Geothermal energy is cheap, clean and constant. Over the next 50 years the U.S. Geological Survey estimates that a new technology known as an enhanced geothermal system (EGS) could supply about 10 percent of the country's current electrical capacity. Unlike conventional power plants that rely on near-surface hydrothermal systems such as springs and geysers, EGS can draw energy from depths of up to three to five kilometers.

Yet drilling for the wells is a financially risky endeavor. Two to five out of every 10 geothermal wells prospected end up dry. Companies need good data on the distribution and quantity of geothermal energy in the upper part of the earth's crust. But apart from using volcanoes as reference points, the data have been hard to come by.

Perhaps not for long, however. The Arizona Geological Survey is leading a coalition of universities and national agencies on a project to find and digitize data from extensive surveys of geothermal resources that were funded in the 1970s, 1980s and 1990s but that have been sitting unused in state and federal filing cabinets for decades. The coalition expects to have as many as three million wells in the system by the end of 2013, and Microsoft Research is using the data to build 3-D interactive maps.