A row has erupted over the UK's ability to address the energy gap over the next decade following the publication today of a controversial report arguing that the government's focus on expanding wind capacity and failure to develop back up nuclear and fossil fuel capacity will lead to widespread power cuts.

The report from energy industry analysts Fells Associates argues that with a third of the UK's generation capacity due to be decommissioned by 2020 as nuclear and fossil fuel power stations are retired, prolonged power cuts could become a common occurrence from 2013.

Critics, including the business secretary John Hutton, immediately accused the report of exaggerating the scale of the threat, while hugely underestimating the ability of renewable energy to address the energy gap.

But speaking to reporters earlier today, report co-author professor Ian Fells, a long term supporter of nuclear power, said that the planned expansion of wind energy could not be delivered quickly enough to plug the gap, while the long-promised expansion in nuclear capacity was also not being built at sufficient pace.

The report, titled A Pragmatic Energy Policy for the UK, argued that the only way to plug the energy gap in the short term is to extend the life of fossil fuel and nuclear power plants, while accelerating the development of a new fleet of nuclear reactors to work alongside increased renewables capacity. It claimed that the need to secure energy supplies was now so urgent that it should take priority over climate change in the government's energy strategy.

Speaking to BusinessGreen.com, report co-author Candida Whitmill, said that while the long term goal had to be to reduce carbon emissions, that could only be achieved with a strong economy and as such, energy security had to be achieved first.

She also argued that the threat of power cuts provided a further incentive for firms to cut their energy use and invest in energy efficiency measures, although she warned that such efforts may help ease energy demand, but would not prove sufficient to solve the problem.

Government projections that an increase in offshore wind capacity to 33GW by 2020 will help plug the energy gap were branded technically impossible by Whitmill, who argued that there was just one installation barge available and that the UK wind industry would struggle to deliver more than 350MW of new offshore capacity a year.

"Wind is not going to happen and even if it did, we'd still need back up capacity [for when the wind is not blowing]," she said. "We have to go with nuclear power which offers the only sufficient base load of power that is low carbon… wind has a role to play, but not at the levels the government is talking about."

She also argued that the development of the Severn Tidal Barrage, an increase in biomass capacity and an extension of the energy grid to France, Germany and Scandinavia could also help deliver a lower carbon energy mix that provides a more secure supply than one based to a large extent on wind.

However, critics lined up to slam the report as inaccurate and biased, accusing it of exaggerating the scale of the potential energy gap and down playing the wind industry's ability to meet government targets.

"Ian Fells overstates the risk of the energy gap, but he also understates what the government's already doing to secure our future supplies and increase our energy independence," said business secretary John Hutton. "That's not to underestimate the task we've got on our hands. Securing future energy supplies for the UK is a matter of national security, so we're not going to rule out any radical options."

Meanwhile, Greenpeace chief scientist Doug Parr said the report meant that Fells had "finally lost the backing of the scientific community", adding that it showed a disregard for the extent to which other countries were fast embracing renewables to address their energy gaps.

"All over the world, jobs are being created in the renewable energy sector," he said. "But Britain has been left behind for too long by the negative, white flag approach to climate change that this report represents. Professor Fells has a long-standing love affair with the technologies of the 20th Century, but as time goes by his fetish for coal and nuclear power looks increasingly naive."

The starkest criticism was delivered by the British Wind Energy Association, which accused the report of "factual inaccuracies" regarding the wind industry's ability to deliver capacity.

Speaking to BusinessGreen.com, Dr Gordon Edge said that far from there being just one barge capable of installing offshore wind farms working in the UK, there were seven already in operation and more to be built over the next few years. He added that Whitmill's claim that the UK could only install 350MW of offshore capacity a year was also "just plain wrong", predicting the sector would be "doing more than that in 2009".

Edge also rejected the report's claim that a huge increase in conventional fossil fuel and nuclear capacity will be required to provide back up for renewables, arguing that rival models had shown that renewable energy could be relied on. "We will require some back up for peak loads, but you need less conventional plants with renewables than we have now," he said. "When you combine wind, hydro, biomass and other forms you can rely on a renewables mix."