Compare power plants

Registry, engineering, and operating metrics shown on a consistent EIA basis.

Metric	Dion R Holm Tuolumne County	Mammoth Pool Madera County
Capacity	180.2 MW	190 MW
Technology	Conventional Hydroelectric	Conventional Hydroelectric
Operator	City & County of San Francisco	Southern California Edison Co
Operating units	2	2
Latest 12-month generation	550.4 GWh	571.5 GWh
Latest complete-year capacity factor	36.6% (2025)	28.0% (2025)
National technology rank	#77 of 1,349	#73 of 1,349
Latest EIA report	2026-06	2026-06

Generation comes from EIA-923. Capacity, unit counts, technology, and reporting relationships come from EIA-860. Incomplete reporting years are excluded from capacity-factor comparisons.

Compare power plants

Registry, engineering, and operating metrics shown on a consistent EIA basis.

Metric	Dion R Holm Tuolumne County	Mammoth Pool Madera County
Capacity	180.2 MW	190 MW
Technology	Conventional Hydroelectric	Conventional Hydroelectric
Operator	City & County of San Francisco	Southern California Edison Co
Operating units	2	2
Latest 12-month generation	550.4 GWh	571.5 GWh
Latest complete-year capacity factor	36.6% (2025)	28.0% (2025)
National technology rank	#77 of 1,349	#73 of 1,349
Latest EIA report	2026-06	2026-06

Generation comes from EIA-923. Capacity, unit counts, technology, and reporting relationships come from EIA-860. Incomplete reporting years are excluded from capacity-factor comparisons.