A European legal ruling has cast doubt on the future of on-site energy generation after judges ruled that a German law allowing a monopoly for on-site power generation contradicted EU law.

The Citiworks case involves Leipzig airport, which has an onsite energy system which supplies the airport itself and the commercial operators at the airport.

Power supply company Citiworks wanted access to the electricity network for Leipzig Airport under EU electricity liberalisation directives.

In the recent ruling, judges at the European Court of Justice at Strasbourg found that an arrangement in Germany, which permits a supply monopoly when they are ‘located on a geographically connected operating zone’, contravenes Directive 2003/54.

The Directive ensures an open energy market and national laws are only exempt under certain, unrelated circumstances. Legal and energy experts expressed concern at the ruling, which threatens to hold back the growth of on-site energy supplies elsewhere in Europe, including the UK.