Political and regulatory differences between countries are slowing progress towards an offshore electricity grid in the North and Baltic seas, according to a report by an EU-funded group of eight organisations.
Market mechanisms for supporting offshore wind vary widely, as do the levels of support. There are also large differences in rules for connecting renewables to the system and in how electricity is traded.
Legal uncertainties raise questions such as who should pay for electricity produced in one country but sold abroad, or who should support an offshore plant built in one country's waters but connected elsewhere. These, together with the high cost of construction and the risk of stranded investments, will make financing another barrier, the report says.
The report, by the Offshore Grid consortium, finds that wind farm developers, operators and traders see harmonisation of electricity-market and grid-connection rules as essential for creating an offshore grid. In contrast, national policy makers would rather keep their support mechanisms intact and see a system of international co-ordination that would be compatible with national rules.
At the moment, inflexible regulators and purely national thinking are resulting in just single connections to individual wind farms. Nonetheless, most industry insiders believe that an offshore grid could be in place within 10 to 15 years, says the report. Many believe this will start with point-to-point interconnections between countries - with some already in place and several more planned. Interlinked - or "meshed" - grids will be developed later.
Meanwhile, ten companies have joined forces to lobby for a pan-European offshore grid network. The Friends of the Supergrid (FOSG) count among its members firms that will supply the high-voltage-direct-current (HVDC) infrastructure, developers, grid network operators and installation companies.
FOSG stresses that the supergrid will not be a mere extension of existing or planned point-to-point interconnectors, but is a trading tool which will involve "supernodes" out at sea to collect power from offshore renewable generators and route it to the best available markets.
At its launch in London, Eddie O'Connor, chief executive of developer Mainstream Renewable Power, said FOSG is uniquely placed to influence policy makers towards creating the supergrid.