PNNL

Abstract

Hydropower is a crucial renewable energy source with numerous advantages beyond being a clean energy option. The Federal Columbia River Power System accounts for 28% of hydropower capacity in the U.S., and its 90 large Kaplan turbines are being planned for replacement with the primary goal of improved fish passage (IFP) and reducing fish injury, starting with Ice Harbor Dam. In 2019, a one-of-a-kind stainless steel IFP fixed-blade runner, optimized for both improved fish passage and power efficiency, was installed in Ice Harbor’s Unit 2. Over two decades of research guided the design to benefit juvenile salmon. The new Unit 2 turbine water passageway was characterized at three operating points set around a 1% drop from peak power generation efficiency—Lower 1% (lower discharge than peak efficiency), Peak Efficiency, and Upper 1% (higher discharge than peak efficiency)—using autonomous Sensor Fish technology. Nadir pressures below 101.7 kPa (atmospheric pressure) near the runner can negatively affect certain fish species, such as salmonids, with increasing effects at nadir pressures below 86.2 kPa dependent upon a fish’s migration depth and acclimation pressure (i.e., gas volume in the swim bladder). For the new Unit 2 Upper 1% operating point, 0% and 0.9% of nadir pressures were lower than 86.2 kPa and 101.7 kPa, respectively, compared to 19.2% and 35.3% for the baseline turbine. Furthermore, the percentage of datasets with acceleration events (= 95g) was significantly reduced at the turbine runner for the Lower 1% and Peak Efficiency operating points. In conclusion, the new IFP fixed-blade turbine successfully achieved the primary design objective of enhancing fish survival while improving power generation efficiency by approximately 4%. This innovation demonstrates a commitment to preserving aquatic ecosystems while harnessing the full potential of hydropower as a renewable energy source.