Major problems in Foula’s award-winning renewable energy system have meant folk are back to using generators to supply their electricity.
Shetland’s most remote island last year became the first in Shetland to become totally self-sufficient in energy with a scheme that incorporated wind turbines, a hydro scheme and solar panels.
But the island’s three wind turbines have been out of action since December when a fault in the high voltage cable meant they had to be turned off as they were feeding through the cable.
Then on 25th December hurricane force winds buckled the blades of one of the turbines. Subsequently the heads and blades of all three were sent back to the manufacturers, Westwind of Northern Ireland, to be upgraded. They have still not been returned. The masts were then taken down and remain lying on the ground. It is not known when the turbines will be re-instated, as they are not allowed to work in Foula’s important bird breeding season (May to September).
Although the island suffered intermittent power failures since then, a new 400 metre section of cable between two transformers seemed to be the answer and islanders enjoyed electricity from the hydro scheme and solar panels.
However last Tuesday the renewable system failed completely after a series of power cuts since the second week of the month. For the last week and a half islanders have had to rely on manually-operated generators, with power only available from 7am to 12.30am. On Saturday the generator would not start and the island was without power for 17 hours until an engineer from Malakoff, which has the contract for maintenance and management of the scheme, arrived to get the generator going.
Local councillor Frank Robertson said the fault was in one of the main relays, the computerised switching gear which controls the system. But there is no indication when the renewable system will be functioning again.
Mr Robertson said: “There is a fairly complex control system managing the hydro, solar, wind turbines and the emergency generator. One of the main relays controlling the system failed. This resulted in the renewable system shutting off and the emergency generators having to be operated manually. These should come in automatically when any element of the system ceases to function, but in this instance failure of the relay was the problem.
“The Malakoff have identified the problem, relays have been ordered and we are currently awaiting their delivery.” The possibility of having spares to hand will be looked at, he said, but due to the expense it is not possible to have every spare part. It is understood that replacement relays were sent to the island but turned out to be the wrong ones.
Although Foula’s renewable system has been dogged by problems, Mr Robertson is optimistic: “This is just normal snagging that installers have to deal with until the whole system is tried and fully tested. Although it’s an inconvenience they [residents] are accepting the reduction in electricity.”
December’s fault in the high voltage cable led to all the isle losing power for some time. Fortunately engineers from Malakoff were able to isolate the fault that day and power to some properties was soon restored – others had to wait two days for the arrival of a 20kw emergency generator. This later broke down, meaning more power cuts for two and a half months until the faulty section of cable, which dated from an original 1980s installation, was replaced last month.
The £1.5 million renewable energy scheme, which had been years in the planning and in which its last part, the wind turbines, were switched on in October, won an environmental award in November.