Nova Scotia Energy offered extra proof this week to justify its determination to completely retire the Annapolis tidal energy producing station, claiming federal fish passage necessities would shut down the power for a number of months annually.
NSP has utilized to the Nova Scotia Utility and Evaluate Board to put in writing off the 37-year-old producing station and cost ratepayers $27 million over the following decade to get better the remaining worth of the asset.
The station, which produced sufficient electrical energy to energy 4,500 houses, stopped operations in 2019 after a generator failure and an order issued that very same 12 months from the Division of Fisheries and Oceans.
DFO dominated the turbine blades had been killing fish within the Annapolis River and the plant would require authorization beneath the Fisheries Act to function sooner or later.
“The geography and configuration of the Annapolis Tidal Plant space make it difficult to develop and keep efficient fish steering programs to discourage fish from getting into the turbine,” NSP instructed the utility and overview board this week.
“Subsequently, primarily based on NS Energy’s expertise, beneath a DFO authorization, the potential operational modifications had been understood to be an entire shutdown interval (i.e. full month) to permit for fish migration of crucial species.”
4 months of shutdowns
The corporate modelled the period of time the plant can be shut all the way down to accommodate fish passage, however the info was filed confidentially.
In response to questions from the regulator, it did present a desk displaying fish migration durations that had been used as the premise for its estimates.
The chart confirmed gaspereau and shad migration happens over 4 months from April to July. Migration of American eel was listed from August to December, and tomcod in January and February.
NSP launched a variety of shutdown likelihood, and located 4 months annually was most definitely.
DFO mentioned it solely indicated that authorization was required.
“As a part of a Fisheries Act authorization utility, it’s the accountability of the proponent to develop and current methods the venture might keep away from, mitigate or offset impacts to fish and fish habitat,” DFO instructed CBC Information.
It additionally mentioned Nova Scotia Energy has not utilized for Fisheries Act authorization for the power.
The ability firm wouldn’t remark.
Retiring station ‘extraordinarily important’
NSP will now submit a separate utility for approval to decommission North America’s first tidal producing station.
“I believe it is extraordinarily important. That is one thing that is had a reasonably profound influence on the Annapolis River, on fish populations, on the land upstream of the tidal producing station,” mentioned Levi Cliche, govt director of the Clear Annapolis River Venture, a conservation group within the space.
Nova Scotia Energy is completely retiring its Annapolis Royal, N.S., producing station, which has been shut down since 2019. (Patrick Callaghan/CBC)
“We have now quite a bit to consider by way of how we transfer ahead. We actually want to think about how this infrastructure operates and the way it’s altered for the good thing about the ecology and landowners going ahead.”
The seven-metre, 148-tonne turbine is positioned in a causeway throughout the Annapolis River constructed within the Nineteen Sixties to guard farmland upriver from being flooded by the Bay of Fundy tides.
Environmental evaluation wanted
The causeway diminished tidal motion upstream, resulting in low oxygen situations and nutrient buildup, mentioned Cliche.
The tidal energy producing station offered elevated flushing, higher mixing and a few localized ecological enhancements.
Cliche mentioned eradicating the causeway would totally restore tidal flows however improve erosion and threat overtopping dikes that haven’t been maintained in many years, threatening current farmland and personal properties.
“It is difficult,” he mentioned.
For fish within the Annapolis River system, removing of the spinning blades is an efficient factor.
“The tidal producing station has brought about mortality of a number of completely different species over various years and has impacted inhabitants, although the extent of which is not actually totally understood. However it will possibly solely be a profit to species restoration,” mentioned Cliche.
Decommissioning the station would require an environmental evaluation. In earlier filings, NSP has estimated the associated fee at over $200 million.
The utility is obligated to return the causeway to the province within the state it discovered it.
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