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Project Summary

The Electron Hydropower Project is located on the Puyallup River in Pierce County, Washington. The Project begins about six miles west of Mt. Rainier National Park. Water is diverted from the river along a 10.2 mile wooden flume (topped with a railroad) to a forebay, then plunges 875 feet downhill through steel penstocks to the 26 megawatt Powerhouse. The project produces enough renewable energy to power about 30,000 homes.


Electron is a run-of-river project, there is no water storage from a large dam and reservoir like the big hydropower projects on the Columbia and Snake rivers. The upper Puyallup River is fed by direct precipitation and the melting snow and glacier fields of Mt. Rainier. This natural feature allows Electron to continue to generate clean power well through the summer with only a modest reduction in capacity by early Fall. Soon the November storms bring the project back up to full capacity again!


The project diverts up to 400 cubic feet of water per second (cfs), and must maintain minimum instream flows for all aquatic life living downstream in the river reach before diverted flow returns to the river from the Powerhouse. At times river flow substantially exceeds the project capacity, recently exceeding 10,000 cfs three different times within a thirteen month period! These mega-flows sweep over the diversion structure taking large boulders, cobble and sediment with them downstream. The project is being upgraded with a new 70 foot long by 12 foot diameter air bladder spillway to provide for this sediment transport while keeping these materials from entering the flume. This work began the summer of 2018. 

The Legacy of Electron

Electron was built in 1903 and still operates today. Its success is an incredible tribute to the engineers and builders who envisioned it so many years ago.

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Renewable Energy Production

As long as the skies rain and snow and water flows, hydro-power will be a renewable energy source. As a run-of-river diversion project Electron has a relatively low spatial impact, without massive river valley inundation, displacement of significant upland uses or loss of cultural or historical resources. The project does not stop sediment, woody debris or channel migration.  The project provides for basic fish passage and this program is in the design phase for further improvement. Electron has a small river footprint.


Unlike the Columbia and Snake river hydro-power projects, Electron does not rely on huge transmission systems to deliver power to the grid or customers a long distance away. Electron was originally built to serve Tacoma, located about twenty miles away. Now the Electron Heights substation is almost adjacent to the Powerhouse about one-quarter mile away. Electron is immediately connected to the power grid and therefore has a small transmission footprint.


The Electron Hydroelectric Project includes approximately 2200 acres of forest land and about ten miles of river frontage and riparian corridor. These lands support sustainable forestry, protect the river shoreline, provide diversified habitat for wildlife and maintain a scenic river corridor. Because the water delivery flume is located predominately on pile bents there is virtually zero land re-grading. This maintains a narrow flume corridor and is only slightly visible from the opposite hillside. Imagine what a road would look like if it were cutting across the hillside instead of the service train on top of the flume!  

Renewable energy made here!

Renewable energy made here!

Fish Passage Enhancement Program

The Electron Hydropower Project provides fish passage both upstream and downstream. The project includes a fish ladder and operation of a trap and haul facility that transports fish that were entrained in the flume downstream. The facility is managed by fisheries biologists and includes the counting, measuring and species identification of fish transported. This data gathering helps biologists estimate the productivity and eventual returns of salmon to the river in ensuing years. Electron is working to implement a new fish exclusion screen system at the intake that will prevent fish from entering the flume. The exclusion system will return fish to the river immediately below the Diversion. The first phase of this project was permitted and began Summer 2018 and is anticipated to take up to three years to fully implement. Upon completion, no fish will be able to enter the system thus eliminating the need for downstream trap and haul transport.


Electron Hydro, LLC works with the Puyallup Tribe to raise fish. Electron has helped to maintain Tribal rearing ponds upstream of the Project. Electron will build a new rearing pond on Ohop Creek for the Tribe to release Coho salmon. The project is awaiting permitting approval.


Electron will assist the Tribe in rebuilding two rearing ponds in 2019 specifically for Chinook salmon.  Electron will also build a Chinook rearing pond on its property in conjunction with the Phase II fish exclusion screens.

Wild Chinook salmon were listed in 1999 as Threatened under the Endangered Species Act. Chinook salmon are also the most preferred food for Orca whales. Orcas were listed as an Endangered species in 2005. Electron will help produce Chinook that will feed the Orca whales. The Puyallup River is well suited for this.

Fish being readied for tank truck transfer after counting, identifying and measuring

Fish being readied for tank truck transfer after counting, identifying and measuring