The tender for Hesselø OFW has been put on hold until the results of the preliminary site investigations have been further analysed. This decision is due to the preliminary site investigations having revealed soft clay formations, especially the upper 20-30 m below the seabed, in large parts of the area selected for the OFW (see the map below). The results appear to indicate less favourable site conditions than initially specified in the fine screening report, which may cause technical challenges in relation to installation.

Currently, external consultants are conducting further laboratory analyses to fully assess the strength properties of the top soil in the area. These analyses are expected to be concluded in the fall of 2021 after which the DEA intends to initiate a new market dialogue to discuss the consequences of the results with the market players.

Following the results of market dialogue and analyses, all input will be considered and the further tender process will be decided.

The preliminary site investigations are conducted by the Danish TSO, Energinet. The map illustrates the estimated thickness of the soft clay based on preliminary data from 40 Cone Penetration Tests conducted within the 247km2 area. The coloured map thus represents one of many gridded surfaces that fits the gathered data and the actual clay thickness may therefore deviate from the map illustration.

Key Facts 

• With the Energy Agreement of 29 June 2018 and subsequent Climate Agreement on energy and industry etc. of 22 June 2020, it was decided to initiate a tender for Hesselø Offshore Wind Farm with a capacity of 800-1,200MW and grid connection by 2027.
• The Danish Energy Agency issued the permit for Energinet to initiate preliminary site investigations of the Hesselø area in October 2020. The permit includes the following scope:

Geophysical and geotechnical surveys of:
- the area to Hesselø Offshore Wind Farm
- corridors for export cables
- locations for platforms

Marine biological studies
- Bentic flora and fauna
- Marine mammals
- Fish and fishing