KPMG is refusing to publish the full findings of a controversial study examining the cost of the government's green energy policies, which was originally used as a basis for a series of media reports attacking the cost of renewable energy.

The preliminary findings of the report, dubbed Thinking about the Affordable, were made public last November. They claimed Britain could meet its 2020 carbon reduction targets more cost effectively by building nuclear and gas-fired power stations instead of wind farms.

The report was seized on by critics of the government's green agenda and also formed the basis of a number of media reports, including a BBC Panorama special that attacked the cost of renewable energy subsidies.

The preliminary findings of the report suggested the UK could save £34 billion (US$53 billion) by ditching plans for a massive expansion in wind power capacity and instead focusing on nuclear and gas capacity.

It was the first of a series of studies that have been published during the last few months, claiming wind power is too unreliable and costly to provide an effective means of keeping the lights on while reducing carbon emissions.

Trade body RenewableUK slammed the KPMG study as inaccurate on the grounds it had failed to consider the full lifetime and operating costs of new conventional power plants. Green campaigners have also repeatedly called upon KPMG to publish the full version of the report and disclose its methodology.

But Sorrelle Cooper, a spokeswoman for KPMG, told BusinessGreen that the company had decided not to release the full report as researchers had deemed it was "ripe for misinterpretation."

"The assumptions and parameters used in the model – which examined the investment and lifetime costs of different energy generation sources – produced large swings in the financial outcomes," she explained.

"To avoid any misinterpretation we have decided not to publish any findings, although we are discussing our analysis with interested clients and stakeholders in the energy industry."

Cooper acknowledged that a leaked press release, obtained by the Sunday Times, BBC's Panorama and BusinessGreen, had opened the study up to accusations of bias, which had also been a factor in the team's decision not to publish.

"Unfortunately things do get boiled down into a headline and the findings are too complex for that," she said.

Cooper admitted there had been mishandling of the release of the report, maintaining that the draft press release had been leaked, although she refused to provide further details on how it had been made public.

However, Cooper stood by KPMG's methodology, adding that the research team had since come to an agreement with RenewableUK over how the figures were derived.

She also maintained that KPMG had close ties with the green energy industry, was not "anti-wind" and had last week been involved in a major wind farm deal.

But a spokesman from RenewableUK said that while it had met with KPMG since the preliminary findings were published, it stood by its original concerns over the report's methodology.

"We welcome the decision by KPMG not to release this report. The methodology they used did not properly compare with how power generation systems function in the real world," he said.

"KPMG needs to be made more aware of the benefits of wind energy. The cost is just £10 per household per year, according to the independent regulator Ofgem. Gas hit a three-year high of 75p per therm in Britain on Friday [3 February] as a result of the cold snap across Europe. We have to get off the fossil fuel hook to stop our energy bills escalating."

In addition, Tom Heap, the BBC journalist behind the Panorama programme, insisted KPMG's preliminary findings had not been leaked, and had been made available to him in an official manner.

Writing on Twitter, following the news KPMG would not be issuing the full report, he said: "KPMG [interview] in @BBCPanorama on energy cost filmed in their HQ with company pr in attendance. Not a leak, could hardly get more official."

KPMG's reluctance to release the report will be seized on by green and renewable energy campaigners who have in recent months been forced to defend renewable energy policies from a series of reports about the cost of green energy, which they regard as misleading and inaccurate.

Renewable energy industry insiders expressed disappointment that KPMG was unwilling to release the controversial research, despite the fact that the preliminary findings had already been used to shape the current debate on energy policies.