Minnesota has more geothermal energy potential than first thought. John Myers from the Duluth News Tribune
reports on progress from NRRI researchers from UMD and North Dakota. West and Central Minnesota have the greatest potential. The closed loop water system involves drilling 20,000 feet (6,096 meters) below the earth surface. Temperatures at this location reach 120 degrees Celsius or 250 degrees F.
Cost for electricity generated by this method is estimated at approximately 10 cents per kilowatt hour. On the plus side it is less variable than wind energy and does not produce carbon dioxide. On the minus side, there are concerns about ground water polution.
The use of carbon dioxide as a gas to transfer heat was discussed in a previous
blog post. The well would not have to be as deep. The cost may also be less.
The US 48 states with more geothermal potential are in red. Those with less potential are in blue.