The Guam Power Authority said a baseload unit tripped offline Thursday evening, triggering rotating power outages across the island before service was restored later that night.
According to GPA, Piti Unit No. 9 went offline at 6:06 p.m. after an equipment alarm, causing an immediate loss of 42 megawatts and prompting the utility’s automated protection system to shed feeders and stabilize the grid. Customers experienced outages lasting no longer than an hour, with all feeders restored by 8:48 p.m.
Officials said other baseload and combustion turbine units remained online, while Cabras Unit No. 1 is under repair and expected back in service within two weeks. To address capacity shortfalls, GPA is shifting up to 16 megawatt-hours from its battery storage system and has coordinated with Guam Waterworks Authority to run wells on backup generators. The Ukudu Power Plant units remain offline during pre-commissioning testing.
GPA said it continues to work with large commercial and government customers to run on standby generators during peak hours and urged residents to conserve energy between 5 p.m. and 11 p.m. The utility emphasized that rotating outages are a last resort and asked customers to monitor its website and social media for updates.