Power from Not-So-Hot Geothermal

A large share of the geothermal resources suitable for power generation--those with temperatures higher than 300°F--are deep underground, beyond the reach of current technology. Lower-temperature resources, which are common across the United States, are generally used for heating, but could be a bountiful source of power as well, if researchers were able to find an economical way to convert them into electricity.  » original news