A large number of older coal-fired power stations which until recently had been operating on restricted hours as they incur tough emissions restrictions are working around the clock to counter concerns over dwindling energy stocks during the extreme cold weather.

Andrew Horstead, risk analyst for energy and carbon specialist Utilyx, said: "The extreme conditions of the last week show that now, more than ever, the UK government needs to embrace a diverse mix of energy. While it is important to commit to the low-carbon sources of energy, we need to ensure that energy can be quickly accessed in times of peak demand through improved gas storage and investment in clean-coal power stations."

There are also suggestions that power plants are using the panic over energy supply to burn dirtier "brown" coal.

As demand from freezing households goes off the scale, coal has leapfrogged gas to become Britain's number one energy source. It now accounts for 45% of the UK energy mix compared with natural gas at 37%, according to the latest figures from Elexon, the company responsible for balancing the market.

Associated British Ports says its port at Immingham has seen a significant increase in coal imports. "[This] is expected to carry on at a higher than normal rate during the cold snap," the company confirmed.

Power generating firm Drax bought huge amounts of coal when prices fell last year. "Drax is burning a lot. It is a swing producer and can ratchet up quickly if called upon," said a spokesman.

Nick Rau, energy campaigner at Friends of the Earth, said: "This surge in the burning of coal is a knee-jerk reaction, but it reveals that we haven't approached energy provision in a strategic way."

Nick Mathiason
The Observer, Sunday 10 January 2010