Question: I travel quite a lot, and have seen extensive use of geothermal energy in Iceland and some Eastern European countries for district heating. But, I don't get a sense there is much geothermal use for heating in the United States. Is this the case? If it is, why don't we use more geothermal energy for heating homes and buildings? -- Bill T., Santa Fe, New Mexico
Thanks, Bill. Your quick answer is that while there are some geothermal district heating projects in the U.S., you're right, there aren't enough — especially compared to Reykavik, Iceland, which runs entirely on geothermal. The world's largest district heating system, it has been in place since 1930.
Uses for geothermal energy are divided into three main categories: electricity production, geothermal heat pumps and direct use. District heating, the type you are referring to in Iceland and other countries, falls into this third category. This requires setting up geothermal heating on a collaborative basis for an area. One reason for the low rate of development is that the most geologically viable places in the U.S. for geothermal energy are in the west, where cities and towns are spread out, making it far more expensive to install pipelines — whereas European cities tend to be closer together.
With that said, there is definitely a huge resource of possibility for expansion in the U.S. According to John Lund of the Oregon Institute of Technology, about 400 co-located communities (many very small) have been identified within 5 miles of a geothermal resource in the 16 western states. Expanded direct use in the U.S. depends a lot on people learning about it and wanting to develop and pay for it. Currently, there are many systems in place for residential, industrial and commercial uses. According to the Department of Energy website, these uses include homes and offices, commercial greenhouses, fish farms, food processing facilities and gold mining operations.
The Department of the Interior has new rules that may help to promote more direct uses and district heating, particularly given how much of the land in the west is federal public land. Under the new geothermal leasing law, local governments and others can obtain low-cost access to geothermal resources on public lands for public purposes. The BLM and Forest Service are about to issue a west-wide programmatic Environmental Impact Statement for geothermal leasing, which I expect should include an examination of the areas that could be suitable for community, tribal, or other similar uses of geothermal resources. You might watch for its release here.
The benefits of direct use are great for the environment on a global scale, and also, on the other end of the scale, for its users. Liz Battocletti of Bob Lawrence & Associates did a report for the California Energy Commission Geothermal Program on several heating systems in California. Her findings show that six geothermal heating systems offset the emissions from the burning of 1 million gallons of propane and 10 million gallons of fuel oil-equal to 29,353 passenger cars not driven for one year. And according to the DOE Web site, geothermal district heating systems can save consumers 30%-50% of the cost of natural gas heating.
The Department of Energy's Direct Use of Geothermal Energy Web page gives a great outline on how direct use is done, its benefits, and its current use in the U.S.