Minas Passage tidal power off to bumpy start, figures show

OpenHydro manager Jeremy Poste after turbine deployment in November

Latest figures obtained by Warktimes show that in its first seven weeks of operation, the 2MW Cape Sharp tidal turbine sold only 5.4 megawatt hours of electricity to Nova Scotia Power (NSP). That’s equivalent to 2.7 hours of production at full capacity.

The information is contained in a two-page letter sent by NSP to the Nova Scotia Utility and Review Board (NSUARB) on January 31, 2017.

It means that at the guaranteed rate of 53 cents per kilowatt hour (or $530 per MWh), the turbine earned Cape Sharp a grand total of $2,862 from November 8, 2016, when it was connected to the grid, to December 31st.

Nova Scotia Power is required to report its purchases from the FORCE tidal test site every calendar year and so, this letter covers only 2016.

Turbine pulled for repairs

Cape Sharp Tidal Inc. announced on April 5 that it is pulling the turbine from the Minas Passage for “minor repairs and upgrades” to its electrical components. That decision along with these latest figures suggests that much work needs to be done to improve the turbine’s performance.

In its letter to the NSUARB, Nova Scotia Power says that although production is not yet at capacity, the turbine is “operating as expected at this early stage.”

Nova Scotia Power’s parent company, Emera, is a joint partner in Cape Sharp Tidal Inc. The other partner is turbine manufacturer, OpenHydro.

To read the Nova Scotia Power letter click here.

Emera responds

In an e-mail late this afternoon, Beverley Ware, who is speaking for Emera and Cape Sharp Tidal, says the turbine is still in the commissioning phase and it’s important that this phase “involve a slow and progressive ramp up of the technology under multiple tidal cycles.”

She adds that the “turbine has produced electricity for over 1,500 hours and we’re gradually increasing production over time as we identify where we can make improvements and possible upgrades.”

To read the e-mail from Emera Inc. click here.

Cape Sharp’s communications with the media and the public have been consistently upbeat.

For example, two weeks after deploying the turbine, the company issued a report on its website claiming, “We’re using just a fraction of the estimated 7,000 MW potential of the Minas Passage, to power the equivalent of about 500 Nova Scotia homes with energy from our tides.”

However, judging by the figures from Nova Scotia Power, the turbine produced enough electricity in its first seven weeks to power the equivalent of one Nova Scotia home for half a year.

And, 1,500 hours of production would power the equivalent of about 277 homes at full capacity. (Tidal turbines operate at much less than full capacity because the tides ebb and flow, so the actual number of equivalent homes would also be much less.)

Meantime, it’s not known how long repairs will take once the turbine is moved to Saint John, N.B. and when it might be ready for re-deployment at the Cape Sharp test site in the Minas Passage.

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