Glendale officials say Grayson repowering construction is underway but tariffs threaten battery costs

Glendale Water and Power reported to the City Council on May 13 that demolition and construction work at the Grayson Repowering Project is in progress, but recent federal trade actions and a 90-day pause on some imports threaten to raise equipment costs substantially — especially for the battery energy storage system.

Scott Mellon, acting general manager of Glendale Water and Power, said contractors are at varying stages of completion: roughly 45% complete on the Wärtsilä power island work, about 29% complete on the battery energy storage system (BESS) power island, and 19% complete on the balance-of-site work. He said nearly all civil, structural and mechanical engineering for the Wärtsilä units is complete and most major equipment has been delivered to site, though transformer and switchgear deliveries remain pending. He added that engine blocks were in Long Beach and a permitted pathway to deliver them to the site was recently identified.

Mellon said overall construction man-hours total roughly 171,000 to date and exceed 250,000 if soil improvements and demolition are included. He said the Grayson site layout includes separate zones for engines, transformers, battery racks and power conversion equipment, and that the engine house is sized for three reciprocating internal combustion engines and…