Danish electricity system operator Energinet has announced that it is ready to design high-voltage substations so that Bornholm’s power grid can be effectively connected to new energy projects. We are talking about the construction of the landmark Bornholm Energy Island project and offshore wind farms.

Energinet is currently in dialogue with the Bornholm City Council on the objectives of the work to connect Bornholm’s electricity network to the electricity network of the future Energy Island.

According to preliminary analyses, it is probably technically feasible to connect the power island cables to the Bornholm electricity grid without affecting the stability or security of supply of the overall electricity grid on Bornholm or elsewhere.

Bornholm, Graphics: Energinet

Most importantly, connecting Bornholm’s electricity grid to Energy Island will result in socio-economic savings. Bornholm is currently connected to Zealand’s power grid via a submarine cable leading to Sweden. To maintain security of supply, Energinet pays for a power plant on Bornholm that is ready to produce electricity in the event of a break or fault in the power cable running to Sweden. This cost can be saved if Bornholm’s electricity grid is connected directly to the Energinet system.

Energinet will start developing technological solutions for the connection of the Bornolm Island system to the future Energy Island.

– Never before has it been possible to combine a large DC system with very high voltage levels with a small local AC network with relatively low voltage levels. We therefore need to start a dialogue with market participants and researchers as soon as possible on how best to solve this task,” explains Kim Søgaard Mikkelsen, Energinet Chief Project Manager for the Bornholm Energy Island.

Energinet is currently continuing technical analysis and development work to ensure that the selected solutions do not jeopardize the stability, security of supply, or schedule of the project. Preliminary assessments from the analysis indicate that it is likely that it will be possible to connect the Bornholm electricity grid to the Power Island electricity infrastructure via a 60 kV connection. Cost estimates for the various technical options are still subject to uncertainty, but it is currently estimated that the most expensive option will cost approximately DKK 230 million in additional construction costs.

Source: Energinet