The Commission has doubts “that the project suffers from a genuine market failure” and that contracts-for-difference do not conform to the state aid regulations.
Joaquín Almunia, commission vice president, said: “The UK has notified a mechanism which is explicitly aimed at attracting investment in nuclear energy.
“It is a complex measure of an unprecedented nature and scale.
“The Commission therefore needs to investigate thoroughly its impact on the UK and the EU internal energy markets, and is requesting all interested parties to submit their observations.”
In the inquiry, the Commission will assess whether the construction of a nuclear power station could not be achieved by market forces alone, without state intervention.
EDF, which will build and operate the proposed Hinkley Point C plant, said the investigation will allow it, the UK government, and other parties “to show that Electricity Market Reform (EMR) is essential in order to give the UK the secure, low carbon electricity it needs for the future”.
It added that the aims of EMR, and the contracts-for-difference regime, are “in line with European objectives”.
EDF said it will cooperate fully with both the European Commission and the UK government as the investigation proceeds.