Two proposed gas power stations worth a combined £200M have been accepted for examination by the Planning Inspectorate.
Energy firm Watt Power submitted plans for the 300MW simple-cycle gas turbine power stations at Hirwaun in South Wales and Eye in Suffolk.
They are designed to respond quickly and efficiently to short-term variations in demand and intermittent supply from certain renewables.
Engineering consultants Parsons Brinckerhoff is working with Watt Power on taking the schemes through the planning process.
The Planning Inspectorate examination will take up to nine months, after which the stations will require approval from the energy secretary.
It is hoped the projects will start operating by early 2019.