General information

Waterway  Puyallup River
Current status   Active 
Type of facility Conventional Hydro
Mode of hydropower generation Run-of-river
Type of permit FERC Exemption

Ownership and operation

Owner Puget Sound Energy Inc
Owner type Investor-Owned Utility
Year first online (conventional hydro) 1904
Transmission or distribution system owner Puget Sound Energy Inc

Power and generating capacity

Number of units 4
Total capacity from hydraulic turbine-generator units within each plant 22.8 mW
Average annual net hydropower generation 93,347.1 mWH

The Electron Plant is a hydroelectric facility on the Puyallup River, near the town of Kopowsin, originally built by the Puget Sound Power Company from 1902-­1904. This company, along with the Electron Project, was later acquired by Puget Sound Traction, Light and Power Company in 1912. As discussed in more detail below, the Project has recently been purchased by Electron Hydro, LLC.

The Puyallup River originates in glaciers on Mt. Rainier and flows through the Mt. Rainier foothills and discharges into Commencement Bay in Puget Sound at the City of Tacoma. There are up to eight anadromous salmonid fish species in the Puyallup River, including Chinook, coho, chum, pink and sockeye salmon, steelhead, bull trout and sea-run cutthroat trout. There are also native resident salmonids, including rainbow and cutthroat trout, and mountain whitefish. Other native fish species include lamprey, minnows, sculpin, and sucker. Chinook, steelhead and bull trout are federally listed as threatened under the ESA. The Puyallup River has 26-­‐30 miles of stream habitat suitable for rearing juvenile fish upstream of the diversion and seasonal downstream fish passage is important to fish production in the river.

When the Project was originally constructed, there were no fish screens to keep fish out of the flow-line or out of the penstocks. As of 1998, there is downstream fish passage at the Project and it consists of a barrier net and trap-and-haul facility located in the storage reservoir’s forebay. This system captures migrating juvenile salmon that inadvertently enter the diversion flume. The upstream fish passage facility was constructed in 2000 and includes a concrete, 300-foot-long fish ladder adjacent to the wooden diversion dam opposite the flume intake. This system facilitates the upstream migration of spawning adult salmon and steelhead.

Because Electron was constructed in the early 1900s, it was never issued a license from the Federal Energy Regulatory Commission (FERC). Therefore, Electron is considered a “FERC exempt” project, which means that FERC does not consider the owner to be a hydropower licensee.