Snohomish County Public Utility District No. 1

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Small Hydropower

Woods Creek ProjectFor Snohomish County PUD, drawing energy from local waterways is a natural fit. The rapidly growing public utility has moved aggressively on several fronts to research and develop clean energy resources that are located close to home in Western Washington.

The Pacific Northwest offers an abundance of carbon-free natural energy sources.  So it makes sense to tap the solar intensity of the sun, the continuous hydrological cycle that produces flowing rivers and streams, the strong and the virtual limitless heat of the earth’s core. All of these resources can provide clean renewable energy to serve community needs. 

In 2009, the utility acquired two sites near Sultan, WA, for small-hydropower generation. The PUD purchased and renovated a small-hydro project at Woods Creek, which provides enough energy for several hundred homes. Upgrades to turbines have increased the project’s output by nearly 25 percent. The utility also has installed new tailrace and self-cleaning intake screens to reduce debris build up and protect resident fish populations.

In late 2011, the utility began operating its second small-hydro project, Youngs Creek, which generates up to 3 average megawatts – or enough power for about 3,000 homes. At full capacity (7.5 MW), it would provide enough power for 7,500 homes. Both sites offer attractive characteristics. They’re located outside of sensitive areas, such as designated wilderness lands, and in the upper reaches of creeks, at or above natural impassible barriers so as not to affect migratory fish populations. These “backyard resources” also reduce the need for hundreds of miles of new transmission line, minimizing both line losses and environmental impacts.

In 2018, the PUD officially powered up a pair of new small hydropower projects in the foothills above North Bend. Located above an impassable fish barrier and designed in a similar fashion to the Youngs Creek project, the PUD’s Hancock Creek and Calligan Creek Hydroelectric Projects will provide enough clean, renewable energy combined to power about 12,000 homes at full capacity (up to 6,000 homes at average MW generation).

Developing Small-Hydro

Youngs Creek HydroWhen assessing potential sites, the PUD was especially mindful of anadromous fish populations, hydrology, geology, environmental issues and access to existing roads and transmission lines. It aimed to balance energy generation with the need to protect river flows, water quality and cultural resources.

The PUD small-hydropower facilities are designed as run-of-the–river projects, which divert a portion of the water to a pressurized pipeline that delivers it to a turbine downstream for energy production. Given rainfall patterns in the region, the generating output is naturally maximized during times of high energy demand. It also complements other intermittent energy sources, such as wind and solar.

The new small-hydropower sites required approval by the Federal Energy Regulatory Commission. 

The small-hydro facilities generally don’t currently qualify under Washington’s Energy Independence Act (I-937).

For Snohomish, the push for more locally generated green energy resources is less about state mandates and more about creating a diverse, carbon-free energy supply. Its Board of Commissioners has made a commitment to meeting growing energy needs through cost-effective conservation and renewable energy resources. The utility faces continued load growth in the coming decades as the region grows.

Benefits of Small Hydropower

  • Carbon-free resource
  • Typically located outside sensitive wilderness areas
  • Sited above or near natural barriers to negate impact on migratory fish
  • Negligible impact on oxygen levels, river temperatures and flow rates
  • Non-polluting resource with no heat or noxious gas releases
  • A proven technology, competitive in price to other green resources
  • Complements intermittent energy sources, such as wind and solar
  • Generates green jobs in engineering and construction
  • Hydropower facilities have long lives, up to 100 years or more