Substantial investment is required in electricity infrastructure in the northern seas area in order to cope with the growing need for offshore wind energy interconnection and, despite its higher cost, a meshed grid is best suited to meet this need, according to a study of the benefits of a meshed offshore grid published by the European Commission.
A northern seas offshore grid, interconnecting national electricity grids and connecting offshore wind farms to shore, was identified as one of six infrastructure priorities for the European Union in the EC’s Second Strategic Energy Review and in EU regulation No 347/2013 on guidelines for trans-European energy infrastructure. The European Commission subsequently launched a request for services entitled “Study on the benefits of a meshed offshore grid in Northern Seas region” to assess the full suite of potential benefits of a meshed offshore grid in the North Sea, the Irish Sea and the English Channel.
The study examined two possible approaches to the development of offshore electricity infrastructure. The first is a business-as-usual approach, under which all wind farms are connected individually to shore and there is a limited number of point-to-point interconnectors, all of which require coordination between no more than two countries. The second approach is more coordinated, wherein several neighbouring wind farms are clustered and jointly connected to shore and countries are better interconnected through interconnectors that link several countries.
The infrastructure investment cost of the meshed grid is EUR 4.9 to 10.3 billion higher than for the radial grid. Nevertheless, the study has conclusively shown that the coordinated approach has more benefits: the annual savings including costs of losses, CO2 emissions and generation savings are EUR 1.5 to 5.1 billion higher per year for the coordinated grid, which largely compensates for its higher cost. These monetized benefits make the meshed grid profitable in all studied scenarios and for a wide range of fuel and CO2 costs.
When states also coordinate their reserve capacity, an additional EUR 3.4 to 7.8 billion generation investment cost reduction is obtained. These monetized benefits make the coordinated offshore grid profitable in all scenarios and, on top of the monetized benefits, there are fewer CO2 emissions and fewer cables making landfall in the meshed configuration.