Hemmingway BESS — Plant Summary
- EIA Plant ID
- 66325
- Capacity
- 166 MW
- Primary Fuel
- Battery Storage
- Technology
- Batteries
- Status
- Operating
- Location
- Owyhee, ID
- Operating Since
- 2025
- Generators
- 3
- Operator
- Idaho Power Co
- Parent Company
- IDACORP
- Annual Generation
- -6,501 MWh
- Capacity Factor
- -0.5%
- Balancing Authority
- Idaho Power Company
- ISO/RTO
- —
- NERC Region
- WECC
Hemmingway BESS
OperatingBESS
Ranked #1 of 10 BESS plants in ID#224 of 837 nationally
166 MW BESS operating in Owyhee, ID — Idaho Power Company
EIA
166 MW
Nameplate Capacity
3
Generators
units
Batteries
Technology
2025
Operating Since
Location
Coordinates
43.3515, -116.6609
County
Owyhee, ID
Nearby Plants
- Melba BESSBESS2 MW · 8.4 km
- Mora Drop Hydroelectric ProjectHydro1.7 MW · 19.4 km
- Murphy Flat SolarSolar20 MW · 23.4 km
Ownership & Operator
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Idaho Power Co | Idaho Power | — |
| Owner(s) | Idaho Power Co | IDACORP | — |
| Status | Operating | — | — |
Ownership Chain
About
Hemingway BESS is a battery energy storage system located in Owyhee County, Idaho. The plant has a total capacity of 166 MW and is comprised of 3 generators utilizing battery technology. It is owned by IDACORP and operated by Idaho Power Co. The plant began operating in 2025.
Hemingway BESS is the largest of 3 battery storage plants in Idaho, and ranks 362nd out of 514 such plants nationally. The facility has a storage duration of 4 hours. The plant operates within the Idaho Power Company balancing authority, and is located within the Western Electricity Coordinating Council (WECC) NERC region. The plant's primary fuel is listed as MWH, indicating it draws power from the grid to charge its batteries.
Generated from EIA, GEM, and public data sources
Engineering & Generators
Grid Context
NERC Region
WECC
Balancing Authority
Idaho Power Company
Grid Voltage
34.5 kV
Regulatory Status
RE
Entity Type
Investor-Owned Utility
Sector
Electric Utility
Generation
−213 MWh
Net Charging
-6.5K MWh
Annual Net Energy
-0.5%
Capacity Factor
Positive values indicate net discharge (generation exceeds station load). Negative values indicate net charging. Pure battery storage plants are typically net negative due to round-trip efficiency losses.
Financial Data
No financial data available for this plant.
Pricing & Market Data
This plant is outside organized wholesale electricity markets (ISOs/RTOs). Nodal pricing data is not available.
News & Articles (7)Beta
Regulatory·permitting
Idaho Power Company; Notice of Intent To File License Application, Filing of Pre-Application Document, and Approving Use of the Traditional Licensing Process
Federal Register (FERC)·3 days ago
Industry·corporate
US investor-owned utilities in Idaho, New Mexico seek to add energy storage, solar PV
Idaho Power's 2025 integrated resource plan (IRP) includes three times as much solar, wind and energy storage as new gas generation.
Idaho Power (operator)
Energy-Storage.News·8 months ago
Industry·commissioning
Prevalon brings 80-MW battery storage online for Idaho Power
Idaho Power could add an additional 705 MW of storage in the next four years, per its draft integrated resource plan.
Prevalon (other)Idaho Power (operator)
Utility Dive·9 months ago
General
Idaho Power seeks regulatory approval of 100MW additional BESS after offtake agreement with Savion falls through
Idaho Power is seeking approval from the state regulator to deploy an additional 100MW of BESS to plug the gap left within its portfolio.
Energy-Storage.News·1 years ago
Last updated 2026-03-25
View all 7 articles