Foundations for the Future of Power Supply

As one of the bigger Danish investments in wind power, the new Hesselø Offshore Wind Farm will produce power for approximately one million Danish homes. The wind farm will be placed north of Zealand in Kattegat, in Hesselø Bay, about 30 km from the coast.

To connect its power to the Danish electrical grid, the offshore wind farm needs to be linked to the transformer station by Hovegaard west of Ballerup. To this end, Artelia helped Energinet prepare the pilot project for an expansion of the station.

The task is part of a framework agreement we won in 2020. Since then, Artelia has contributed to several transformer station projects. At Hovegaard, our tasks concerned preliminary examinations for Hesselø Offshore Wind Farm and an expansion of the station to prepare for future changes to the high-voltage system. Our other transformer projects also include stations that are already in operation or about to be.

The green transition
The many different projects are part of the collective upgrade of the Danish electrical grid necessary to meet future demands. The future energy demands are influenced by both new sustainable energy sources, the increasing number of electric cars, electric heat pumps
in private homes and the electrification of public transport.

The transition to renewable energy sources forces the electricity system to undergo radical changes. Traditionally, electrical power production has taken place at centralised power plants many of which are situated near the larger Danish cities. Thus, power was produced
near to where it was mostly consumed and then transported to less populated areas. As the use of wind and solar power increases, the system is turned upside down. The power is now produced on the ocean or in the countryside and transported to less populated areas first. This forces large amounts of power to be transported across larger distances necessitating a substantial upgrade of the electrical grid, an upgrade also required by our society’s increasing use of power.

Stand-in for Viking Link
As wind energy produces more and more of the energy needed in Denmark, the turbines will at times produce more energy than we can consume. The opposite issue might also occur as both wind and solar power depend on weather conditions. Both issues require an exchange of power with our neighbouring countries, and the future Viking Link will therefore allow for an electrical connection between Denmark and England across the North Sea.

Such a valuable unit requires a trustworthy backup solution, and the electrical grid from Endrup to the border will ensure access to emergency power from central Europe. The project entails a considerable modernisation of the transformer station by Endrup located approximately 20 km from Esbjerg that is part of the list of Artelia projects and of about the same size as the project by Hovegaard.

A familiar discipline
Our role on the many transformer stations includes design, construction management and inspections of drainage and concrete foundations. These are some of our main areas of expertise at Artelia, as we have designed constructions for the energy sector since we were founded in 1930 and, previously, solved several tasks for Energinet.

One aspect of the project is to design robust structures, another is working under the special conditions the sector poses including maintaining the supply security. Usually, if we have two transformer stations, both in operation, we will tear one of them down and build a new one while keeping the other in operation until the first project is complete. Thus, we can keep up the supply.

Health and safety coordination is particularly important when working on facilities that contain such high levels of voltage. For the same reason, drainage is particularly important as power and water is a dangerous combination. Altogether, the projects require considerable logistical planning and because of the projects’ importance, security measures also need to prevent uninvited guests from entering the premises.