NEW YORK Feb 3 PG&E Corp (PCG.N) shut the 404-megawatt Unit 1 at the Helms Pumped Storage hydropower station in California for planned reasons by Monday afternoon, the California Independent System Operator said in a report.
The 1,212 MW Helms station, which entered service in 1984, is located near Fresno in Fresno County. There are three 404 MW Units 1-3 at the station.
Unit 3 shut by Sept. 28 for planned reasons.
All of the other units were available for service.
One MW powers about 700 homes in California.
Pumped storage plants store and produce electricity to supply peak power demands by moving water between reservoirs at different elevations.
At times of low demand and low power cost, the plant uses electricity from the grid to pump water into the higher reservoir. When demand and prices are higher, the station releases the water back into the lower reservoir through a turbine, generating energy.
PG&E's regulated Pacific Gas and Electric Co subsidiary owns and operates the station.
PG&E, of San Francisco, owns and operates more than 6,200 MW of generating capacity, markets energy commodities and transmits and distributes electricity to almost 5.3 million customers and natural gas to 4.2 million customers in northern California. (Reporting by Scott DiSavino)