There are problems with the foundations of at least five of the 22 wind turbines installed this past summer at Nova Scotia Power’s wind farm on Nuttby Mountain, north of Truro, CBC News has learned.
Three of the turbines are shut down for repairs because the 400-tonne concrete pads were improperly installed, Mark Savory, vice-president of technical and construction services for Nova Scotia Power, said Wednesday.
The concrete was improperly installed at five of the towers, and don’t meet manufacturer’s tolerance levels for tower movement. Four more may also need repairing, he said. Two have already been fixed and are back in operation.
“We saw some cracking and that started us to say, ‘What’s going on?’ ” Savory said. “Then we started to notice what we thought was movement between the steel and the concrete.”
During construction last July at the $120-million wind farm, concrete was not vibrated down to the steel base of the tower.
“There’s a little bit of a gap and it’s like millimeters between the steel and the concrete. So what tends to happen is that can allow the turbine to move a little more than it’s supposed to,” Savory said.
Ratepayers are not on the hook, Savory said, because the towers are under warranty. The German supplier, Enercon Canada Inc., is paying for the repairs, which involves pumping in an epoxy like substance into the base.
“What you’re actually seeing is some surfacing cracking. If you think about it, it’s like a top hat and it it actually starts to rock a little bit, the concrete on the edge will crack and chip off,” Savory said.
Savory said this is a minor problem and should be fixed by the end of January.
Enercon, one of the biggest wind turbine suppliers in the world, did not respond to a request for a comment.
The Nova Scotia government has ordered NSPI to generate five per cent of its electricity from renewable sources next year, rising to 20 per cent in four years.