South Fork Tolt
Hydro power plant in King County, Washington. 16.8 MW of nameplate capacity across 1 generator, operated by City of Seattle - (WA).
Also known as South Fork Tolt Power Plant · EIA plant 622
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 16.8 MWNameplate
- Generators
- 1 operatingEIA-860M, August 2026
- Operating since
- November 1995First generator online
- Operator
- City of Seattle - (WA)EIA operator ID 16868
- Grid
- SCLBalancing authority SCL
- Price nodes
- 1 CAISO nodeResource nodes with prices
- Location
- King County, WA47.6992, −121.7833
- EIA plant ID
- 622EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power South Fork Tolt produces
Free · EIA-923Net generation, 2025
48.6 GWh
48,580 MWh, final
Capacity factor, 2025
33.0%
2024: 30.2%
January to July 2026
Not reported
Provisional. 0 of 7 months reported
Range, 2015 to 2025
29.3–58.5
GWh a year. Low 2019, high 2022
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | 43,733 | Not reported | 12 of 12 |
| 2001 | 39,697 | Not reported | 12 of 12 |
| 2002 | 77,866 | Not reported | 12 of 12 |
| 2003 | 48,674 | Not reported | 12 of 12 |
| 2004 | 60,443 | Not reported | 12 of 12 |
| 2005 | 44,789 | Not reported | 12 of 12 |
| 2006 | 53,528 | Not reported | 12 of 12 |
| 2007 | 55,798 | Not reported | 12 of 12 |
| 2008 | 57,101 | Not reported | 12 of 12 |
| 2009 | 50,468 | Not reported | 12 of 12 |
| 2010 | 53,774 | 36.5% | 12 of 12 |
| 2011 | 49,762 | 33.8% | 12 of 12 |
| 2012 | 62,991 | 42.7% | 12 of 12 |
| 2013 | 55,304 | 37.6% | 12 of 12 |
| 2014 | 63,313 | 43.0% | 12 of 12 |
| 2015 | 48,847 | 33.2% | 12 of 12 |
| 2016 | 52,101 | 35.3% | 12 of 12 |
| 2017 | 54,544 | 37.1% | 12 of 12 |
| 2018 | 58,268 | 39.6% | 12 of 12 |
| 2019 | 29,293 | 19.9% | 12 of 12 |
| 2020 | 41,978 | 28.4% | 12 of 12 |
| 2021 | 54,388 | 37.0% | 12 of 12 |
| 2022 | 58,475 | 39.7% | 12 of 12 |
| 2023 | 30,125 | 20.5% | 12 of 12 |
| 2024 | 44,630 | 30.2% | 12 of 12 |
| 2025 | 48,580 | 33.0% | 12 of 12 |
| 2026 (provisional, partial year) | Not reported | Not reported | 0 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free account · CAISOEmissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024. Plants without steam cooling, such as wind, solar and batteries, do not report cooling water.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| 1 | Conventional Hydroelectric | 16.8 | November 1995 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists City of Seattle - (WA) as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
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Power plants near South Fork Tolt
More plants operated by City of Seattle - (WA)
Questions about South Fork Tolt
How much power does South Fork Tolt produce?
South Fork Tolt reported 48,580 MWh (48.6 GWh) of net generation in 2025, a 33.0% capacity factor on 16.8 MW of nameplate capacity.
Where is South Fork Tolt?
South Fork Tolt is in King County, Washington, at 47.6992, −121.7833. It is in the Seattle City Light balancing area (SCL).
Who operates South Fork Tolt?
EIA-860M for August 2026 lists City of Seattle - (WA) as the operator (EIA operator ID 16868). The operator is not always the owner.
When did South Fork Tolt start operating?
Its first generator began operating in November 1995, according to EIA-860M.
Does InfraMap have power prices for South Fork Tolt?
Yes. InfraMap has CAISO day-ahead and real-time prices at 1 price node linked to South Fork Tolt, with the hub price and node-to-hub basis. Prices are free with an InfraMap account; pricing node names are part of InfraMap Pro.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
- CAISO day-ahead and real-time prices; node and hub assignments as of 2026-10-05
- Plant names from OpenStreetMap, © OpenStreetMap contributors (ODbL)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page