How many hydro power plants are in CAISO?

CAISO has 196 operating utility-scale hydro power plants with 8.8 GW of capacity, according to the EIA's monthly survey of power plants.

What is the largest hydro power plant in CAISO?

Helms Pumped Storage in Fresno County, California is the largest, at 1,053 MW. It came online in 1984.

How many hydro power plants were built in CAISO in 2025?

0 hydro power plants came online in CAISO in 2025, with 0 MW of capacity.

Who is developing hydro power plants in CAISO?

Interconnection queues list each project under a project company, not the developer behind it. Cleanview researches the developer of every project and has them on paid plans.

Hydro power plants in CAISO

CAISO has 196 operating hydro power plants with 8.8 GW of capacity.

Operating196

Updated monthly. Last updated November 2026.

Under 50 MW50–249 MW250 MW and up

Updated monthly. Last updated November 2026.

CAISO had 194 hydro power plants online in 2016 and 196 in 2026

194

195

196

2016’162017’172018’182019’192020’202021’212022’222023’232024’242025’252026’26

Hydro power plants online at the end of each year. Source: EIA-860M, compiled by Cleanview.

The 10 largest hydro power plants in CAISO

Operating, by capacity

#	Hydro power plant	Location	Year online	Capacity
1	Helms Pumped Storage	Fresno County, California	1984	1,053 MW
2	Edward C Hyatt	Butte County, California	1969	644 MW
3	W R Gianelli	Merced County, California	1968	424 MW
4	Colgate	Yuba County, California	1969	315 MW
5	Devil Canyon	San Bernardino County, California	1994	276 MW
6	Collierville Powerhouse	Calaveras County, California	1989	253 MW
7	J S Eastwood	Fresno County, California	1987	200 MW
8	Mammoth Pool	Madera County, California	1960	190 MW
9	Dion R Holm	Tuolumne County, California	1960	180 MW
10	Big Creek 3	Fresno County, California	1980	175 MW

Hydro power plants that came online most recently in CAISO

Newest first

#	Hydro power plant	Location	Year online	Capacity
1	Waterman Turnout Hydroelectric	San Bernardino County, California	2024	1 MW
2	Friant Hydro Facility	Fresno County, California	2017	38 MW
3	Baker Creek Hydroelectric	Humboldt County, California	2014	2 MW
4	Tulloch	Tuolumne County, California	2012	30 MW
5	Gas Utilization Facility	San Diego County, California	2002	2 MW
6	Diamond Valley Lake	Riverside County, California	2001	30 MW
7	Santa Ana 3	San Bernardino County, California	1999	3 MW
8	Mojave Siphon	San Bernardino County, California	1996	33 MW
9	Etiwanda	San Bernardino County, California	1994	24 MW
10	Devil Canyon	San Bernardino County, California	1994	276 MW

The developer behind each project is on paid plans. See plans

How Cleanview tracks hydro power plants

Operating hydro power plants come from the EIA's monthly survey of power plants. Planned projects come from the grid operators' interconnection queues. We research who is developing each one, since a queue lists a project company, not its owner.

Questions about hydro power plants in CAISO

How many hydro power plants are in CAISO?: CAISO has 196 operating utility-scale hydro power plants with 8.8 GW of capacity, according to the EIA's monthly survey of power plants.
What is the largest hydro power plant in CAISO?: Helms Pumped Storage in Fresno County, California is the largest, at 1,053 MW. It came online in 1984.
How many hydro power plants were built in CAISO in 2025?: 0 hydro power plants came online in CAISO in 2025, with 0 MW of capacity.
Who is developing hydro power plants in CAISO?: Interconnection queues list each project under a project company, not the developer behind it. Cleanview researches the developer of every project and has them on paid plans.