In their consideration of the evidence submitted by the UK Government the European Commission stated that:
'(282) The UK submitted that;......
(284) The aid would not have a negative impact on other low-carbon sources, given that they are also supported by the UK, and there is no discrimination against renewable technologies. The aid would actually support investment in a broad range of energy initiatives...'
But now, Amber Rudd, the new Conservative Secretary of State for Energy and Climate Change has announced that she will ensure that legislation will be introduced next year to end 'subsidies' for onshore windfarms. See http://www.businessgreen.com/bg/news/2408908/government-to-ban-onshore-wind-subsidies-from-may-2016-says-amber-rudd
So, it seems clear that the Commission's judgement giving consent to Hinkley C was based on a claim by the UK Government which cannot (now) be reasonably said to apply when Hinkley C starts generating and therefore gets paid its state aid incentives (2023???). If onshore wind is no longer able to be given reasonable CfDs (contracts for difference) that allow it to be built then clearly the aid to Hinkley C would be discriminating against a very important renewable energy technology, namely onshore wind. Hence the logic upon which the Commission gave its consent no longer applies. This will add considerable weight to the efforts to appeal against the Commission decision.
Austria and Luxembourg are said to be launching appeals against the Commission's decision to grant state aid permission to Hinkley C nuclear power station.