The US Army Corps of Engineers, Walla Walla District, in another stage of a $73 million project, has completed assembly on the second of three new advanced-designed hydroelectric turbines and begun its installation at Ice Harbor Lock and Dam, one of four dams on the lower Snake River.
These turbines “will be safer for fish, reduce maintenance costs and increase power generation efficiency by 3 to 4 percent,” said the Corps in a press release.
Final turbine and generator installations will take about 5 months with final commissioning scheduled for summer of 2022.
“The turbine is essentially the propeller that is rotated by water pressure to produce hydroelectric power,” said Project Manager Kevin Crum. “The adjustable blade turbine is fabricated with stainless steel blades that will resist corrosion and eliminate damage compared to the original carbon steel turbines. The new turbine units will utilize greaseless bushings and added improved seal technology to reduce infiltration into the river.”
The first of the 3 new turbines, a fixed blade turbine, was installed in Ice Harbor Dam in 2018. The second turbine, set into position on February 17, is an adjustable blade turbine runner that features adjustable turbine blades that can pass a wider range of water flow through the unit.
The original $73 million contract awarded to Voith Hydro Inc. included installing turbine replacements for three turbines — one fixed-blade runner and two adjustable blade runners – with the goal to improve the hydraulic flow conditions in the turbine water passageway. Field tests indicate significant hydraulic improvements to the flow conditions through the fixed blade turbine, and biological testing using balloon tagged fish in October 2019 resulted in a 98.25% direct survival rate.
The Corps anticipates the adjustable blade runner will have similar direct survival results when tests are conducted in the fall of 2022.
Ice Harbor Lock and Dam, located on the lower Snake River near Pasco, Washington, was constructed in the late 1950’s. Its first three hydro-turbine units were brought on-line in 1961 and three additional hydro-turbines became operational in 1976. Ice Harbor consists of the dam, powerhouse, spillway, navigation lock, two fish ladders, a removable spillway weir and a juvenile fish bypass facility.
“Ice Harbor Dam serves as a test bed for developing technical innovations aimed at raising survival rates of endangered and threatened fish in the region. Using an innovative design process to address fish survival, Ice Harbor Turbine replacement has become a model for future modernizations planned at McNary, John Day, and other Federal dams in the Northwest,” said Lt. Col Rick Childers, Commander of the Walla Walla District.
As the trio of 1961-vintage hydroelectric turbines approached the end of their design life, the Bonneville Power Administration and Walla Walla District recognized a window of opportunity to improve passage conditions for fish, said the press release.
“After 50 years of operation and increasing maintenance requirements, the need to replace the existing turbines at Ice Harbor presented the opportunity to pursue new turbine designs with fish passage improvement as a priority,” said Martin Ahmann, Hydraulic Engineer and Technical Lead for the turbine replacement project.
The Walla Walla District spearheaded an effort to partner federal agencies with the hydro-turbine industry to develop improved turbines designs. The design process combined Corps expertise in physical hydraulic modeling and fish passage, BPA economic expertise, and NOAA Fisheries’ knowledge of anadromous fish biology, with Voith Hydro Inc.’s industry expertise in designing large-scale hydro-turbines.
“The collaboration resulted in the fixed blade and adjustable blade turbines that improve hydraulic conditions for juvenile salmon and steelhead passing through the turbines,” says the press release.
“We are creating meaningful environmental and ecological improvements for these critical Northwest resources,” said Kevin Crum, Project Manager for the project.
— CBB, Jan. 30, 2020, TESTS OF NEW TURBINE AT ICE HARBOR DAM SHOWS IMPROVED FISH PASSAGE SURVIVAL https://www.cbbulletin.com/tests-of-new-turbine-at-ice-harbor-dam-shows-improved-fish-passage-survival/
— CBB, June 7, 2019, ‘ADVANCED-DESIGN’ HYDRO TURBINE INSTALLED AT ICE HARBOR DAM TO IMPROVE FISH PASSAGE, FUNDED BY BPA AT $92 MILLION https://www.cbbulletin.com/advanced-design-hydro-turbine-installed-at-ice-harbor-dam-to-improve-fish-passage-funded-by-bpa-at-92-million/