Cape Sharp Tidal turbine servicing steady at Port Saint John

OpenHydro tidal turbine under maintenance in Canada (Photo: Cape Sharp Tidal)

Cape Sharp Tidal has informed it is continuing with the maintenance and retrofitting operations on its tidal turbines at the Port Saint John in Canada with unspecified redeployment date.

The OpenHydro’s open-center tidal turbine, used by Cape Sharp Tidal for the Bay of Fundy tidal energy project, was recovered from the Minas Passage on June 15, 2017.

The turbine has since been undergoing a detailed inspection at Port Saint John that will also involve modifications to the components on its electrical sub-system attached to the subsea base and connected to the turbine, known as the turbine control center (TCC).

The second turbine for the project is also being serviced at the port, and the completion date of the maintenance operation as well as deployment/redeployment schedule for the turbines remains unknown.

Stacey Pineau, Cape Sharp Tidal’s spokesperson, said: “This is the first time this exact turbine design has been deployed in the world. Since the recovery of the Cape Sharp Tidal turbine, we have been taking the time needed to perform a detailed evaluation of the unit in port.

“The retrofitting of the second turbine is also ongoing in Saint John at this time. We’re not yet in a position to provide the timing of the redeployment of the recovered turbine or the deployment of the second turbine.”

The maintenance operations are related to a malfunctioning part identified in August 2016 which threatened the long-term performance and reliability of the turbines.

Cape Sharp Tidal, a joint venture between Emera and OpenHydro, is using the latter’s in-stream tidal technology whose design is based around four key components including a horizontal axis rotor, magnet generator, hydrodynamic duct and subsea gravity base foundation.

The turbine base sits on the seabed floor so no drilling is required for its installation, according to Cape Shape Tidal.

It’s called an in-stream turbine because it sits directly in the water flow that moves the fins, which in turn cause the rotor to turn. It’s completely different technology from the turbines used in dam tidal and hydro power sites, Cape Sharp Tidal noted.

The 2MW turbine is 16 meters in diameter, weighs 1,000 tonnes and stands 21 meters high.

The turbine rotor has 10 fins. Each fin is rounded along its entire edge, is 20 centimeters thick at the base, and 1.5 centimeters thick at the rounded tip.

The rotor turns an average of 6-8 times a minute, taking 10 second to complete one full rotation at that speed.

This is the strongest and heaviest turbine designed by OpenHydro so that it can withstand the powerful Bay of Fundy tides, according to Cape Sharp Tidal.

To remind, the turbine was installed at one of the testing berths of the Fundy Ocean Research Center (FORCE) in November 2016. It started delivering electricity to the grid later that year, producing enough energy to power 500 Nova Scotia homes.

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