The Power of Geothermal

An expert team of engineers, scientists and business analysts has been dedicated to the identification, development and stewardship of geothermal energy resources on government lands for over 35 years.
By Vincent P. Sobash, P.E., M.SAME, Andrew Sabin, Ph.D., PG, and Capt. Thomas R. Liedke Jr., P.E., M.SAME, USN (Ret.)

Three of the nine 30-MW rated turbine-generator sets and associated water cooled condensers at Navy Unit 1 Power Plant at Coso Geothermal Field, Naval Air Weapons Station China Lake, Calif. Driven by 400°F fluids from 80 production wells on both DOD and DOI/BLM lands, the units have produced more than 30,000-GWh of electricity for Southern California Edison since 1987 with an on-line availability of over 98 percent. PHOTOS COURTESY NAVFAC EXWC GPO

According to the Geothermal Energy Association’s 2013 Annual US Geothermal Power Production and Development Report, the United States has approximately 3,386-MW of installed geothermal capacity— more than any country in the world.

While this capacity is mostly concentrated in California and Nevada, geothermal power plants also are operating or under construction in Alaska, Hawaii, Idaho, New Mexico, Oregon, Utah, Washington and Wyoming. There are about 70 major military installations and vital training ranges in these western states.

Geothermal is a particularly important renewable energy. Depending on the characteristics of the resource—such as temperature, pressure and fluid—geothermal energy can be used directly for heat and indirectly to generate electricity. Geothermal also can provide constant base load power independent of atmospheric conditions, just like conventional non-renewable power plants.

At the Oregon Institute of Technology in Klamath Falls, Ore., geothermal energy has provided heat since 1964. Current annual production levels are 13.7-GWh. Similarly, San Bernardino, Calif., has used geothermal for 30 years in a district heating system that today supplies 37 buildings with an annual production of 22-GWh. Both of these applications are directly analogous to military installation scenarios.


Geothermal is the only readily dispatched source of renewable energy. While wind and solar energy production is variable, geothermal energy is essentially always available. And, without loss, production levels can be adjusted as a function of demand from zero to the capacity of the respective developed resources. As electric power grids become more distributed and as the other fluctuating renewable energy sources provide larger percentages of the total supply capacity, this inherent quality of geothermal energy will become increasingly more valuable.

Although geothermal has great potential and there are many successful applications in the western United States, it is not a panacea, nor is it necessarily available everywhere it is needed. Specifically with regard to military installations, while there are many large bases in the Known Geothermal Resource Areas identified by the U.S. Geological Survey, only one full-scale power production facility has been developed to date on land controlled by the Department of Defense (DOD).

The Coso Geothermal Facility has been producing power for Southern California since 1987. With wells and power plants on military ranges and withdrawn lands, this 270-MW facility is a model for geothermal development benefitting the civilian community while maintaining military mission primacy. Initial identification and exploration, development, and on-going stewardship is led by scientists, engineers and business analysts in the Geothermal Program Office (GPO) at Naval Air Weapons Station China Lake, Calif.

While GPO is part of the Engineering and Expeditionary Warfare Center public works business line within Naval Facilities Engineering Command, its responsibilities extend far beyond its parent branch. Defense Energy Program Policy Memorandum 91-2 directed the Secretary of the Navy to be the lead in “geothermal technology application and resource development.”
In turn, GPO’s mission, as it has been since the office was established in the late 1970s, is the exploration, development and management of geothermal and geothermal-hybrid systems on lands entrusted to our country’s military services. GPO has led efforts at U.S. Army and Air Force installations as well as Navy and Marine Corps sites throughout the western United States. It also is involved with resources outside the Lower 48, from Hawaii to Italy to Djibouti.

Geothermal exploration drilling rig at Hawthorne Army Depot, Nev.

While active stewardship and management of Coso Field (geological and geophysical investigations, compliance, reservoir monitoring and modeling, environmental, liaison, protection of historic sites) remains GPO’s main responsibility, the office is pursuing other exploration and development opportunities in support of national renewable energy and energy assurance initiatives. Recently, the team completed a direct use study for Hawthorne Army Depot, Nev., and an exploratory drilling program at nearby Naval Air Station Fallon. These installations are located within the geothermal rich Basin and Range Physiographic Province and are indicative of the potential to employ geothermal energy at military installations in such areas. At NAS Fallon, exploratory wells have encountered fluids with temperatures over 400°F. If adequate production flow rates can be obtained there is the potential to satisfy all of its electricity and hot water needs.

The exploration work in northwestern Nevada and on lands associated with Naval Air Facility El Centro in Southern California’s Imperial Valley may be very encouraging, but does highlight issues associated with geothermal energy and the importance of GPO’s role to DOD.

Geothermal energy has the highest capacity factor (92 percent) and one of the lowest total system levelized costs/MWh ($89.6) of all power plant sources according to the U.S. Energy Information Administration, but significant costs associated with geothermal development occur during exploration when the return on investment is undefined.

In order to get past some of the initial cost risks and promote development associated with military lands, GPO invests revenue derived from the sale of electricity produced at Coso to do the early exploration work, which helps identify a probable resource. In this way, non-tax dollars are used to enhance the probability of success and increase the interest of private financing for such projects. Additionally, as has been done at NAS Fallon, such ground work has facilitated the effective application of American Recovery and Reinvestment Act funds to advance delineation of a geothermal resource—important information shared freely by GPO.
Additionally, GPO is instrumental in ensuring that potential geothermal development will not encroach on the military mission at an installation. Geothermal fields generally extend well beyond the limits of military lands. The office is a critical link between the military community and the power industry. In fact, GPO’s data is used by the Interagency Land Use Coordination Committee, where DOD and the Department of the Interior’s Bureau of Land Management are addressing encroachment-related issues.

While wind and solar energy production is variable, geothermal energy is essentially always available.


For any military installation, the ideal scenario would be to find a geothermal resource within its fence line of sufficient quality and quantity to satisfy all the electricity and heating needs. Such a scenario could reduce general dependency on fossil fuels; achieve a Net Zero energy state; provide an incredibly robust level of energy assurance (independence from the commercial power grid); and optimally reduce power costs. And while a significant effort still would be needed to delineate and develop such a resource, GPO is equipped to assist and represent the installation and all respective operators in the process.

There also is the potential for a large Coso-type resource development that supports the energy needs of an entire region. Such opportunities combined with related emerging technologies are being pursued by GPO with the Department of Energy, National Laboratories and industry. Potential applications for geothermal energy in addition to electricity generation and domestic heating include heating for anaerobic digesters in waste treatment facilities, enhanced algae growth for biofuel production, and even cooling.

Beyond those installations fortunate to have geothermal resource potential for the supply side of the energy equation, every facility can improve the demand side with the conservation benefits of Ground Source Heat Pump systems for heating and cooling. These systems use the constant temperature of the earth at shallow depths as a more efficient heat transfer mechanism than ambient air temperature associated with conventional systems.


Looking to the future, GPO is working with new technologies such as Enhanced Geothermal Systems that may someday expand the range of developable geothermal energy sites.
The office is ready to assist every military installation with geothermal energy and geothermal-hybrid system questions.

Vincent P. Sobash, P.E., M.SAME, is Contingency Engineer, NAVFAC Pacific; 808-472-1353, or This email address is being protected from spambots. You need JavaScript enabled to view it..

Andrew Sabin, Ph.D., PG, is Geothermal Subject Matter Expert; 760-939-4061, or This email address is being protected from spambots. You need JavaScript enabled to view it..

Capt. Thomas R. Liedke Jr., P.E., M.SAME, USN (Ret.), is Geothermal Program Director, NAVFAC HQ; 202-685-8245, or This email address is being protected from spambots. You need JavaScript enabled to view it..