Hydropower

Hydroelectric Turbine Designed to Pass Fish

Testing has started on a new hydropower turbine that is designed to provide safer downstream passage for migrating fish while generating power almost as efficiently as existing turbines.

WASHINGTON, DC, US, 2001-09-28 [SolarAccess.com] Biologists and engineers at Alden Research Laboratory will test a three-bladed corkscrew turbine in a new facility that has been set up in Holden, Massachusetts. The design was developed by Alden Labs and Concepts NREC, located in Woburn, with support from the U.S. Department of Energy and the hydroelectric industry’s Hydropower Research Foundation. The design has three wrapped blades around a central hub in a corkscrew shape, compared with up to ten blades in a conventional turbine. The elongated blades compensate for the smaller number to extract energy from the water. The blade geometry gradually reduces the pressure and minimizes sudden changes in flow velocity, which could injure fish. The facility will allow fish to swim through a closed-loop piping system of 85 feet, past a one-third-scale pilot turbine and into a 24,000 gallon tank. Testing will involve rainbow trout until spring; next fall, Alden will test seven other species including smallmouth or largemouth bass; golden shiner; American eel; Chinook or Coho salmon; American shad; shortnose, lake, or white sturgeon; and white sucker. Existing turbines pass between 85 to 95 percent of fish, but the Advanced Hydropower Turbine Systems program seeks to boost that level to 98 to 100 percent survival. Dam operators lose power when they are required to spill water through gates or bypass reaches, rather than through turbines, and the hydroelectric industry says higher fish survival would achieve the goals of both fishery and power generation industries. The AHTS turbine program originated at the urging of the U.S. hydro industry to optimize fish protection measures while maintaining valuable energy production. The program is intended to fashion a new turbine design based on the needs of fish, and then to modify existing turbines for improved fish passage. Now in its sixth year, the program has received US$16.6 million in federal funding, which the industry complains is a fraction of the total budget for renewable energy in that country. The Alden turbine cost $7 million in combined government and industry funds. The U.S. industry is concerned that funding for the program could be seriously jeopardized if Congress does not adopt stronger funding levels proposed by the Senate. The Senate wants $9.3 million for hydropower research, compared with $2 million suggested by Congress. DOE has identified 29,780 MW of potential hydroelectric capacity at existing dams, and the new turbine could increase that level by replacing existing turbines. The National Hydropower Association estimates that better fish diversion near main turbines could double that potential to 70,000 MW, at a cost comparable to existing hydraulic turbines. Hydropower generates 10 percent of U.S. electricity, and 80 percent of total output from renewable energy facilities.