# Helms Pumped Storage

CAISO asset profile · https://askthegrid.com/assets/facilities/helms-pumped-storage

Pacific Gas & Electric Company · Fresno County · CAISO

Helms Pumped Storage is a battery energy storage facility with 1,053 MW of EIA-reported nameplate capacity in Fresno County, California, registered as EIA Plant ID 6100. Pacific Gas & Electric Co. owns and operates the plant. The facility interconnects at Gregg Substation (non-Project receiving/interconnecting substation) at 230 kV.

## Profile

- **Grid role:** Pumped-storage energy-storage and grid-balancing resource: it pumps during lower-demand or lower-price periods and generates during peak demand, providing quick-load-on capability and supporting grid stabilization.
- **Grid connection:** Gregg Substation (non-Project receiving/interconnecting substation) · 230 kV · Pacific Gas and Electric Company (PG&E).

## Metrics

- **Reported capacity:** 1,053 MW — EIA-reported nameplate capacity; other nameplate and seasonal ratings may differ.
- **Technology:** Hydroelectric Pumped Storage — Primary generation technology.
- **Registry anchor:** Plant 6100 — Pacific Gas & Electric Co. · Fresno County · CAISO
- **Storage duration:** 6 hours — Battery subsystem rating.
- **Operating status:** Operating — Helms Pumped Storage is operating.
- **Grid connection:** Gregg Substation (non-Project receiving/interconnecting substation) — 230 kV · Pacific Gas and Electric Company (PG&E)

## Facts

- **Reported capacity:** 1,053 MW — Hydroelectric Pumped Storage · confidence: high
- **Operating status:** operating — Helms Pumped Storage is operating. · confidence: medium
- **Interconnection:** Gregg Substation (non-Project receiving/interconnecting substation) — 230 kV · Pacific Gas and Electric Company (PG&E) · confidence: medium
- **Location:** Fresno County — CAISO · confidence: high
- **Operator:** Pacific Gas & Electric Co. · confidence: high
- **Asset role:** hydroelectric — CAISO · Fresno County

## Related parties

- **Operator:** Pacific Gas & Electric Company — Owner / developer associated with Helms Pumped Storage. ([source](https://www.pge.com/))

## Sources

- [The History of Helms, PG&E’s Underground Power Plant | PG&E](https://www.pge.com/en/newsroom/currents/future-of-energy/the-history-of-helms--pg-e-s-underground-power-plant.html) — pge.com · other — The History of Helms, PG&E’s Underground Power Plant Hidden in a granite cavern deep within California’s Sierra Nevada mountains sits the Helms Pumped Storage Power Plant. This hydroelectric marvel generates over 1,200 megawatts of power, helping to stabilize the grid during peak demand periods.
- [PG&E Celebrates 40th Anniversary of Helms Pumped Storage Power Plant | PG&E](https://www.pge.com/en/newsroom/currents/future-of-energy/articles-4039-pge-celebrates-40th-anniversary-helms-pumped-storage-power-plant.html) — pge.com · other — PG&E Celebrates 40th Anniversary of Helms Pumped Storage Power Plant Since 1984, Helms’s 1,212 MW underground pump-generator powerhouse, switchyard, and 61 miles of 230 kV transmission line has delivered safe, reliable, clean, and affordable hydropower to our customers and hometowns.

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Canonical page: https://askthegrid.com/assets/facilities/helms-pumped-storage
Website: [Pacific Gas & Electric Company](https://www.pge.com/)

Source: Ask the Grid — https://askthegrid.com/