Geothermal Energy Data and Potential
As a contributing partner of a national coalition, the Michigan Geological Repository for Research and Education at Western Michigan University has been collecting data from across the state that will aid industry in the identification and development of geothermal energy, and it has integrated that data into the National Geothermal Data System. These data are available to all those interested in developing geothermal energy resources.
The National Geothermal Data System is a distributed data system providing access to information resources related to geothermal energy from a network of data providers. Data are contributed by academic researchers, private industry and state and federal agencies. Funded by the Department of Energy’s Geothermal Technology Office, the NGDS provides information to help accelerate the development of United States geothermal resources and can be used to:
- Assess geothermal potential.
- Help potential investors evaluate potential income, expenses and long-term cash flow.
- Reduce risks in exploration and development of this energy source.
- Guide land-use planners and governmental agencies in making decisions about community development.
Geothermal Energy Potential for Michigan
Dr. William B. Harrison III, director of MGRRE, directs this research for Michigan. According to Harrison, "This project will help us understand the geothermal potential in Michigan to an extent never possible before. It's exciting to be part of this national effort to address this potential energy source for the state, as well as for the country."
The geothermal energy in Michigan is not as obvious as it is in western states that have geysers and hot springs. In fact, most states don't have that kind of readily accessible geothermal energy. "What we are looking for in Michigan," says Harrison, "is geothermal energy found in naturally occurring hot brines in deep rock formations." For the first two years of the project, he amassed data from wells drilled through subsurface rocks in Michigan, but especially those deeper than 10,000 feet deep. Harrison searched for that data in two types of well tests originally conducted by oil and gas companies when they drilled deep wells: drill stem tests and temperature records on wireline logs. Those companies needed to know what the pressure in the rocks was and how fluids would flow through them. The tests also secured temperature data.
Other data compiled and provided to the United States Geological Survey's National Catalog included water chemistry information and borehole lithology records. Special emphasis was focused in the third year on shallow unconsolidated formations to identify lithology properties for evaluation of heat flow characteristics to plan and design shallow geothermal heat exchange systems. Michigan already has tens of thousands of shallow geothermal heat pump installations for commercial and residential use. One data set that was compiled documented a number of those shallow units. Because Michigan’s geothermal gradient is low, depths greater than 10,000 feet need to be reached before formation temperatures exceed the boiling point of water. This limits the application of high temperature geothermal technology for power generation. However, low temperature heat exchange systems can be of significant economic benefit for household or small industrial heating and cooling supplementation.
Other states are seeing an advantage in the possibility of using their many existing deep depleted or dry wells to extract energy from hot brine fluids, which would save millions of dollars in drilling these deep wells. Harrison says that might be a possibility in Michigan as well—but first we need the data so that we know where these hot fluids can be found. Although high temperature fluids may not be easily accessible except with very deep wells, waste water production from deep oil and gas wells or some other industrial or mineral wells may be available as access points to this hot water.
By compiling all the geothermal data from each state into one data system, companies can more easily find the right places to produce geothermal energy throughout the country, which is essential to developing this renewable energy resource.
Geothermal Data Compiled by MGRRE
Geothermal data from this research in Michigan can be found in the links below which list all the well sources with locations, depths and temperatures.
- Michigan geothermal data: Michigan-specific data, Michigan geothermal documents, Michigan borehole temperatures, United States Geoscience Information Network Document Repository.
- Geothermal data by state: Association of American State Geologists data archives.
- Geothermal research programs, some with field demonstrations: The U.S. Department of Energy.
- American Association of Petroleum Geologists Explorer article: "All 50 States Participating—U. S. Geothermal Database Being Created".