Salmon move up the Humber river attracts spectators near the Old Mill subway station in Etobicoke ... [+]
NurPhoto via Getty ImagesResearchers from Cornell University published a study in Nature on the adverse ecological effects of hydropower dams. The study examines how these dams block the flow of water, creating large inundated reservoirs of water conducive to the production of methane gas, a key factor of climate change among the greenhouse gases.
But hydropower plants also affect the migration of fish. According to NOAA Fisheries, in the US, more than two million dams and other obstacles block fish from migrating each year. Reduced fish populations affect the entire ecosystem in rivers and streams.
In reservoirs created by large, channel-spanning dams, it can be nearly impossible for certain types of fish like juvenile salmon, which rely on actively flowing water to drift downstream to the ocean to make the journey successfully. According to NOAA Fisheries, the last remaining populations of Atlantic salmon in US waters exist in a few rivers and streams in central and eastern Maine.
A California-based renewable energy company that makes sustainable hydropower solutions, Natal Energy says that it has created technology that eliminates the need for large, channel-spanning dams. Natel Energy has raised $45.8M to date.
The female CEO and co-founder Gia Schneider says their technology works with low drops - five to 30 feet instead of the high dams - 100-900 feet - needed for conventional turbines.
Schneider says the company's restoration hydro turbine technology is fish-safe in several ways because it enables river restoration elements to be incorporated into the hydropower plant design and the blade design is designed with fish in mind.
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"The turbines inside hydropower plants can injure or kill fish that physically pass through them by striking them or by creating a sudden change in pressure — think what would happen to a human in an airplane flying at 30,000 feet if it were to lose cabin pressure suddenly," said Schneider. "The cumulative effects of both turbines that are not fish-friendly and of large dams can be quite severe."
"The blades in our turbine have a [..] unique shape that makes them somewhat like an airbag if fish hit them - the fish are deflected around the blade, as opposed to being struck sharply in a manner that results in cuts, abrasions, breaks, or other injuries," said Schneider. "And, compared to conventional turbines, our turbines have fewer blades, which reduces the chance that a fish hits a blade when passing through the turbine."
Schneider says their fish safe solutions make it easier for fish to travel up and downstream around the hydropower plants; and virtually eliminates the chance of injury for fish that do end up passing through a turbine in the powerhouse.
Natal's more fish-friendly blades are optimized for low head between 6.5 and 33 feet, which the company says eliminates the need for fine fish screens.
Natel Energy works with several fish biologists from the Pacific Northwest National Laboratory (PNNL), experts in hydro turbines and fish passage. Daniel Deng leads PNNL's Bio-Acoustics and Flow Lab. The company also partnered with Alden Laboratory to research how fish were affected by turbine blades, published in the Journal of Ecohydraulics in December 2019, which came down to blade slant and edge thickness.
The Link LonkNovember 24, 2020 at 01:40AM
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This New Fish-Friendly Technology Was Designed With Fish In Mind - Forbes
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