Nova Scotia Power asks regulator to let it pull plug on tidal project

Emera Inc.-owned Nova Scotia Power Inc. has asked a provincial regulator to allow it to retire Canada's only commercial tidal generating station and recover the costs of its abandonment.

In a redacted Feb. 19 filing with the Nova Scotia Utility and Review Board (M10013), the company asks the regulator to allow it to retire the Annapolis Royal Tidal Generating Station, which has been offline for repairs since Jan. 2019. The 20-MW facility was idled by the failure of an exciter, and its operation was dealt a further blow when a federal government agency said that continued operation of the 37-year-old plant would require authorization under Canada's Fisheries Act. The utility is asking the provincial regulator to allow it to amortize the C$25.8 million cost of retirement of the plant over 10 years and recover those costs from ratepayers.

"Nova Scotia Power factored these two events into the ongoing review and confirmed that the failure of the exciter constituted a 'run-to-failure' event," the filing said. "As the cost to refurbish the exciter exceeds the cumulative sustaining capital cost value associated with continued operation of the Station over a three year period, Nova Scotia Power has determined that the station has run to failure and should be retired."

The retirement would come as a blow to Nova Scotia's plans to wean itself from the coal, natural gas and oil-fired generators that provide the bulk of its power. The Annapolis generator is located on a causeway on the Annapolis River. It allows water to flow upstream when tides from the Bay of Fundy are rising and uses water rushing downstream as the tide goes out to turn its turbines. Since the plant went into operation in 1984, a number of smaller projects have been tested in the open waters of the Bay of Fundy but none have reached commercial operation. Canada's federal government recently invested C$28.5 million in tidal power project funding as part of its plan to reach net-zero emissions by 2050.