Since 1987, Naval Air Weapons Station China Lake, Calif., has tapped into geothermal wells to produce about 270 megawatts of energy annually — enough to power 180,000 homes and making it the largest renewable energy project within the Defense Department.
But while geothermal energy has been a big part of the Defense Department’s past, tight budgets and difficulties developing geothermal energy mean it will be a smaller portion of the department’s renewable energy future, according to officials, contractors and DoD data.
Geothermal energy is heat stored underground — usually in the form of steam — that can power turbines to create electricity.
The number of renewable energy projects on DoD installations increased from 489 in fiscal 2009 to 679 in fiscal 2012 — an increase driven almost entirely by an increase in solar and wind energy projects.
Nine projects at DoD installations produce geothermal energy, according to the report.
In 2011, geothermal energy use accounted for 74 percent of all renewable energy used by DoD installations. But one year later, that fell to 49 percent, according to the DoD energy management report released in early June. The declining share of geothermal energy was driven mainly by a rapid increase in solar, wind and waste-to-energy projects.
DoD’s analysis of its installations and land shows that geothermal electricity could account for only 5 percent of total possible renewable energy. Solar power can account for up to 39 percent of total possible renewable energy generation, and wind energy, 28 percent. The remainder includes biomass energy — obtained from burning plant material — and ground heat where warm underground air is brought into buildings.
In 2009, the Navy spent $9.1 million to survey and test the potential for geothermal energy at Naval Air Station Fallon, Nev., but only two out of six sites tested high enough for geothermal energy use, according to a 2011 DoD inspector general report. The Navy has yet to move ahead on the construction of a geothermal power plant at those two sites.
Richard Kidd, the Army’s deputy assistant secretary for energy and sustainability, said that while there is potential for geothermal development, it’s a time-consuming and costly process that holds higher risk than installing solar panels. For example, in the case of geothermal, companies have to drill multiple “test wells” to make sure the energy is present.
With a solar project, on the other hand, “if you get a little less sun, your investment doesn’t fail. It just takes longer to pay off,” Kidd said.
Kidd said geothermal energy projects are the costliest of any renewable energy.
Jeff Sherman, director of federal professional services for energy contractor Schneider Electric, said it’s harder to finance a geothermal energy project using an energy savings performance contract (ESPC) than it is for a solar or wind project. That is because the higher costs prevent energy contractors from including them in the packages of retrofits and renovations they offer agencies.
Under an ESPC, the vendor pays the upfront costs of energy retrofits in exchange for payments from energy cost savings over time. The contractor guarantees the energy savings for the life of the contract or has to pay the balance. Contractors are able to include renewable energy, such as solar panels, because their costs can be offset with other energy-saving measures that will save money over time, such as efficient lights or new heating systems. Geothermal projects cannot be scaled down to meet that threshold.
But DoD is not giving up on geothermal as a renewable energy source, Kidd said. The May rollout of a new multiple-award task order contract (MATOC) will allow agencies to more easily enter into renewable energy projects. The first round of the potential $7 billion contract focused on geothermal energy projects, with five pre-approved vendors chosen to help DoD develop geothermal projects in areas where geothermal energy is known to exist.
Among the vendors on the contract are Constellation NewEnergy Inc., ECC Renewables LLC, Enel Green Power North America Inc., LTC Federal LLC and Siemens Government Technologies Inc.
The MATOCs will help installations enter into “power purchase agreements,”under which companies pay for and maintain renewable energy projects in exchange for set energy payments over time. Installations will choose from pre-qualified companies that were vetted by the Army and Army Corps of Engineers. So an installation would only have to pay for the electricity generated by the projects and not for the construction of the geothermal wells.
The Pentagon is pushing to reach ambitious renewable energy goals. The Air Force has said one gigawatt of its energy will come from renewable sources by fiscal 2016. The Department of the Navy said it will reach the same goal by fiscal 2020, and the Army by fiscal 2025.