Energy companies have warned that changes to the way onshore wind farms are subsidised could halt a multi-billion pound investment.
They are expected to invest about £50bn over the next 15 years in onshore wind farms to meet climate change targets.
But it is understood that a review of the renewable obligation certificate system - the method the Government uses to subsidise renewable energy projects - could result in less for onshore wind farms. A decision is expected in July.
Energy companies say that a cut in subsidies for onshore wind farms would force them to reassess their investment plans.
German energy giant RWE npower, one of Britain's top six energy suppliers, plans to invest about £1bn in onshore and offshore wind energy projects over the next year. Some of these projects could now be at risk.
Julia Lynch-Williams, managing director of RWE npower renewables, said: 'The review creates uncertainty and threatens the financing of new projects.
The indication is that onshore subsidies are going to reduce. If this happens, it will put onshore projects at risk and potentially destabilise investment in all renewables in the UK.'
One executive at a leading energy company said: 'Essentially, we require a long-term, stable regulatory framework to provide the confidence and certainty of returns to secure investment.'
Energy companies say that the uncertainty is not helpful for developers and may lead to a pause in renewables development and may also affect the Government's ability to hit targets.