US Military Relies On More Renewable Energy

June 01, 2022 by Kevin Clemens

Microgrids with solar arrays and battery storage are playing an increasing role in DoD sustainability efforts.

The U.S. Department of Defense (DoD) is the federal government’s biggest energy consumer. In 2021 it used 77 percent of the government’s total consumption—15 times the energy consumption of the second-place agency, the U.S. Post Office.


The DOD is easily the federal government’s largest energy consumer. Image used courtesy of Jacob Wood/DOD


The U.S. military has focused on renewable energy for decades and its efforts in environmental sustainability and energy efficiency have made strides to reduce energy demand and curb greenhouse gas (GHG) emissions to address climate change.


You’re In The Army Now

In February 2022, the U.S. Army unveiled its Climate Strategy—a framework for long-term climate adaptation and mitigation across the Army.

Per the branch’s summary, “The strategy drives actions to enhance readiness, resiliency and capabilities of the force. By implementing the lines of effort (LOE) outlined in the Army Climate Strategy, the Army will achieve the goals of a resilient and sustainable land force able to operate in all domains with effective adaptation and mitigation measures against climate change, consistent with Army modernization efforts.”

The Army is taking and will continue to take actions that will reduce GHG emissions. Its goals include:

  • Achieve 50% reduction in Army net GHG pollution by 2030, compared to 2005 levels

  • Attain net-zero Army GHG emissions by 2050

  • Proactively consider the security implications of climate change in strategy, planning, acquisition, supply chain, and programming documents and processes


Facilities are the Big Consumers

Among the DoD’s biggest energy uses comes from the energy needed to power, heat and cool buildings in its facilities, including Army and Air Force bases, Navy yards and fuel required for non-tactical vehicles. The largest consumer of installation facility energy in 2020 was the Army, at 36 percent of the military’s total spending. The next-highest user was the Air Force, at 30 percent, and the Navy, at 28 percent.


Microgrid Examples

To address the energy issue, the DoD is building renewable energy and storage microgrid projects for its bases across the country. For example, the California National Guard and U.S. In May, the Army Corps of Engineers began construction of a 51-megawatt (MW), solar and storage microgrid project located on 99 acres at the Joint Forces Training Base in Los Alamitos. The Los Alamitos Microgrid will consist of 28 MW in solar photovoltaic capacity, a 20-MW/40-megawatt-hour (MWh) energy storage system and a 3-MW diesel backup generator. The microgrid is privately funded and under development by Bright Canyon Energy, which will build, own, and operate it. Once operational, the system can isolate the base from the main grid and keep electricity running for up to 14 days. The facility is expected to be operational by the summer of 2023.


The Joint Forces Training Base in Los Alamitos, CA will be powered by a 51-megawatt solar and storage microgrid. Image used courtesy of the U.S. Army


Meanwhile, in Humboldt County, situated along the rugged northern California coast, a microgrid system is under development to serve the Redwood Coast Airport and the U.S. Coast Guard Sector Humboldt Bay Air Station. The Coast Guard station oversees hundreds of miles of coast from Sonoma County to Oregon. The microgrid is the first front-of-the-meter, multi-customer microgrid in the Pacific Gas & Electric (PG&E) territory.

The 2.5-MW solar photovoltaic array can operate in two ways. 2.2 MW is front-of-the-meter and generates power from a 2.3-MW/8.8-MWh energy storage system consisting of three Tesla Megapack batteries. Excess energy can be sold to the California Independent System Operator (CAISO) market.

An additional 300 kilowatts (kW) of solar is behind-the-meter, and it directly supplies the airport facility with electricity as part of the lease arrangement. The microgrid controller communicates directly with PG&E’s distribution control center and CAISO. The site also includes electric vehicle (EV) charging stations. The airport and the Coast Guard Air Station both have diesel generator backup, but the solar and battery storage should be enough to power the facilities even during extended grid power outages. The system also lowers GHG emissions from both the airport and the air station. 


The Time is Now

According to Christine E. Wormuth, Secretary of the Army, “The time to address climate change is now. The effects of climate change have taken a toll on supply chains, damaged our infrastructure, and increased risks to Army Soldiers and families due to natural disasters and extreme weather. The Army must adapt across our entire enterprise and purposefully pursue greenhouse gas mitigation strategies to reduce climate risks. If we do not take action now, across our installations, acquisition and logistics, and training, our options to mitigate these risks will become more constrained with each passing year.”


Feature image used courtesy of Harry Weddington/U.S. Army Corps of Engineers