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, such as tidal, geothermal and biomass, resources that are located close to home in Western Washington.

“This region is blessed with an abundance of carbon-free natural energy sources,” said PUD General Manager, Steve Klein. “It makes sense to tap the solar intensity of the sun, the continuous hydrological cycle that produces flowing rivers and streams, the strong and unrelenting wave and tidal force and the virtual limitless heat of the earth’s core, all of which can provide clean renewable energy to serve the needs of our community.” 

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 it expects will generate up to 3 average megawatts – or enough power for about 2,000 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, above natural impassible barriers so as not to affect migrating fish populations. These “backyard resources” also reduce the need for hundreds of miles of new transmission line, minimizing both line losses and environmental impacts.

Small-Hydro Potential

Snohomish PUD is assessing several additional small-hydropower sites for potential development in the next five to 10 years. The projects’ generating potential ranges anywhere from 2 to 25 megawatts. If fully developed, the collective energy output could serve tens of thousands of Snohomish PUD customers.

Youngs Creek HydroThe utility has met with a broad range of stakeholders – including local tribes, environmental groups and regulatory agencies – to share its plans. It has worked closely with the Washington Department of Fish & Wildlife to ensure the Youngs Creek facility provides adequate levels of river flow and protects fish.

“In assessing potential sites, we’re especially mindful of anadromous fish populations, hydrology, geology, environmental issues and access to existing roads and transmission lines,” said PUD Assistant General Manager of Water and Generation Kim Moore. “We want 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.

New small-hydropower sites will require approval by the Federal Energy Regulatory Commission. The utility expects each project will take three to five years from the application stage to completion of construction.

The small-hydro facilities don’t currently qualify under Washington’s renewable portfolio standard (RPS), although a state bill last year proposed including new hydro projects of 5 average megawatts or less. It didn’t pass. Snohomish PUD and other utilities have supported such legislation. Under its RPS, Oregon allows new hydro projects up to 50 megawatts if they obtain low-impact certification.

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 potential load growth of 25 percent by 2020. Its service area is expected to reach nearly 1 million residents in the next 15 years.

Snohomish PUD is pursuing a broad range of renewable energy resources. It has secured contracts for wind energy from three facilities in Washington and Oregon. Two local cogeneration facilities supply renewable energy using wood-waste. In addition, in 2009 the utility launched a comprehensive solar program to install demonstration projects in the community and offer resources to customers interested in installing their own systems. The PUD also has emerged as a leader in tidal and geothermal energy research, with $2.7 million in federal funding secured to date for these green initiatives.

Benefits of Small Hydropower

  • Typically located outside sensitive wilderness areas
  • Sited above or near natural barriers to negate impact on migrating 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