The UK exported electricity to France during last month’s cold snap, a new report shows.

An analysis of power demand during the so called “Beast from the East”, when evening peak demand hit a three-year high, exposed the country’s reliance on its biggest electricity interconnector with Europe, according to the Electricity Insights at Imperial College London.

The unit, which is supported by generator Drax, conducted an analysis of electricity flows between 26 February and 3 March – the third coldest six-day period during this century so far.

It says electricity demand increased 10 per cent, as people used more electric heating to keep warm. The evening peak demand on 1 March was the highest in three years.

Wholesale power prices surged five times the average for the quarter, peaking at £990 per MWh for one half hour amidst market volatility, which also saw them dip as low as £150 per MWh.

Despite surging demand for electricity pushing up prices, Great Britain’s interconnector exported power to Europe on two of the six coldest days.

This was because prices on the continent rose even higher than the UK to meet increasing demand from French consumers, who tend to use more electric heating than their UK counterparts.

Overall coal generation surged during the weeks surrounding the cold spell because rising gas prices meant it was more economical to burn than gas.

Total generation from fossil fuels remained around 20–25GW and wind output ranged from 11.8 to 13.8GW when demand for electricity peaked on 1 March. Up to 19GW of spare gas capacity was available if needed.

Dr Iain Staffell of Imperial College London, who co-authored the report, said “March 1 was the coldest spring day on record, averaging -3.8 C. These plunging temperatures put stress on the system due to surging demand. While thermal and renewable generation worked together to meet demand, Britain’s electricity link to France was less than helpful, which, ultimately, drove up wholesale power prices.

Andy Koss, chief executive of CEO Drax Power, added: “While the European interconnector is an important part of Great Britain’s electricity infrastructure, it responds solely to price. Therefore, if Europe has a cold snap, the country is at the end of the line, leaving consumers vulnerable to security of supply and higher price.

“As the country looks to procure future electricity capacity, the ‘Beast from the East’ is a reminder that security of supply must be the priority so that Great Britain doesn’t catch a cold when Europe sneezes.”