The Guam Public Utilities Commission authorized the Guam Power Authority on Aug. 28 to proceed with procurement of a large energy storage system (ESS) intended to provide energy shifting and grid services needed to integrate upcoming renewable projects into the island grid.

PUC legal staff reported that the procurement follows GPA’s Phase 4 renewable resource acquisitions and a system integration study that found stand‑alone batteries and transmission upgrades would be necessary to integrate the new renewable generation. GPA seeks to procure ESS capacity to provide: roughly 90 megawatts / 360 megawatt‑hours for energy shifting; and roughly 180 megawatts / 90 megawatt‑hours for fast response grid services. GPA told commissioners it expects to enter long‑term service agreements (initial term up to 25 years) that place permitting, construction, interconnection, and operating risks with the vendor.

PUC staff noted GPA proposes recovering ESS charges via the fuel‑and‑purchased‑power adjustment (LIEAC) and estimated an illustrative cost addition on the order of 0.02¢ per kilowatt‑hour, pending bids. GPA staff emphasized the procurement is intended to enhance grid stability, allow higher renewable penetration, provide black‑start capability and fast frequency response, and reduce fuel consumption over time. Commissioners asked technical and scheduling questions; staff said final cost impacts depend on competitive bids and recommended PUC approval to allow solicitation to proceed.

A motion to approve the procurement authorization passed unanimously. GPA will return to the PUC with the bid results and any recommended contract awards for contract‑by‑contract review and approval.