By Louise Gray, Environment Correspondent, UK Telegraph

Britain’s wind farms have stopped working during the cold snap due to lack of wind, it has emerged, as scientists claimed half the world’s energy could soon be from renewables. The Met Office said there has been an unusually long period of high pressure across the UK for the last couple of weeks, causing the cold snap and very little wind.

Since Boxing Day much of the country has suffered sub-zero conditions with frozen rivers and lakes and even the sea in the south of England, at Sandbanks in Dorset. In the last few days temperatures in southern England plunged as low as 17.6F (-8C). However the weather is expected to warm up over the weekend, with wind speeds also picking up. But sources in the energy industry say that the lack of wind has caused the country’s wind farms to grind to a halt when more electricity than ever is needed for heating, forcing the grid to rely on back up from fossil fuels or other renewable energy sources.

In the long term, experts fear that the intermittent nature of wind will force the UK to rely on insecure energy supplies, for example gas from Russia, and are calling for a greater energy mix including controversial nuclear and coal-fired power stations. The continuing row between Russia and the Ukraine over gas supplies mean that Moscow cut supplies to the rest of Europe, sparking shortages that have hit 18 countries so far.

John Constable, research director at the Renewable Energy Foundation, said wind has been generating at a sixth of total capacity for much of the last couple of weeks, dropping to almost zero at times.  “This shows that wind provides very little firm, reliable capacity,” he said. “At times of high demand in cold weather there is a tendency for there to be no wind.” Power generator E.On said wind energy supplies have dipped 60 per cent in the last couple of weeks, when compared to the last fortnight in December.

A spokesman said: “As a country we need to keep the lights on, reduce our environmental impact, and do that in the most affordable way for our customers. Sadly there is no single miracle cure to do that. “Renewables, such as wind, have a big part to play now and in the future but in order to guarantee a secure electricity supply it’s clear we need a mix of power stations including cleaner coal, new nuclear and gas.”

Europe has pledged to source 20 per cent of energy from renewable sources by 2020. Dr Constable said the current crisis in European gas supplies highlighted the danger of relying on an energy supply that needs to be backed up with other sources and called for a mix of alternatives. “At the moment it is not a problem because we have supplies of oil and gas from the North Sea but when we go 11 years down the line when we have 20 per cent from renewables and we have a similar weather pattern then we have a problem.” However advocates of renewables said the intermittent nature of wind will not be a problem in the long run because supplies could be shared worldwide, enabling a constant source of energy. Read more here.

Icecap Note: Last winter when a “blue norther” brought cold into Texas, which relies increasingly on high plains wind power for electricity, electric heat and furnaces kicked on for heat. As high pressure settled in and winds went calm, lights and furnaces went quiet. Wind and solar are not reliable and must always have a ready back-up or needs to be accepted as only a part of solution that uses multiple sources including nuclear, hydro, natural gas/oil/clean coal generation.