Fears are growing that the coalition could scrap existing plans to facilitate the development of solar power.
Campaigners believe a rushed review of a £400 million pot used to subsidise solar energy will make it impossible for housing associations, schools, hospitals and other mid-sized organisations to go ahead with solar installations.
The present system of feed-in tariffs was established in New Labour's final term to encourage small-scale renewable energy solutions. Enthusiasm for more solar development, especially through 'solar farms', is thought to have alarmed ministers.
The £400 million subsidy money is funded through a levy from energy companies. This has not stopped the Treasury viewing the funds as public money, however.
Economics campaigner Donna Hume of Friends of the Earth said ministerial reluctance to allow solar power to develop was part of their determination to "continually stamp on success".
"This is driven by the need to stay within this cap, because they've realised how much of it is in the pipeline," she told politics.co.uk.
"They're in danger of destroying investor confidence in the scheme."
Feed-in tariffs provide a subsidy for renewable energy under 5MW. All schemes providing above 50KW, including community schemes and housing associations doing fuel poverty projects, were included in the terms of reference of the fast-track review commenced last month.
Industry insiders had expected the review's findings to be released today, but publication appears to have been delayed until either tomorrow or early next week.
The Conservatives and Liberal Democrats had favoured expanding the scheme before the general election, arguing it could provide more than two per cent of Britain's energy mix.
Campaigners say six per cent is an achievable figure but fear ministers are now unlikely to follow through with ambitious plans.
Even environmentalists acknowledge the subsidy could be reduced because the costs of providing solar power have fallen.
FoE has argued for the feed-in tariffs review to be restricted above 500KW, not 50KW, and argues solar power will pay for itself by the end of the decade.