Saturday, June 12, 2010

Blades break off underwater turbine prototype

NSP, Irish partner forced to pull up 400-tonne unit a year early


Nova Scotia Power has suffered another setback in its $8.5-million experiment to try and generate electricity from the powerful Bay of Fundy tides.

Two large blades have broken off an underwater turbine, forcing the power company and its Irish partner, OpenHydro, to pull the 400-tonne prototype up from the bottom of the ocean floor a year early, Mark Savoury, a Nova Scotia Power vice-president, said Friday.

"The images are indicating we have a loss of two blades," Peter Corcoran, OpenHydro’s chief financial officer, told reporters at a news conference Friday in Halifax. "The Bay of Fundy is one of the world’s best tidal sites and I guess the world’s best tidal sites don’t come easy."

The companies can’t explain how the reinforced plastic rotors were damaged and want to pull the turbine out of the water later this summer or early fall so engineers can closely examine it.

The damaged turbine was discovered recently when a video camera was lowered 15 metres into the murky waters of the Bay of Fundy to film the turbine.

The video was taken back to Dublin for analysis by OpenHydro engineers, who quickly found images of the missing rotors. The company would not release footage to the media.

"I think at this stage, trying to determine timing and determine cause is incredibly difficult to do. Only until we have extracted the turbine will our engineers be able to really get inside that system," said Corcoran.

This latest news comes after The Chronicle Herald first reported in March that the company had lost contact with sensors on the turbine only seven days after it was lowered to the ocean floor last November in the Minas Passage. An acoustic modem failed to trigger sensors attached to the turbine to collect critical data about potential electrical production.

The turbid waters and strong currents in the Bay of Fundy prevent the company from sending divers to the site to fix the problem and it is difficult to take video footage.

Savoury said he hopes the turbine, located about 10 kilometres west of Parrsboro, will be repaired and can be put back into the water for further testing.

"This will involve no additional costs for Nova Scotia Power customers," said Savoury.

OpenHydro, a renewable energy company, will pick up the tab for the removal, repair and redeployment of the turbine back into the water. But Corcoran said it’s too early to say how much the repairs will cost.

Despite the setbacks, Nova Scotia Power and OpenHydro are committed to trying to tap this huge energy resource.

"It has one of the strongest resources known in the world and that is exactly why OpenHydro and NSP (are) deploying turbines here, and any lessons that we learn along this journey will only make the turbines stronger, and (the) likelihood of commercial tidal (power) possible," said Corcoran.

The massive steel turbine sitting on the seafloor is not connected to the power grid.

There are two other groups hoping to launch their tidal prototypes in the Bay of Fundy next year: Minas Basin Pulp and Power Company Ltd. of Hantsport and Clean Current Power Systems Inc. of British Columbia.

http://thechronicleherald.ca/Front/1186929.html

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