The owners of more than 600 small wind turbines have been told to shut them down amid fears of catastrophic mechanical failure.
Experts said lastnight that, in the worst-case scenario, blades could fly off theProven 35-2 generators, which are dotted all over the north of Scotland.
The troubled manufacturer of the turbines has suspended all sales and warned its biggest investor – the London-based Low Carbon Accelerator (LCA) fund – that it will not be able to cope with its current losses unless it gets another cash injection.
Proven Energy revealed drive shafts in the 35-2 model had an “acute” defect and told owners that the machines – which can produce up to 12.1 kilowatts and cost up to £70,000 – should be left stationary, with the “parking brake” applied. The advice to stop the turbines follows so far unspecified problems with three machines.
Engineers said a shaft problem potentially could cause built-in braking systems to fail and the turbine blades to fly off if they were turning faster than they were designed to cope with. About 500 of the generators have been put up in Scotland on 50ft towers. Many of them are owned by farmers.
Three north-east farmers were “surprised” when the P&J told them about problem yesterday.
Fred Hendry, of Byth Stone, and John McGrimmond, of Ladysheets, both Alvah, Banff, have turbines but they knew nothing about the plea to turn on the brakes.
Another farmer, who did not want to be named, has just had three turbines installed on his land.
Mr Hendry said his machine started generating on June 1 last year. “It was a lot of money for me, roughly about £50,000,” he said. “I’ve a lot of questions about what happens now as it is supposed to be under guarantee. I’m absolutely surprised.”
Mr McGrimmond’s turbine went into operation in March. He said: “This is the first I’ve heard of this. It has been working OK up to now. I went for it to get the feed-in tariff (subsidy) as it seemed a good thing at the time.”
The farmer, who has three generators, said none of his machines was operating as he had not finished installing them.
He said: “They’re braked at the moment and it looks as if the brake is going to kept on. They only went up in August. I presume, and hope, it will now be up to Proven to rectify this problem as soon as possible.”
LCA told the London Stock Exchange it expected to make either a substantial or total writedown of the £11.15 million it had invested so far in Proven, which has offices in East Kilbride and Ayrshire. LCA, which owns 81% of Proven, put £500,000 into the business only four weeks ago.
Proven described the shaft problem as a “potential defect” but LCA told the stock exchange it was “recent and acute”.
The defect does affect the Proven 7 Proven 11 turbines.
Proven could not be contacted for comment yesterday. Only the home page on its website was working and a message said it was investigating the problem. Work had shown that a “significant number of shafts” may be affected across multiple manufacturing batches.
Farmers’ union NFU Scotland said it had been unable to contact Proven but urged members to heed the advice to turn the brakes on. An NFU spokesman said it had noted the financial issues disclosed by Proven’s biggest investor.
He added: “This is clearly an evolving situation that will worry many of those who have installed or have been planning to install Proven Energy turbines.
“We have spoken to one major supplier of Proven equipment and he hopes to be in a position to write to all his customers next week clarifying the situation.”
The Scottish Government said it was aware of a manufacturing defect in the turbines, adding that anyone with concerns should check Proven’s website.