How many pumped storage hydro plants are in Arizona?

3, with 235 MW of nameplate capacity between them, spread over 1 county. That is the EIA-860M operating count for 2026-07.

Is there a map of Arizona pumped storage hydro plants?

Yes — the map above. Each dot is one pumped storage hydro plant, sized by nameplate capacity and placed at the coordinates EIA files for it.

Which is the largest pumped storage hydro plant in Arizona?

Horse Mesa, at 131 MW. The table is sorted largest first, so the rest follow it.

Is there a pumped storage hydro plant near me in Arizona?

The county roll-up below groups every plant by county, which is the quickest way to find the one closest to a given town.

Which grid operator runs Arizona's pumped storage hydro plants?

No single ISO or RTO covers most of them. EIA files each plant against its own balancing authority, which in Arizona is largely a vertically integrated utility rather than an organised market.

How current is this, and what is left out?

EIA-860M for 2026-07. Hydroelectric pumped storage. Plants below 1 MW are not surveyed by EIA and so are absent; retirements and additions after 2026-07 arrive with the next monthly release.

Pumped Storage Hydro Plants in Arizona

Every operating pumped storage hydro plant in Arizona on EIA-860M for 2026-07: 3 plants, 10 generating units and 235 MW of nameplate capacity across 1 county.

As of 2026-07 (inventory dated 2026-07-31) · EIA-860M Preliminary Monthly Electric Generator Inventory · eia.gov/…/july_generator2026.xlsx · eia.gov/…/eia860m

Plants: 3; 10 generating units
Nameplate capacity: 235 MW
Counties: 1
Grid operator: Mixed; no single ISO covers a majority

Map of pumped storage hydro plants in Arizona

Every one of the 3 plants is drawn at the coordinate EIA files for it.

Loading map…

Pumped storage · 3

List of pumped storage hydro plants in Arizona

Sort by any column. Capacity is nameplate, summed across every generating unit EIA lists at the site.

pumped storage hydro plants in Arizona

Horse Mesa2 technologies	Salt River Project	Maricopa	131.3	4	1927	Operating
Mormon Flat2 technologies	Salt River Project	Maricopa	63.5	2	1926	Operating
WaddellHydroelectric Pumped Storage	Central Arizona Water Conservation Dist	Maricopa	40	4	1993	Operating

Largest pumped storage hydro plants in Arizona

1Horse MesaMaricopa County, Arizona131.3 MW
2Mormon FlatMaricopa County, Arizona63.5 MW
3WaddellMaricopa County, Arizona40 MW

Pumped storage hydro plants by county in Arizona

The county EIA files against each plant. It is the fastest way to find the plant nearest a given town.

County	Plants	Nameplate MW
Maricopa	3	234.8

Pumped Storage Hydro Plants in Arizona: FAQ

How many pumped storage hydro plants are in Arizona?: 3, with 235 MW of nameplate capacity between them, spread over 1 county. That is the EIA-860M operating count for 2026-07.
Is there a map of Arizona pumped storage hydro plants?: Yes — the map above. Each dot is one pumped storage hydro plant, sized by nameplate capacity and placed at the coordinates EIA files for it.
Which is the largest pumped storage hydro plant in Arizona?: Horse Mesa, at 131 MW. The table is sorted largest first, so the rest follow it.
Is there a pumped storage hydro plant near me in Arizona?: The county roll-up below groups every plant by county, which is the quickest way to find the one closest to a given town.
Which grid operator runs Arizona's pumped storage hydro plants?: No single ISO or RTO covers most of them. EIA files each plant against its own balancing authority, which in Arizona is largely a vertically integrated utility rather than an organised market.
How current is this, and what is left out?: EIA-860M for 2026-07. Hydroelectric pumped storage. Plants below 1 MW are not surveyed by EIA and so are absent; retirements and additions after 2026-07 arrive with the next monthly release.