The German government states the renewables act does not constitute state aid, including the controversial relief provided to industry in the form of reduced rates on the renewables levy.
The European Commission had opened the investigation on 18 December 2013, today is the final deadline for appeals.
The German government stressed that despite the court appeal, its continued intention is to find a solution in dialogue with the European Commission.
In its official response to the formal investigation on 20 January 2014, the German government had said it intends to tackle the industry relief as part of the upcoming reform of the Renewable Energy Act this year.
The EC investigation is looking into the support mechanism as defined by the Renewable Energy Act of 2012.
The EC is concerned whether the various exemptions and reductions granted to energy-intensive consumers on a surcharge, designed to finance renewable energy projects, are compatible with EU rules.
While it is still early days, the investigation risks undermining the German wind industry by destabilising investors and threatening jobs, industry observers fear. It will also make discussions about the reform of the act, already under way in Germany, more complicated.