Lack of wind or nuclear problems 'could wipe out UK's spare power capacity'

Household lights could be dimmed this winter if wind doesn't blow and nuclear plants stay offline - despite new emergency measures to prevent blackouts, experts warn

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”.

The emergency supply plans were designed to secure extra capacity from power plants “that would otherwise be closed or mothballed”.

But one of the three plants that will be paid through the scheme - ScottishPower’s Rye House gas plant – was expected to have been available in the market anyway, raising questions over why it has secured the extra cash.

Ofgem, the energy regulator, said that the introduction of the emergency measures was expected to cost less than £1 per household each year and meant the ultimate risk of blackouts was no worse than last year.
Matthew Hancock, the energy minister, pledged: “There will be no power cuts to householders.”

But the Institute of Directors said: “That we are even talking about the possibility of blackouts is in itself a massive policy failure”.

In its report on winter energy supplies, National Grid also warned that UK gas prices would soar if Vladimir Putin limits gas exports from Russia this winter.

Any disruption to Russian exports to Europe is likely to have the knock-on effect of forcing Britain to pay “significantly higher” prices to import more gas by ship from elsewhere in the world, it said.

A spokesman for EDF said it still expected to restart its nuclear plants as scheduled.