Pacific Gas & Electric Co. is celebrating the 30th birthday in August of the 1,212-MW Helms Pumped-Storage project on North Fork Kings River in California.
Helms (No. 2735) came on line in 1984 in the Sierra Nevada Mountains 50 miles east of Fresno. It features two reservoirs, four miles of tunnels between them, and three pump-generators that can produce enough electricity to power the cities of Fresno and Oakland. Helms’ three turbine-generators were refurbished in 2012.
During peak electricity demand, water flows down from Courtland Lake at elevation 8,200 feet through the powerhouse into Lake Wishon at 6,500 feet. When there is excess generation on the system, the pump-turbines are reversed to push the water back up to the upper reservoir.
“Helms and our Diablo Canyon (nuclear) power plant give us the unique capability to fully integrate a significant amount of clean energy into the power supply while still ensuring that we can meet the energy demands of our customers,” PG&E Senior Vice President John Conway said. “When it began delivering power 30 years ago, Helms played a key role for California and our customers. That role has only grown as our electric grid has evolved.”
Conway said Helms’ ability to quickly ramp up and down plays a key role in integrating intermittent renewable resources such as wind and solar power into the grid.
In a 2009 Federal Energy Regulatory Commission workshop, Technology Vice President Clark Gellings of the Electric Power Research Institute discussed a plan to support wind generation by using Helms. Gellings said Helms, the largest energy storage facility on the California grid, could provide regulation services when it is in generating mode. He said Helms could be used in combination with Tehachapi area wind generation, which would enable the use of a third pump to store more energy from renewable resources for more hours annually.