Preliminary testing on a new turbine installed by Voith at the Ice Harbor Dam on the Snake River in Washington state, US, shows the new design has achieved a survival rate of 98.25% for Chinook salmon passing through the turbine - a significant improvement over similarly sized conventional Kaplan turbine installations which typically see survival rates in the low 90 percent range, says Voith.
One of the primary goals of the new Unit 2 turbine design was to improve the fish passage survival rate, and this was accomplished while simultaneously increasing the turbine’s hydraulic performance and extending the life cycle of the unit. Voith says the turbine achieved a 4% boost in hydraulic efficiency.
The success of the updated design was the result of collaboration between Voith, the United States Army Corps of Engineers (USACE), the National Marine Fisheries Service (NMFS) and the Bonneville Power Administration (BPA).
“This was a truly collaborative effort between BPA, USACE, NMFS and Voith,” explained Stanley Kocon, President and CEO, Voith Hydro North America. “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. 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.”
The testing was conducted in late 2019 with the Voith-manufactured turbine that had been installed earlier that summer. To perform the test, the Pacific Northwest National Laboratory (PNNL) released “sensor fish” devices within the turbine intakes to collect pressure and acceleration data during operation.
Also part of the testing was the release of live juvenile Chinook salmon equipped with balloon-tags to aide in the recovery process. After release, each fish was then examined following passage downstream through the turbine.
Analysis of the preliminary results of these tests showed a high rate of direct survival for migrating juvenile salmonids as they passed through Unit 2, satisfying a key goal of the modernization project.
Designing and manufacturing the turbine
For Voith, the project began in 2010 when the manufacturer was awarded the contract by USACE. After a multi-year design period, manufacturing at its Pennsylvania facility began. Installation and commissioning on the propeller turbine was complete in the summer of 2019.
“The collaboration involved in this project is what made it succeed,” said Jason Foust, Hydraulic Design Engineer, Voith Hydro North America. “Utilizing a combination of detailed numerical simulations, physical model testing, and decades of hydro turbine experience, we created one of the most advanced turbines installed anywhere in the world right now for improving direct survival. All of our tools and knowledge were focused on achieving a high survival rate for migrating fish. 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, making this project an incredible success.”
Another Voith turbine, a Kaplan with adjustable blades designed by the same team using the same fish-passage evaluation process, is currently being installed at the site, and is expected to undergo similar testing once it is commissioned.
Ice Harbor is located about eight miles northeast of Burbank, Washington, and is one of four dams on the Lower Snake River under USACE 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. Ice Harbor Dam is a concrete gravity run-of-river renewable energy facility that began operation in 1962 and has a generating capacity of 603MW.
Photo Credit Andrea Starr Pacific Northwest National Laboratory