Preliminary testing shows a survival rate of 98.25% for fish passing through the new turbine installed at the 603-MW Ice Harbor powerhouse on the Snake River in Washington State.
According to Voith Hydro, which designed the turbine, this is a significant improvement over similarly sized conventional Kaplan turbine installations, which typically see survival rates in the low 90% range.
One of the primary goals of the new Unit 2 turbine design was to improve the fish passage survival rate.
Ice Harbor, which began operating in 1962, is located about 8 miles northeast of Burbank, Wash., and is one of four dams and hydropower plants on the Lower Snake River under U.S. Army Corps of Engineers operation. Improving the fish passage rates at each dam is a critical need as it allows more juvenile fish to migrate downstream after hatching while also maintaining the high renewable energy generation capabilities for the region.
Stanley Kocon, president and chief executive officer of Voith Hydro North America, says this was a collaborative effort between the Bonneville Power Administration, Corps, National Marine Fisheries Service and Voith. “Together, this team looked at the results of the modeling and designed a propeller turbine based on what was safest for the Snake River’s chinook salmon fish population,” he said. “This is a significant step in protecting this and other species, such as steelhead, while also continuing to serve the renewable electricity needs of the Pacific Northwest.”
Voith was awarded the contract to manufacture this turbine in 2010. After a multi-year design period, installation and commissioning on the propeller turbine was complete in the summer of 2019.
“All of our tools and knowledge were focused on achieving a high survival rate for migrating fish,” said Jason Foust, hydraulic design engineer with Voith Hydro North America. “We weren’t willing to compromise on any aspect of fish passage, and that meant that we had to develop innovative solutions. Through the process, we also boosted the turbine’s hydraulic efficiency, improved cavitation behavior and increased the turbine life cycle.”
The testing was conducted in late 2019. The Pacific Northwest National Laboratory (PNNL) released “sensor fish” devices within the turbine intakes to collect pressure and acceleration data during operation. Another part of the testing was the release of live juvenile chinook salmon equipped with balloon tags. Each fish was released, allowed to pass downstream through the turbine, and then collected for examination.
Another Voith turbine, a Kaplan with adjustable blades designed using the same fish-passage evaluation process, is being installed at the site and is expected to undergo similar testing once it is commissioned.
The Voith Group is a global technology company. The Group Division Voith Hydro is a full-line supplier and partner for equipping hydropower plants.