EU state aid guidelines for renewable energy could hamper emerging technologies, slow the cost-decline of solar PV and put support for smaller scale projects at risk, according to 28 industry bodies.

In an open letter to Joaquin Almunia, vice-president of the European Commission and commissioner responsible for competition, the groups said proposed state aid changes, published in December, threatened the industry’s development.

“We, as 28 industry associations representative of the photovoltaic (PV) sector of the whole European Union, are however deeply concerned that the Environmental and Energy State Aid Guidelines (EEAG) proposals recently put forward by the European Commission will not only miss such an opportunity, but hamper the cost-effective and successful development of solar PV electricity and other renewable technologies in Europe,” the letter said.

Specifically, they are concerned that distinguishing between “deployed” and “less-deployed” technologies could create an uneven investment landscape in Europe.

By requiring technology neutral auctions, the most established technologies will be at an advantage and it will become harder for solar to continue cost reductions, the letter argues.

There are also fears that the auction process would not work for smaller projects.

“We also want to highlight the specificities of small-scale generation, for which market-based mechanisms such as auctioning procedures cannot be envisaged. Aid in the form of feed-in tariffs should therefore remain eligible for small installations and cooperatives-driven projects for all technologies below a 5MW threshold,” the groups warn.

Signatories to the letter included the UK's Solar Trade Association, Germany’s BSW, Spain’s UNEF and Italy’s GIFI.

The letter builds on previous concerns voiced by the European Photovoltaic Industry Association.