Boundary — Plant Summary
- EIA Plant ID
- 6433
- Capacity
- 1159.7 MW
- Primary Fuel
- Hydro
- Technology
- Conventional Hydroelectric
- Status
- Operating
- Location
- Pend Oreille, WA
- Operating Since
- 1967
- Generators
- 6
- Operator
- City of Seattle - (WA)
- Parent Company
- —
- Annual Generation
- 3,099,497 MWh
- Capacity Factor
- 30.4%
- Balancing Authority
- Seattle City Light
- ISO/RTO
- —
- NERC Region
- WECC
Boundary
OperatingHydro
Ranked #5 of 75 Hydro plants in WA#16 of 1454 nationally
1159.7 MW Hydro operating in Pend Oreille, WA — Seattle City Light
EIAGEMWD
1,159.7 MW
Nameplate Capacity
6
Generators
units
Conventional Hydroelectric
Technology
1967
Operating Since
Location
Ownership & Operator
Owner data does not fully agree across sources.
EIA typically reports the operating utility, while GEM resolves to the financial owner or parent corporation. Both can be correct.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | City of Seattle - (WA) | Seattle City Light | — |
| Owner(s) | City of Seattle - (WA) | Seattle City Light [100%] | — |
| Status | Operating | operating | — |
Ownership Chain
GEM identifies the owner as Seattle City Light [100%]
This entity is not yet in the GEM ownership database — chain unavailable.
About
Boundary Dam is a concrete arch gravity-type hydroelectric dam, finished in 1967, on the Pend Oreille River, in the U.S. state of Washington. The dam is located in the northeast corner of Washington state. It is operated by Seattle City Light and makes up a significant portion of the City of Seattle's energy portfolio. On average, it provides upwards of 46% of the power generated by Seattle City Light. Boundary Powerhouse, located adjacent to the dam, is completely built inside of the rock that makes up the left abutment of the dam itself. It has a nameplate capacity of just over 1 gigawatt of generation. The component of the hydroelectric project were listed on the National Register of Historic Places in 2018.
Read more on WikipediaThe Boundary hydroelectric plant is located in Pend Oreille County, Washington. It has a total capacity of 1159.7 MW across six generators and began operating in 1967. The primary fuel source is water. The plant is owned and operated by the City of Seattle - (WA). Boundary ranks as the 5th largest power plant in Washington out of 23, and 16th nationally out of 194 plants.
In the most recent year with available data, the plant generated 3,099,497 MWh of electricity, achieving a capacity factor of 30.4%. The balancing authority for the plant is Seattle City Light, and it operates within the Western Electricity Coordinating Council (WECC) NERC region.
Generated from EIA, GEM, and public data sources
Engineering & Generators
Grid Context
NERC Region
WECC
Balancing Authority
Seattle City Light
Grid Voltage
230 kV
Regulatory Status
RE
Entity Type
Municipal
Sector
Electric Utility
Generation
393.8K MWh
Latest Month
3.1M MWh
Annual Generation
30.4%
Capacity Factor
Jan 2023 – Dec 2025
Financial Data
No financial data available for this plant.
Pricing & Market Data
Market Position
LMP Node
BNDRYSCL_2_GEN51GNODE
Pricing Hub
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