Britain's investment in wind farms has been branded a "folly" in a report on their ability to reduce the UK's carbon emissions, which concludes that wind power is expensive and inefficient, particularly when compared to nuclear energy.

The report, authored by respected economist and former economic adviser to the government, Ruth Lea [PDF], comes from the independent think-tank Civitas, which claims to have no political allegiance.

"There is no economic case for wind power," the report concludes, saying that while onshore wind appears to be economically competitive, it fails to take account additional costs incurred in gathering the energy. Civitas says it has used analysis from work undertaken for the government by engineering consultants Mott MacDonald, which suggests that British weather patterns in winter often lead to a combination of cold weather with very little wind.

This, says Civitas, means that wind farms are often unable to compete with other forms of energy when demand is at its highest - when it's cold.

The report comes as Energy Secretary Chris Huhne is reportedly planning a new generation of wind farms for Britain.

Civitas also claims that because wind farms are often situated far from the people who will consume their energy, the costs of sending that electricity to where it's needed is much higher than other forms of energy.

These factors mean that while nuclear power costs £67 per Megawatt hour (MWh), onshore wind farms cost £146/MWh and offshore wind is even more expensive at nearly £180/MWh. The two forms of wind energy are the most expensive ways of generating electricity, claims the report.

It concludes: "Wind-power is unreliable and intermittent and requires conventional back-up plant to provide electricity when the wind is either blowing at very low speeds (or not at all) or with uncontrolled variability (intermittency)."

The report will be seized upon with relish by the numerous campaign groups who oppose wind-farms, who dislike them on aesthetic, economic and agricultural grounds.

While wind farms work well in parts of the UK including western Scotland, sometimes there is such a thing as too much wind. The fierce gales that swept Britain over Christmas were so strong some wind farms had to be shut down, according to The Telegraph. This allegedly cost the taxpayer millions.

On the 9th of December a wind turbine in North Ayrshire caught fire during one of the strong gales. The trade body representing renewable energy firms described it as a "freak occurrence" at the time.

A spokesperson for the Department of Energy and Climate Change acknowledged they were trying to reduce the costs associated with wind energy, but said there was still a powerful case for using it:

“Onshore wind is one of the most cost effective large scale renewable technologies, and being one of the windiest places in Europe it makes perfect sense to exploit this natural resource," she said.

"Wind farms provide home-grown renewable energy, reduce our reliance on fossil fuels, cut carbon emissions and bring huge investment to support jobs and growth.

"Value for money is vital so that is why we have set up a task force to help bring down the cost of offshore wind and why we are proposing to reduce support for onshore wind as costs come down.”