National Grid is on standby to alert households to cut their electricity usage in the coming days amid a looming supply squeeze.
The country's grid operator has warned that electricity supplies will be tight on Friday and Sunday amid low wind levels and a cold snap sweeping the UK.
It indicated it may need to use “enhanced actions” to shore-up supplies. These include a new scheme under which households can sign up to be paid to use less electricity to avert blackouts, for example by switching off the washing machine. Running extra-coal fired plants is another option.
A number of schools in Scotland were forced to shut on Thursday because of the severe cold weather with 5cm of snow falling in Aboyne, Aberdeenshire, and at Althnaharra in the Highlands.
Met Office chief meteorologist Steve Willington warned there is an “increasing risk of snow as the week progresses”.
In Sheffield, the Red Cross has been drafted in and a “major incident” declared, after a burst water main left thousands without gas.
Four people were killed across the UK in road traffic collisions as motorists tackled dangerous icy roads.
Concerns have been mounting over energy supplies this winter following cuts in Russian gas exports, affecting supplies of fuel for both heating and electricity generation.
In the coming days electricity supplies are set to be affected by fluctuating levels of wind, however, while nuclear capacity has also fallen due to major closures this year.
It will leave Britain more reliant on imports from the continent, despite concerns about the availability of French supplies this winter amid outages on its nuclear fleet. Britain was exporting power to France on Thursday afternoon as cold weather in the Continent also fuelled an increase in demand.
A host of weather warnings are in force across much of the UK, some until Sunday, with the Met Office warning that the ice, snow and sub-zero conditions brought by a blast of Arctic ice will last for at least a week.
Meanwhile charities warned that vulnerable elderly people were “incredibly worried” about the threat of blackouts during the cold spell.
Morgan Vine, head of policy at Independent Age, said: “The prospect of blackouts affecting older people’s heating and electricity supply this winter is incredibly worrying.
“Not being able to put the lights on or keep warm enough could put many older people’s health at risk, increasing the chance of falls and making some health conditions worse. Many older people also rely on equipment that needs continuous power, have telephones connected to their broadband routers or use their TV or radio to stay connected.”
Paul Buckworth of power market specialists EnAppSys, said higher levels of demand because of the cold weather and less windy conditions were the main factors driving National Grid's expected power squeeze.
He said: “National Grid Electricity System Operator's forecasts assume 4 gigawatts of imports into Great Britain from interconnected markets. This level of imports is stated to be as per their Winter Outlook base case scenario, but they note that actual flows will be driven by market price.”
According to National Grid forecasts published on Wednesday, wind generation in Britain is set to fall to 2.9 gigawatts on Friday and 1.1 gigawatts on Sunday, compared to 11 gigawatts on Tuesday.
That would leave the buffer of spare capacity falling below the levels National Grid deems adequate.
Wind generation is also expected to be relatively low on Saturday, although demand in the evening is likely to be lower as millions drop other activities to watch England’s World Cup quarter final clash against France.
National Grid said: “Margins are expected to be tighter this week, particularly for the next few days. This is based on our current assessment and is subject to change.
“Our control room has a range of operational tools available to manage this. These actions also include our enhanced actions.”
Electricity supply and demand has to be constantly matched to avert blackouts. The outlook for any given period becomes clearer nearer the time as traders start to lock in their positions and weather forecasts sharpen.
National Grid’s outlook communication is designed as a snapshot during a weekly operational forum, with the outlook changing as the week evolves.
On Thursday it declined to comment further on its expectations. It has to give 24 hours formal notice of any requirement for consumers to cut their usage, and had not given any as of Thursday evening.
Thomas Edwards of market specialists Cornwall Insight, said that, since National Grid’s warning on Wednesday, the day-ahead auction for power delivered on Friday had cleared at £511 per megawatt hour, indicating pressures had eased.