Gianelli Power Plant

The Gianelli Power Plant, also known as the San Luis Power Plant, is a pumped-storage hydroelectric plant that is at the base of the San Luis Dam in California. During the wet season, turbines pump water from the O'Neill Forebay into the reservoir, then when needed during the irrigation season, water flows from the reservoir back through the turbines and generates electricity.^[4] This is an unusual use of pumped storage where the intention is to capture irrigation water not to store power. Storage capacity delivers up to 298 hours of generation at full power.

Gianelli Power Plant[1]
Aerial photograph of the San Luis (William R. Gianelli) Power plant.
Country	United States
Location	Merced County, California
Coordinates	37°03′33″N 121°04′29″W
Status	Operational
Opening date	June 3, 1960 (1960-06-03)
Owner(s)	State of California
Operator(s)	United States Bureau of Reclamation
Upper reservoir
Creates	San Luis Reservoir
Total capacity	2,041,000 acre feet
Lower reservoir
Creates	O'Neill Forebay
Total capacity	56,400 acre feet
Power Station
Hydraulic head	290 feet
Pump-generators	8
Installed capacity	424 MW[2]
Storage capacity	126,352 MW·h[2]
Annual generation	123,48 GW·h (2009)[3] 311,54 GW·h (2012)[3] 111,80 GW·h (2014)[3]
Website usbr.gov