009. Specifically, new projects under development in the United States grew by 26 percent, with 188 projects underway in 15 states. When completed, the projects could produce as much as 7,875 megawatts (MW) of new electric power.

To put this into perspective, the projects will add more than 7,000 MW of base load power capacity. That is enough to provide electricity for 7.6 million people, or 20 percent of California’s total power needs, and roughly equivalent to the total power used in California from coal-fired power plants.

While the Golden State provides a good case for illustration, its neighbor Nevada actually leads the nation in tapping new geothermal power. At present, it has more than 3,000 MW of projects under development. However, the fastest growing geothermal-power states in 2009 were Utah, New Mexico, Idaho and Oregon. Respectively, they quadrupled, tripled, doubled, and increased their geothermal power by 50 percent.
According to the GEA, new geothermal-power projects are in progress in 15 states from the Pacific to the Gulf Coast. The association cited new projects in Alaska, Arizona, California, Colorado, Hawaii, Idaho, Louisiana, Mississippi, Nevada, New Mexico, Oregon, Texas, Utah, Washington and Wyoming. In addition to large utility scale power projects, interest is also expanding in small power systems (under 1 MW) in Louisiana, Mississippi, Oregon, Texas and Wyoming.

The GEA gave much of the credit for the industry’s growth to federal tax incentives. It noted that the new federal tax grant provisions authorized in the stimulus bill applied to all of the geothermal-power projects coming on line in 2009. Local renewable standards created an additional incentive.