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Lack Of Wind Or Delayed Nuclear Return ‘Could Wipe Out UK’s Spare Power Capacity’

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Emily Gosden, The Daily Telegraph

A cold and windless day could result in households’ lights being dimmed this winter, despite new emergency measures to prevent blackouts, experts have warned.

Britain’s spare capacity – the safety buffer between electricity supplies and peak demand – has fallen to just 4 per cent, the lowest level in seven years, following a series of power plant fires and closures, analysis from National Grid revealed.

Ministers on Tuesday insisted there would be no blackouts, thanks to emergency measures to bolster the margin back up to 6 per cent – higher than last year – by paying three power plants millions of pounds to guarantee their availability and paying factories to switch off during times of peak demand.

But experts cast doubt on those assurances.

The enhanced 6 per cent safety buffer relies on the timely restart in November and December of two nuclear power plants that are currently closed for safety checks. Their owner, EDF, has already delayed their restart once.

It also assumes Britain’s wind farms will deliver 1.7GW of power, some 23 per cent of their maximum output, despite recent warnings that windless spells with much lower output can occur even in mid-winter.

The combined effect of the nuclear plant not restarting and a windless day would be to “wipe out” the spare capacity margin, Peter Atherton, energy analyst at investment bank Liberum Capital, said.

Electricity supplies could also come under pressure if low wind coincides with an exceptionally cold spell, such as the kind of weather seen in early 2010, which Grid says is a 1-in-20 year event.

In the event of power shortages National Grid could intervene to prevent blackouts by using further emergency measures such as reducing voltage, resulting in dimmed lights.

National Grid said that even in an unusually cold winter, it believed there would be fewer than three hours in which it might have to take such steps.

It said this assessment already included the potential for “very low wind” and “delayed nuclear return”, and that this eventuality would not completely wipe out the spare margin.

The company said there would be other measures, such as ramping up electricity imports from the continent and asking power stations to run at full tilt, which could be used before it would dim lights.

It added: “No-wind days are now very rare given the amount of wind generation in the country and where it is based.”

Mr Atherton said that irrespective of the eventual margin, the fact National Grid had had to “cobble together” the emergency measures to guarantee extra power plants “demonstrates a shocking failure in UK energy policy”.

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