Navy Awards $97M for Battery Storage Microgrid
- Energy Storage Military & Defense News Utility-Scale BESS
Marin Holt
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- 6 minutes read
- NAVFAC awarded a $97 million contract to Granite Construction-Obayashi Corporation joint venture for BESS microgrid at Polaris Point, Naval Base Guam.
- The 17,000 sq ft lithium-ion BESS facility with microgrid controller supports five nuclear-powered fast-attack submarines at Submarine Squadron 15.
- Construction runs from March 20, 2025 through June 2028 with typhoon-rated enclosures designed for 200+ mph winds.
- Granite-Obayashi has completed over $500 million in cumulative DoD contracts on Guam since 2017.
- The project is the Navy first BESS microgrid on Guam, addressing voltage and frequency fluctuations from Guam Power Authority isolated island grid.
Naval Facilities Engineering Command (NAVFAC) awarded a $97 million contract to a Granite Construction-Obayashi Corporation joint venture in March 2025 for a battery energy storage system and microgrid at Polaris Point, Naval Base Guam. The project is the Navy’s first BESS microgrid on Guam and addresses voltage and frequency fluctuations on the island’s commercial power grid that disrupt operations at Submarine Squadron 15’s home port, which supports five nuclear-powered fast-attack submarines across the Indo-Pacific Area of Responsibility. Construction started March 20, 2025 with completion expected June 2028.
Facility Design and Technical Scope
A 17,000-square-foot facility will house lithium-ion battery storage interconnected with a microgrid controller. A second structure supports diesel backup generation. The microgrid controller connects to other Navy distributed energy resources on base and ties to the Guam Power Authority commercial grid, providing the ability to operate in island mode during grid outages. The design must withstand typhoon-force winds exceeding 200 mph and the corrosive tropical marine environment at Polaris Point. NAVFAC coordinated the design with the Guam Power Authority to incorporate lessons from GPA’s Agana BESS installation, which uses similar lithium-ion technology on the civilian grid.
WSP served as the engineering design firm for the BESS system. The project accommodates programming impacts from Typhoon Mawar, which struck Guam in May 2023 and caused widespread infrastructure damage, and aligns with a new primary substation under construction at the base. A separate NAVFAC project is expanding the Polaris Point submarine pier to accommodate up to four Virginia-class submarines or a combination of submarines and a submarine tender.
DoD Energy Resilience Strategy
The Guam BESS project fits within the Department of Defense’s Installation Energy Resilience strategy, which seeks to protect critical military infrastructure from commercial grid disruptions. DoD’s Energy Resilience and Conservation Investment Program (ERCIP) funds projects at installations where grid vulnerability creates mission risk. Guam’s position as a primary forward operating base for Indo-Pacific Command makes grid resilience particularly important, as the island’s single commercial utility serves both civilian and military customers and has limited interconnection with other grids.
The Army awarded a comparable $54.3 million ERCIP microgrid contract to David Boland, Inc. at Fort Stewart-Hunter Army Airfield, Georgia in January 2024, pairing 10 MW of natural gas generation with existing solar PV. The Navy awarded a similar BESS project at Naval Station Norfolk in 2023. The combined military microgrid project pipeline reflects DoD’s multi-billion dollar investment in installation energy independence across all service branches. Granite has committed to subcontracting with local Guam contractors and suppliers as part of the project execution plan.
Critical Analysis
Guam Power Authority isolated island grid delivers voltage and frequency fluctuations that disrupt sensitive submarine base electronics. Guam Power Authority operates an isolated island grid 3,800 miles from the nearest interconnected system.
5-Year Projection
Over the next 5 years, early adopters of Lithium-Ion BESS will set regional cost benchmarks, forcing secondary markets to standardize deployment protocols or risk stranded assets.
Critical Perspective
The Navy awarded $97 million for a battery storage microgrid. This cost per MW appears higher than the 2023 Fort Carson microgrid project which cost $40 million for 12 MW. The Army’s Fort Hood microgrid project in 2017 experienced significant delays and cost overruns. What are the specific risk mitigation strategies for this project’s projected completion date?
