Partly Cloudy Forecast for Solar Energy at Bases

May 2012
By Max Cacas, SIGNAL Magazine


Nellis Air Force Base, just outside of Las Vegas, Nevada, hosts the largest solar array on any U.S. military facility. It is capable of generating 14.2 megawatts of electricity.

Hurdles exist to harnessing the sun, but bright spots still can be found.

Solar energy could help reduce the $4 billion annual electricity bill at U.S. military bases worldwide, with an output of power equivalent to seven nuclear plants possible using the land at just four bases. However, developing the necessary solar infrastructure is complicated both by programmatic and logistical challenges, and these must be overcome before solar will be a cost-effective alternative to power from the grid.

The problems preventing the Defense Department from taking the major steps to turning sunlight into significant energy cost savings are both external and internal, according to a recent congressionally mandated study conducted by ICF International (ICFI) in Fairfax, Virginia.

Bob Kwartin, ICFI vice president, who was the study director and principal author of the report “Solar Energy Development on Department of Defense Installations in the Mojave and Colorado Deserts,” says that two important findings emerged from the study. “One is that there is substantial potential,” he explains, “both technical potential and economic potential to develop solar energy on several of the large military bases in the West. Two, that there’s a very complex policy and programmatic environment which is internal to [the Defense Department] that governs the pace, the attractiveness, the scale at which that potential can be exploited.” The Defense Department has a significant opportunity to develop solar in a way that is economically attractive, Kwartin emphasizes, but “it needs to be done in this complicated context; care needs to be taken; and more resources need to be invested.”

External factors include the condition of the existing electrical transmission grid surrounding most military facilities. The ability to connect any new solar facilities to that grid is limited by transmission lines already running at capacity, Kwartin explains. The decision to build large new solar projects is mainly out of the control of the Defense Department, he points out, adding that governmental and nongovernmental organizations at the federal, state and local levels are involved in the construction of the transmission facilities.

While ICFI estimates that the federal government could earn as much as $100 million annually from surplus electricity produced by base-situated solar energy systems, grid transmission capacity may be a factor in how much surplus electrical power could be sold to the municipal utility. In some cases, transmission grids built with older technology would be unable to handle additional electricity that would be generated by new solar arrays. This could affect any economic expectations for a project. The report recommends that the Defense Department continue to explore the possible use of secure microgrids as one potential way to improve transmission management while enhancing grid security. Microgrids are smaller-scale, local electrical generating and distribution systems that can be disconnected and operated independently from the primary commercial grid (SIGNAL Magazine, February 2012, page 23).

Another challenge is finding enough suitable land. The study, which examined the potential for solar development from the total land area of the nine bases in California and Nevada covering six million acres, found that only 4 percent of that land was viable for development. The land that could not be used for solar energy capabilities was ruled out because of factors including terrain, such as steep hillside slopes; flash flood hazards; cultural resource issues, such as archaeologically and historically significant sites; and proximity to endangered species.

The bases studied in California were Fort Irwin; Naval Air Weapons Station China Lake; the Marine Corps’ Chocolate Mountain Aerial Gunnery Range; Edwards Air Force Base; Marine Corps Logistics Base Barstow; Marine Corps Air Ground Combat Center Twentynine Palms; and Naval Air Facility El Centro. The bases in Nevada were Creech Air Force Base and Nellis Air Force Base.

In spite of these challenges, Kwartin believes the electrical generation potential from the 4 percent of land deemed viable for development constitutes approximately 30 times the electricity now consumed by all of the California bases alone. The ICFI report concludes that solar energy farms on at least Edwards Air Force Base, Fort Irwin, China Lake and Twentynine Palms could generate economically significant amounts of solar energy. The report found that, beyond some solar facilities already in use at Nellis, neither of the two Nevada bases have additional solar energy development potential available for consideration.

Private funding, rather than congressionally appropriated money, would be the most practical way to finance actual construction of solar energy projects on military bases, according to the report. But first, Kwartin says, the Defense Department must resolve internally what kind of authority it has to negotiate with third-party private developers who want to work on solar energy projects. He describes the internal process as “only fully crystallizing now.” The report concluded that it makes no sense for the Defense Department to invest any of its own funds in implementation and construction of solar energy projects. “They should not be using appropriated funds; it’s not cost-effective,” Kwartin suggests.

Current tax incentives, according to Kwartin, favor private development because those incentives make it more economical for private firms, rather than for the Defense Department, to construct solar facilities at military bases. But a window of opportunity slowly is closing on the use of investment tax credits to fund solar development, he warns. Current incentives “allow a developer to write off 30 percent of the cost of the solar installation,” Kwartin reports. This incentive will be reduced to 10 percent in 2017, affecting attractiveness of this kind of investment. He says that now is the time for defense officials to begin a discussion of how they can make public-private partnerships attractive to private developers in order to tap into the potential for solar energy generation identified in the report.

One of the bases examined currently has a solar energy operation that embodies the model of a public-private development partnership, Kwartin explains. Nellis Air Force Base hosts the largest photovoltaic system on a U.S. military facility, using a 14.2-megawatt solar energy array that was completed in 2007. The system was constructed and is being operated under terms of a public-private partnership and contract between the Air Force, a state utility company and private financiers.

Most of the other bases examined as part of the study already use some form of solar energy as part of demonstration projects, with most using smaller-scale arrays capable of generating between 1 to 2 megawatts of solar energy. Kwartin notes that a number of military bases have new solar energy projects now in the design phase. While most people measure the capabilities of solar energy against the size of the installation, as at Nellis, the study found that economics likely will be a significant determining factor in the success or failure of a base solar energy project.

“You want to be selling the output of that solar plant into an expensive electricity market at the wholesale level,” he explains, “or, you want to be selling it to your site host.” A military base could use its solar output to displace expensive retail electricity purchases such as those normally made from the local utility company.

The year-long ICFI study was directed by the Office of the Secretary of Defense. It was conducted in response to a fiscal year 2010 congressional directive to review current solar development activities and to evaluate the potential for new solar energy development inside the boundaries of nine large military installations situated in sun-drenched corners of California and Nevada. The report was supervised by the Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP) in coordination with the Defense Department’s Office of Installations and Environment. Together SERDP and ESTCP are the department’s principal environmental research programs, which collaborate with the Environmental Protection Agency and the Department of Energy on environmental matters.

The findings have been delivered to Congress and to the secretary of defense, who now are studying it to determine a longer-range strategy for integrating solar energy use into the daily operations of military facilities.