Eels keep dying in hydro dam turbines.
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Eels → die → turbines
A new design could change that
Also: Why an airship was spotted in the skies over Alberta
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airship → change → Alberta
Welcome to our weekly newsletter where we highlight environmental trends and solutions that are moving us to a more sustainable world.
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that → welcome → world
When we came across this story about eels dying in droves at hydro dams, our first thought was: if this was birds and windmills, there'd be an uproar.
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this → come → dams
Our slippery friends deserve to navigate their waterways safely.
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friends → deserve → waterways
Here's a company that's working on a tech solution to this problem.
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that → work → problem
This week:
- Eels keep dying in hydro dam turbines.
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Eels → die → turbines
A new design could change that
- The Big Picture: How a heat pump works
- Why an airship was spotted hovering over this central Alberta town
Eels keep dying in hydro dam turbines.
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Eels → change → turbines
A new design could change that
American eels have to pass through the blades of hydropower plant turbines as they migrate down the St. Lawrence River, a perilous journey that has only a 74 per cent survival rate at one power plant.
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that → change → plant
New turbine runners could change that, Natal Energy says.
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Energy → change → that
Every year, thousands of endangered American eels swim down the St. Lawrence River on their way to their breeding grounds in the Sargasso Sea in the Caribbean.
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thousands → swim → Caribbean
But many of them are struck and killed by the turbine blades of the hydroelectric dams spanning the river, one factor contributing to a 99 per cent population decline in the area since the 1970s.
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many → strike → 1970s
Researchers at Natel Energy, a California startup specializing in fish-friendly turbines, say they’ve designed a turbine runner that would stop those fatalities — without sacrificing power generation efficiency.
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that → specialize → efficiency
“For many decades, people thought that if you were going to protect fish, you're going to lose power, or you're going to incur some large civil work expenditure,” Kate Stirr, Natal Energy's vice-president of external affairs, told CBC News.
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Stirr → think → News
“What's illustrated by [our] study is that there's no trade-off between power generation and fish survival that's necessary to make.”
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that → illustrate → generation
Why declining eels are a big deal
American eels are Canada’s only true catadromous species, meaning they’re born in the ocean, then swim upstream to spend their adult lives in freshwater locations like Lake Ontario, sometimes for up to 20 years.
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they → decline → years
Finally, after growing sometimes over a metre in length, they swim back out to the ocean to spawn.
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they → grow → ocean
Seen as a key indicator of the biodiversity of the region, the eel has also long been important and even sacred to Indigenous people along Lake Ontario and the St. Lawrence and Ottawa rivers.
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eel → see → Ontario
And although they’ve historically been abundant in Lake Ontario, their numbers have plummeted due to overfishing, habitat loss and hydroelectric dams.
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numbers → plummet → overfishing
By the late 2010s, just 18,000 passed through fish ladders at the Moses-Saunders Power Dam each year on average, down from a million in the '80s.
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18,000 → pass → 80s
As all of the American eels in the St. Lawrence River basin are breeding females, their migration downstream is important for the success of the overall species.
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migration → breed → species
Commercial fishing of eels was banned in Ontario in 2004, and various programs have attempted to combat population drops, such as one funded by Ontario Power Generation paying fishermen to trap live eels and transfer them down the river to bypass hydro plants.
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programs → ban → plants
Testing in the late '90s found that more than a third of the eels trying to migrate downstream were killed by hydroelectric dams on the St. Lawrence River, with turbines at the Moses-Saunders Dam alone killing roughly 26 per cent of the eels that passed through.
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that → find → eels
The dam provides power to both the U.S. and Ontario, and is one of two mainstem hydroelectric plants on the St. Lawrence that eels must survive to reach the ocean.
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eels → provide → ocean
A less deadly turbine
Natel's new “FishSafe” turbine design features a more curved blade shape and a “thick, blunt leading edge” instead of a thin one, providing a more glancing blow that reduces the chance of injury if a fish is struck by the rotating blades.
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fish → feature → blades
It also minimizes the gap between the blade and its housing to lower the chance of fish getting trapped.
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fish → minimize → chance
A computer simulation of turbines on the U.S. side of the Moses-Saunders dam found the new design could raise the survival rate of American eels passing through to 98 per cent.
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design → find → cent
The eels in the St. Lawrence River basin are overwhelmingly breeding females, making their survival important to the overall species (Stephany Hildebrand)
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survival → breed → species
The new blade design also demonstrated a comparable efficiency as existing ones, and can be installed without costly full-system overhauls in most cases.
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design → demonstrate → cases
“If we can have a solution where the runner just is an in-place upgrade, then it makes it very easy for the owner to think about a solution that protects fish in addition to modernizing their plant,” Stirr said.
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Stirr → have → plant
A lot of the existing hydropower plants in North America and in Europe are decades old, she said.
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she → exist → Europe
Natel Energy is hoping that its new proof-of-concept will show hydro dam companies that prioritizing fish survival won’t cut into their bottom line, and convince more to come on board.
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prioritizing → hop → board
She said the firm has been in conversation with Canadian companies, and recently installed some of its turbine runners at a plant in France that was subject to regulations protecting European eels.
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that → say → eels
The turbines have since been successfully tested with live eels.
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turbines → test → eels
“We love eels, and I would say that this technology, we hope, can really be a game-changer for the American eel population.”
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we → love → population
In our latest episode: Alberta has the country on tenterhooks as the province votes on whether to consider splitting from Canada.
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province → have → Canada
At least one separatist leader says the threat to leave is serving as leverage for the oil industry.
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threat → say → industry
Others in the province say investment in renewable energy is already taking a hit.
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investment → say → hit
This week, we’re asking how past fights over the oilsands got tangled up with separatism, what the referendum means for Alberta’s energy industry now and what an independent Alberta would mean for the climate.
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Alberta → ask → climate
What On Earth? drops new podcast episodes every Wednesday and Saturday.
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What → drop → episodes
…and 57 more, not listed.
The Aporia
