An MSP is calling for a major inquiry into the cause of the power cut that left more than 200,000 properties in the dark across the north.
Highlands and Islands MSP David Stewart said the massive blackout was “very worrying” and he demanded answers from Scottish Hydro Electric Power Distribution about why one incident could black out such a wide area.
The inquiry call came as former top power boss Sir Donald Miller claimed the north transmission network was more vulnerable because of the way wind power was managed.
Mr Stewart said: “This in my experience is totally unprecedented, to have more than 200,000 customers affected by a loss of power. There still doesn’t appearto be an explanation.
“Whatever the reason, it is very worrying that this has happened. I will be calling for a major inquiry into how this has happened and will be raising the issue with Alex Salmond when I return to the Scottish Parliament next week. I want answers from the network operators.
“I’m very concerned about the potential accidents that could have happened during the time the power was out. My major concerns are the effects on businesses and the effect on vulnerable residents left in their homes without heat or light.”
The widespread power cut hit the Highlands, islands and Moray shortly after 8 .30 pm on Wednesday, affecting about 205,000 homes at its peak, with some premises out for three hours.
Yesterday, the former chairman of Scottish Power, Sir Donald Miller, said he believed the transmission network in the north was now “more vulnerable” due to the way wind power was being installed before the necessary transmission capacity was available.
Sir Donald, who was also chief engineer for the North of Scotland Hydro Electric Board in the 1960s, said that prior to the introduction of the “connect-and-manage” system for wind turbines in 2010, the transmission network could cope with its two greatest-capacity circuits in any area going down at any one time by switching off the faulty circuits.
This is done within a fraction of a second, so all that customers would notice is a momentary blink in the lights.
With the “connect-and-manage regime”, the network loading also has to be adjusted – for example, by shutting down some wind turbines – and this cannot be done in the same time frame.
Sir Donald believes this makes the system less robust and more prone to overloading. And he feels the risk to the system and reliability of the supply will increase the more wind turbines are installed.
A Hydro Electric Power Distribution spokeswoman apologised for the “rare and unexpected” blackout but, when asked if a wind power surge had been ruled out, said no more information could be given.
National Grid said there was “very accurate wind forecasting” and claimed wind power did not overload the grid.