Emergency measures to prevent blackouts this winter as power crunch worsens

Emergency measures to fire up mothballed power stations could be used to keep the lights on this winter, after a series of power plant fires and closures left Britain more vulnerable to blackouts.

National Grid announced on Tuesday that it would begin recruiting idle or mothballed power plants, which would be paid to ensure they could fire up if needed as a "last resort".

The Grid had said in June that the emergency plan to boost power supplies would not be needed this year. However, it has resorted to using it because five of the power plants it had expected to be running this winter are now shut down or are in doubt.

In June, energy regulator Ofgem estimated there would be between 2.7 gigawatts (GW) and 5.4GW of spare operational power plants on the system – a capacity margin of between 5pc-10pc over and above peak winter demand.

But the situation has deteriorated as 3.67GW of power plants are now in doubt or shut down as a result of a series of incidents – threatening to wipe out the spare margin unless Grid recruits extra plants.

Two nuclear power plants have been temporarily shut down amid safety fears, two coal-fired power plant units have been partially shut after fires, and one gas-fired power plant unit is being shut because it is unprofitable.

"There is an increased level of uncertainty over the volume of plant that may be available in the market this winter," Grid said in a statement.

The plan to fire up mothballed power plants comes in addition to another emergency measure the Grid had already decided was needed this winter, to reduce demand by paying businesses to agree to switch off between 4pm and 8pm on weekdays.

Both demand and supply emergency measures were already due to be used in winter 2015-16 when Britain's spare capacity margin was already expected to fall to as low as 2pc.

The measures will be funded by consumers and are estimated to add £1 a year to household energy bills.

Peter Atherton, energy analyst at Liberum Capital, warned it was "a bit late in the day" for National Grid to be invoking the latest measure as it was "unlikely" that any plants that had been fully mothballed could now come back on in time for this winter.

However, plants that were shut and idle but not fully mothballed could come back more quickly, he said.

National Grid said it knew there were plants that "could make this winter’s deadline". "We would not be running the tender unless we thought we would get a response from industry," a spokesman said.

The biggest threat to this winter's supplies comes from doubts over two nuclear power plants, Heysham 1 and Hartlepool, with a combined capacity of 2.4 gigawatts (GW).

The plants were shut down in early August in order for owner EDF to carry out safety checks on key boiler equipment in the reactors following the discovery of "unexpected cracking" in one unit.

EDF said at the time it could not give an exact date for their return to service until investigations were completed, estimated to take "around eight weeks". Its website says they are due to resume operation in October.

But Grid said the outcome of EDF's investigations "may have an impact" on plant availability this winter.

"It is obviously a sign that National Grid are concerned that the two nukes may not come back on before winter kicks in," Mr Atherton said.

The spare capacity margin had already been dented when the Ferrybridge coal-fired power plant in Yorkshire suffered a fire in July. The fire-damaged unit, of 500 megawatt (MW) capacity is not expected to return to service this winter.

Another coal-fired power plant, Ironbridge in Shropshire, had announced in late May that a fire-damaged unit of 370MW would not be repaired.

And the owners of one gas-fired power plant, Barking in east London, announced plans to close it over two years because it was not profitable. Some 400MW could be lost this winter as a result.

However, a spokesman for the Grid confirmed that Barking would now be eligible to sign up for its emergency supplies scheme and could now be paid to remain operational this winter.

National Grid said that while it was putting both emergency measures in place, they would only actually be called upon as a "last resort".

Power plants that sign up to the scheme will effectively be paid a retainer to guarantee their availability, and then further payments if they are called upon to actually fire up.

Businesses who sign up for the weeknight closures to ease demand will also be paid a retainer even if they are never ultimately called upon to power down.

A spokesman for energy regulator Ofgem said: "We are confident that National Grid has the right levers to keep the lights on.

"However, no electricity system anywhere in the world can give a 100pc guarantee that the lights will stay on.

"Therefore given the tighter margins there can never be any room for complacency and National Grid and the industry must remain vigilant at all times.”

Ed Davey, the energy secretary, told the Telegraph in June: “The lights are going to stay on."