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Welcome to the Geological Society of Minnesota

The Geological Society of Minnesota is a public-spirited, nonprofit educational organization that has been in operation since 1938. Our ongoing mission has been to promote public interest and supply educational support in the geological sciences. We do this by sponsoring free lectures and labs at the University of Minnesota, conducting statewide and regional field trips, holding classroom presentations for schools, maintaining a media library, publishing relevant information for public distribution, and maintaining and expanding upon a series of geological markers located throughout the state.

GSM's exciting, illustrated Seminars are presented by leading professionals in their fields of Geology or Earth Science. These engaging talks are free and open to the public, and are especially valuable for enthusiastic learners from secondary school students to adults. A question and answer opportunity is always included. Where else can you enjoy an intriguing exchange with a leading scientist or educator? Our novice-friendly labs demonstrate at a comfortable pace the ideas and principles of geology and earth science. They allow an involved, hands-on learning experience for beginners, or a helpful refresher for the seasoned enthusiast. These instructive sessions are also free and open to the public. Where else can you actively practice science, under expert guidance, for free?

Next GSM lecture:

Geothermal Energy, Energy from the Earth



Joel Renner, M.Sc.

Idaho National Lab(retired)            





Geothermal Energy, as the name implies, is energy from the earth.  Average temperature gradient within all but very young and active crustal areas is about 17°C per kilometer (1°F per 100 feet).  To reach a subsurface temperature of 100°C, such a gradient would require drilling almost 5.3 km (~17,000 ft) where average annual surface temperature is about 10°C.  Drilling to such depths for hot water is not economic now or in the foreseeable future.  So, where do we search for temperature gradients, and in turn, high enough surface temperatures for economic recovery of heat useable at the surface?  Originally exploration for geothermal energy focused on areas of hot springs, fumaroles, geysers and active volcanoes much as early petroleum explorers looked for surface seeps of oil.  Although surface geothermal features are still used for exploration, modern exploration is guided by knowledge of plate tectonics, temperature gradient studies, and structural analysis in areas without obvious surface manifestations.  


Geothermal resources include hydrothermal systems (hot water in the subsurface), hot water co-produced with oil and gas production, heat associated with subsurface bodies of magma and enhanced, or engineered, geothermal systems (EGS) which are hot rocks with insufficient natural porosity and permeability to produce sufficient fluid for economic extraction.  Some geothermal systems contain minerals such as lithium, zinc, lead, antimony, copper and other strategic minerals which may be recoverable with improvements in technology.


The exploration, development and utilization of geothermal energy to produce electricity or directly use the heat are a mixture of technology from the mineral, petroleum and electrical generation industries.  Since hydrothermal-geothermal systems are similar to epithermal ore deposits, the exploration techniques utilized primarily are those of mineral exploration.  Geothermal heat is recovered through drilling of wells and producing the hot water from matrix and fracture porosity in the subsurface.  The technology is borrowed from the petroleum industry with modifications for the higher temperatures.  Electrical generation utilizes turbines and generators similar to those used for fossil fuels but which operate at lower temperatures and pressures.





Summary: Thirty years of research and management related to mineral and energy resources.  Experience includes management of multi-disciplined research groups, business development, resource assessment, evaluation of and technical support to domestic and international exploration programs, and independent research.  


Geothermal Consultant 4/2008 to present - Providing technical expertise on geothermal resources and exploration programs to U. S and international government and private clients.  Co-convener of the Exploration Working Group of the International Partnership for Geothermal Technology.  Member of the U. S Geothermal Energy Association’s Scientific and Technical Advisory Committee.  Member of a technical monitoring team providing expert review and recommendations to about 30 geothermal exploration and enhanced geothermal systems field projects. 

Idaho National Laboratory (INL) 11/1985 to 4/2008: Principal Investigator and Manager of INL Geothermal Program - Internationally recognized expert on geothermal energy.  Led U.S. DOE teams to Africa, the Caribbean and Indonesia to perform pre-feasibility studies related to geothermal development.  Managed $3 million INL geothermal program with Energy Conversion and Geosciences components drawing on mechanical engineering, biotechnology, physics, physical chemistry, reservoir engineering and geology to improve technology related to finding developing and producing geothermal energy.  Managed INL subcontracts for up to $5 million annually for additional research at universities and other DOE national laboratories. 

Provided technical expertise on geothermal resources to U.S. DOE.  Led geothermal-geosciences core research program and supported DOE international geothermal program.  Participated in technical studies utilizing geology, geochemistry and reservoir engineering to understand genesis of geothermal systems.  Managed research program developing reservoir simulation tools for geothermal reservoir management.  Originated studies linking resources and power plants to optimize and sustain geothermal development.  Planed and hosted international cooperative research meetings.  Participated in reviews of technical proposals to U.S. DOE and to California Energy Commission geothermal programs.  Provided technical monitoring and assistance for DOE Geothermal-Geosciences Research grants.  Developed collaborative research with University of Utah, Southern Methodist University and Lawrence Livermore National Laboratory.  Developed and managed research for a model, industry-DOE cost-shared research program. 

MTS Systems Corporation 1984-1985: Marketing and Technical Support - Provided technical support and industry liaison for sales of servo-hydraulic testing equipment for earth science applications. 

Ernest K. Lehmann & Associates 1982-1984: Business Development Manager - Led business development for an international mineral exploration and evaluation consulting firm.  Participated in mineral exploration projects.

Gruy Petroleum Technology 1978-1982: Senior Geologist - Managed contract evaluating geothermal resource potential of eastern United States.  Participated in U.S. Geological Survey assessment of the low-temperature geothermal resources of the U.S.  Prepared and participated in reserve and economic analyses of geothermal resources, oil and gas, tar sands and coal properties.

U.S. Geological Survey 1970-1978: Geologist - Geologic and economic studies of geothermal resources coal, oil shale and saline minerals.  Senior author of hydrothermal-geothermal chapter of first USGS assessment of U.S. geothermal resources.  Lead geologist for first U. S. Department of Interior geothermal lease sale evaluations.



Carleton College, BA Mathematics, 1965

University of Minnesota, MS Geology, Minor Physical Chemistry, 1969

Stanford University, PhD candidacy, Applied Earth Science


Geothermal Resources Council; Board of Directors, 1998-2008, and Aidlin Award recipient

American Association of Petroleum Geologists and Energy Mineral Division

American Geophysical Union

International Geothermal Association

Recent Publications:

DiPippo, Ronald and Renner, J. L., 2013, Geothermal Energy, in, Letcher, T. M., Future Energy:  Improved, Sustainable and Clean Options for Our Planet, Second Edition:  Elsevier, Amsterdam, p. 471 - 492.

Renner, J. L., 2010, EGS – Status and Technology Needs [abs]:  AAPG/SPE/SEG Hedberg Research Conference Enhanced Geothermal Systems, Napa California, March 14-17, 2011.

Renner, J. L., 2009, Geothermal, in, Warwick, P. D., Unconventional Energy Resources: 2007-2008 Review: Natural Resources Research, Volume 18, No. 2, p. 65-83.

Renner, J. L., 2008, Geothermal Energy, in, Letcher, T. M., Future Energy:  Improved, Sustainable and Clean Options for Our Planet:  Elsevier, Amsterdam, p. 211-223.

Renner, J. L., Shook, G. M., Garg, S., Finger, J. T., Kasameyer, P. W., Bloomfield, K. K., Hirtz, P. N., and Mines, G. L., 2007, Geothermal Engineering, in, Warner, H. R., Jr., ed., Emerging and Peripheral Technologies: Society of Petroleum Engineers, Petroleum Engineering Handbook, Volume VI, p. VI-391 – VI- 


Seminars and Labs

The schedule of seminars and labs for 2014-2015 in now available click here . Note that the seminars start a a new time this year, 7:00 PM 

Field Trips

Next field trip: 

During the months of May through October, GSM conducts a series of professionally-guided, statewide and regional field trips. These are one to three day excursions made to points of geologic interest not usually experienced by the casual traveler. They afford a very memorable and satisfying learning experience as there are always plenty of hands-on and question-answering opportunities. A comaraderie with enthusiastic learners and people curious about their natural environment is always a reward in itself. There is a small charge for any shared expense, and a liability waiver must be signed for each participant.


Speakers for metro area elementary schools are available through the Public Service Committee to help enrich the education of young learners, particularly the 2nd to 4th grade levels.


Membership in the society is open to anyone with an interest in geology. The benefits of membership include

  • Extensive Media Library - GSM maintains a collection of more than 125 geological videos and a growing number of interactive, multimedia CD-ROMs for both windows and Macintosh computers. These are available to the members at lectures or through the mail for a nominal rental fee.
  • GSM Newsletter - A quarterly publication containing announcements of upcoming activities, interesting and informative articles on the earth sciences, GSM project and activity reports, and general club news and notices.
  • GSM Directory - An annual book that is a handy information resource, and makes it easy to access your organization.
  • Rocky Roots ... Three Geology Walking Tours of Downtown St. Paul - A free copy of this popular guidebook.
  • The opportunity to meet others of diverse backgrounds who share an enthusiasm for learning and a curiosity for the natural world around them.
  • The rewarding feeling of supporting a public-spirited, nonprofit organization dedicated to public education.
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