GreenFire Energy is just starting to test its idea to use supercritical CO2 as a driving fluid for a geothermal energy production in Arizona, but online magazine Grist calls it one of "five hot, rockin' geothermal companies." The Moab, Utah company received $2 million in funding from the Dept. of Energy to try out the concept in the St John's area of eastern Utah where a commercial CO2 field is under development by Enhanced Oil Resources, Inc. CO2 may have "higher heat recovery rates and lower pumping costs than water." The CO2 would circulate in a closed loop binary system to transfer geothermal heat to a generator to produce electricity. [right, GreenFire Energy's CO2ETM concept]
