Military Bases Turn to Microgrids to Withstand Attacks and a Warming Climate

The Department of Defense is pushing its bases to generate their own electricity, aiming to keep operations running during attacks, extreme weather and grid failures. Marine Corps Air Station Miramar in San Diego is one of the clearest examples of how that works in practice.

Col. Thomas Bedell had been in command at Miramar for only a day in July 2021 when the base energy management director told him that the city's power system was straining under a heatwave and that the base microgrid should be started. Bedell said he agreed, then sent a text asking what the microgrid was.

Mick Wasco, who has directed energy management at Miramar since 2010, explained that the base was set up to operate without city power if the local or national grid failed. By 2012, he said, Miramar was producing landfill gas electricity for the base, which he compared to a small city in size.

Drawing on solar power and methane from decomposing garbage in a large San Diego city landfill located within the base, Miramar can operate in a self-contained "island mode" for 21 days. Bedell calls it "aircraft carrier mode" and jokingly refers to the base as the USS Miramar, arguing that redundant energy, water and food make sense if an installation is viewed as a carrier.

The approach is official Pentagon policy. The department wants all bases to be power resilient and carbon neutral by 2050, goals that often align because local renewable sources are frequently the best route to resilience. A Pentagon spokesperson said 90% of key bases worldwide have at least a plan to become energy independent. The department now gets 15.9% of its energy from renewables and expects to reach 25% by 2025.

Tyndall Air Force Base in Florida, devastated by Hurricane Michael in 2018, is being rebuilt with a microgrid constructed by the local utility, Florida Power & Light. Mike Dwyer of the Air Force Natural Disaster Recovery Division said the system is designed to run the Air Force's headquarters building independently for up to four and a half hours. He said the base is still at least three to five years from having a grid that can power the entire installation. Involving industry partners, he said, made the project faster than the Pentagon's usual procurement process.

Lisa Cohn of Microgrid Knowledge said it is encouraging to see the military take an interest in renewables, given that the department is among the world's largest carbon dioxide emitters. She noted that the military tends to deploy new technologies before others do.

Much of the motivation is tactical. Generating power on base reduces the need for fuel convoys, a vulnerability that proved deadly in Afghanistan and Iraq, where convoys struck by roadside bombs accounted for a large share of U.S. military casualties. Brandon Newell, a Marine artilleryman in 2003, recalled his unit outrunning its fuel supply during the push north from Kuwait and sitting for four days waiting for logistics to catch up. He later set up small-scale renewable power at a combat outpost in Helmand, Afghanistan, retired as a colonel, helped stand up the Miramar microgrid and started a company promoting mobile combat energy systems. He said troops care less about carbon neutrality than about whether a solution helps them fight and survive.

Miramar has also shown how military microgrids can support civilian infrastructure. Bedell said the base could serve as a working headquarters for the state or FEMA during storms or heatwaves. During a 2022 heatwave that put California's grid under its heaviest load on record, San Diego Gas & Electric asked whether Miramar could go off city power. The base ran its microgrid during peak hours for 10 days in a row, which Bedell said spared about 3,000 homes from potential blackouts. The Navy also unplugged its docked ships from the city grid.

Bedell said climate change is itself among the threats the military must address. If the armed forces contribute to the problem, he said, that is "creating the problem that we're wanting to solve."