Air Force's largest solar project planned for Davis-Monthan

Construction of the largest solar energy array in the U.S. Air Force will begin at the end of June on Tucson's Davis-Monthan Air Force Base. The project is expected to save the base $500,000 per year in energy costs.

The cost of installing and maintaining the solar array is the responsibility of Sun Edison, the company building the project, said Greg Noble, Davis-Monthan's energy manager. Sun Edison representatives declined to comment on the cost of the project.  

The 14.5-Megawatt Photo Voltaic Array Project will see 57,000 solar panels cover two sites on 170 acres of unusable land on base, Noble said. The project is expected to be fully operational by mid-December.

The project was originally expected to be completed in 2011, but saw multiple delays. There were several issues that involved regulatory compliance, project funding and contract issues, Noble said. He said that these types of delays were to be expected in projects of this scale.  

To put the 14.5 megawatts in perspective, one megawatt of electricity can power, on average, 1,000 homes for one year.  

The base currently pays 8.6 cents per kilowatt-hour of electricity, but the rate for the power supplied from the solar array will be 4.5 cents, Noble said. That rate is projected to increase by 1.5 percent per year.

The solar arrays will be provided and operated by Sun Edison under a 25-year lease. Tucson Electric Power now provides electricity to Davis-Monthan; after the completion of the new solar project the entire base will be drawing power from both TEP and Sun Edison.

Davis-Monthan's solar array is one of many of the military's alternative energy projects. A new report from the Solar Energy Industries Association, a national trade organization, detailed the growing role of solar energy in the U.S. military.

“As of early 2013, there are more than 130 megawatts of solar photovoltaic energy systems powering Navy, Army and Air Force bases in at least 31 states and the District of Columbia,” said the SEIA report, Enlisting the Sun: Powering the U.S. Military with Solar Energy. “Combined, these installations provide enough clean energy to power 22,000 American homes.”

The completion of the project on Davis-Monthan will bring the base's total megawatts produced by solar energy to 20.5. Six megawatts of solar energy already helps power on-base housing.

In addition to a lower kilowatt-hour rate, D-M will save money by avoiding some electricity demand charges imposed by TEP.

Commercial centers and other customers using large amounts of electricity are not only charged for the actual amount consumed. Facilities like Davis-Monthan have an additional fee, called a "demand charge," levied on top of the base rate. This charge is based on the highest number of kilowatt-hours used during a 15-minute period during a billing period.

Lowering the “demand charges” for the base by using more solar-generated power will also help save money, Noble said.

The Air Force, the largest consumer of energy within the Department of Defense, announced that it would produce one gigawatt of renewable energy by 2016, the SEIA report said. If that goal is met, the Air Force would exceed all DOD energy mandates.

“(Photovoltaic energy) is planned to account for over 70 percent of all new Air Force renewable energy capacity added from 2012 to 2017, which will represent a significant expansion of the USAF’s current solar installations,” the report said.

Large-scale projects, such as the project at Davis-Monthan, aren’t the only way the DOD is harnessing the power of the sun; the military is also using systems that can be carried on the battlefield.

Solar units that can be used in a war zone are referred to as “operational solar,” however, bases in places such as Afghanistan can also produce power from “micro grids” which are similar to the new project at Davis-Monthan but on a much smaller scale, said Will Lent, a research analyst for SEIA and the lead author of the report.

The military spends $15 billion per year on power, and 80 percent of that money goes directly towards purchasing petroleum, said a 2012 GlobalPost report published by TucsonSentinel.com.

A Marine unit serving in Afghanistan reduced the amount of fuel that they used from 20 gallons per day to 2.5 gallons  by harnessing solar energy, GlobalPost reported.

Other changes for the DOD in the future include using solar power to help fuel vehicles such planes, ships and ground vehicles, the report said.

The Department of Defense's first-ever energy efficient aircraft hanger is also planned for D-M.

“This is really just the beginning of the DOD’s implantation of solar [energy]," Lent said. “They have implemented some serious aggressive plans to move forward with hundreds of additional megawatts so we really expect their totals to increase rapidly in the upcoming years.”