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.
EIA-reported nameplate capacity; other nameplate and seasonal ratings may differ.
Primary generation technology.
Pacific Gas & Electric Co. · Fresno County · CAISO
Battery subsystem rating.
Helms Pumped Storage is operating.
230 kV · Pacific Gas and Electric Company (PG&E)
Hydroelectric Pumped Storage
Helms Pumped Storage is operating.
230 kV · Pacific Gas and Electric Company (PG&E)
CAISO
Similar plants ranked by technology, capacity, and distance.
Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| 1 | 351 MW 404 MW summer | Hydroelectric Pumped Storage Water · PS | Jun 1984 | Operating |
| 2 | 351 MW 404 MW summer | Hydroelectric Pumped Storage Water · PS | Jun 1984 | Operating |
| 3 | 351 MW 404 MW summer | Hydroelectric Pumped Storage Water · PS | Jun 1984 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
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Project milestones and public references behind the asset profile.
EIA-860 lists generator 1, generator 2, generator 3 with this operating date.
CAISO · Fresno County
EIA-923 reports gross generation and net grid exchange for storage plants. Gross generation is shown as a discharge proxy; it is not a cycle count or conventional capacity factor.
| Largest reported plants | Capacity | State | |
|---|---|---|---|
| Diablo Canyon | 2,323 MW | CA | |
| Helms Pumped StorageCurrent | 1,053 MW | CA | |
| Colusa Generating Station | 712.4 MW | CA | |
| Gateway Generating Station | 619.7 MW | CA | |
| James B Black | 168.6 MW | CA | |
| Humboldt Bay | 167 MW | CA | |
| Poe | 142.8 MW | CA | |
| Pit 5 | 141.6 MW | CA |
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
View full reporting portfolioPG&E and Pacific Generation LLC filed a CPUC application proposing to transfer substantially all of PG&E's non-nuclear generation assets, including Helms, to Pacific Generation and later facilitate a sale of up to 49.9% of Pacific Generation's equity to minority investors. The proposal was not a completed acquisition or sale.
PG&E's proposed modernization focused on upgrading the three existing units rather than adding a fourth unit. The project was described as being in engineering and procurement, with each unit potentially gaining approximately 50-60 MW.
The California State Water Resources Control Board issued water-quality certification for relicensing of the Helms Pumped Storage Project.
Uprate construction was expected to begin with the first unit in 2029, with target construction or online milestones for the three units in 2029, 2030, and 2031. The proposed project could raise normal operating capacity from 1,212 MW to approximately 1,362-1,392 MW.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Helms Pumped Storage has a reported capacity of 1,053 MW. Source: EIA Form 860.
Helms Pumped Storage is a Hydroelectric Pumped Storage facility in Fresno County, CA, participating in the CAISO market.
Helms Pumped Storage is in Fresno County, CA, inside the CAISO balancing area.
Helms Pumped Storage is operated by Pacific Gas & Electric Co. according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Helms Pumped Storage reported 1,108.8 GWh over the twelve months to 2026-06. For a storage plant this is reported gross generation — a discharge proxy, not a cycle count or a conventional capacity factor.
Helms Pumped Storage interconnects at Gregg Substation (non-Project receiving/interconnecting substation), on the Pacific Gas and Electric Company (PG&E) system.
By capacity, Helms Pumped Storage ranks #8 of 39 operating plants of the same technology nationally. It ranks #2 of 7 in CA.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.
