Electricity system operators 50Hertz (German) and Energinet (Danish) have inaugurated a hybrid offshore interconnector, the Combined Grid Solution (CGS), to integrate both German and Danish offshore wind farms. This is the first such project of its kind worldwide and is being implemented in the Baltic Sea, connecting two offshore wind substations to each other as well their existing onshore connections. Thus, the project can be used for cross-border energy trading as well as supplying offshore wind power to the countries of Denmark and Germany.

The CGS project is the first such electricity transmission connection between these two countries. The grid connections of 50Hertz-operated German wind farms Baltic 1 and Baltic 2, and those of the under-construction Danish wind farm Kriegers Flak are also used for interconnection. Both grid connection systems are linked through two 200 MW and 25 km long submarine cables. This is a joint project between the two nations with the participation of EU and costs a total of around 300 million Euros.

The CGS consists of both hardware and software components with the Master Controller for Interconnector Operation located in 50Hertz’ Control Center in Neuenhagen near Berlin. This digital control unit has multiple functions including synchronizing the requirements of power market with the actual energy generation based on wind resource at offshore project sites. CGS also enables grid stability for greater renewable energy integration into the electricity systems.