Renewable energy generators are unhappy with being hit with a "windfall tax" by the UK Government.
They claim the move announced yesterday as part of a new Energy Prices Bill "risks skewing investment towards the fossil fuels that have caused this energy crisis".
But the UK Government says it could save billions of pounds for energy consumers.
The legislation includes a temporary "cost-plus-revenue limit" in England and Wales, which will reduce the profits the generators can make by severing the link between high global gas prices and the cost of their low-carbon electricity.
As things stand, this part of the bill will only apply south of the border, but the UK Government says it is liaising with the Scottish Government to confirm whether the measure will extend to Scotland.
If Holyrood refused to follow the lead of Westminster, then it would put the Scottish Government in a difficult situation as the cost-plus-revenue limit could see electricity users south of the border having to pay far less for their power than consumers in Scotland.
Full scope
The full scope of the limit is still being determined, but it will apply to low-carbon generating assets not currently covered by a contract for difference which agrees a price for energy with the government.
Older wind and solar energy projects will be affected, and there's also a risk to nuclear and biomass generation.
The precise mechanics of the limit are to be subject to a consultation to be launched shortly.
The UK Government said it has been working closely with industry on the detail of the proposal, ahead of it coming into force from the start of 2023, and added: "It will ensure consumers pay a fair price for low-carbon energy and has the potential to save billions of pounds for British billpayers, while allowing generators to cover their costs, plus receive an appropriate revenue."
But trade body RenewableUK is disappointed at the sector being targeted.
CEO Dan McGrail told Energy Voice: "We are concerned that a price cap will send the wrong signal to investors in renewable energy in the UK."
100% tax
The group said this would be a "100% windfall tax on renewables revenue above a certain level" which "risks skewing investment towards the fossil fuels that have caused this energy crisis".
Mr McGrail added: "It is essential that a cap is set at a level that doesn't make the UK less attractive to investors than the EU, is technology neutral and has a clear sunset clause in place.
"Most wind generators sell their power a year or more in advance at prices that are a fraction of the record high market prices being set by gas.
"These hedging arrangements for wind power will help to keep electricity prices lower for consumers this winter, and the price cap must not undermine these arrangements.
"Industry has been proactive in proposing new fixed-price contracts to cut costs and provide long-term, low-cost power for consumers.
"We welcome the inclusion of this proposal in the Bill, and it is vital that the scheme is developed rapidly so that industry can plan for new contracts and consumers can be confident that they are getting maximum benefit from cheap renewables."
Deeply worried
Keith Anderson, chief executive of ScottishPower, was deeply worried at the suggestion renewable generators are making "extraordinary profits".
He said: "It's disappointing that such a significant market intervention by the government has come with so little detail - all this does is create uncertainty.
Earlier this year, North Sea oil and gas producers were hit by a windfall tax by the UK Government after energy prices rocketed.
Other sectors which have benefited from the value of hydrocarbons soaring were also believed to be in the sights of Westminster politicians.
This was confirmed at the weekend when it emerged the UK Government was pressing ahead with plans to cap the revenues the renewable electricity generators are making from sky-high wholesale power prices following Russia's invasion of Ukraine.