Environmental assessments for Hesselø Offshore Wind Farm

Istock Vindmøller Offshore

Prior to the construction of offshore wind farms, an assessment of the effects on the environment must always be carried out. Over the next year, through a series of preliminary investigations at sea and on land, NIRAS’s experts will help assess the potential environmental impact, that an offshore wind farm near the Danish isle Hesselø may have.

April 1, 2021
  • SDG: #7, #14
  • SECTORS: Environment and Ecology, Offshore Wind
  • COUNTRIES: Denmark
  • CLIENT: Energinet

Green conversion of energy systems is one of the most important keys to slowing down global climate change. The wind conditions in Denmark make wind turbines an obvious opportunity for green and renewable energy, which is why the number of wind farms continues to increase. Part of the Danish government's Energy Agreement from 2018 is the planned Hesselø Offshore Wind Farm, which according to the Climate Agreement from 2020 will send electricity to the electricity grid in 2027.

Hesselø Offshore Wind Farm will be located in Kattegat by Hesselø Bay approx. 30 km from the north coast of Zealand and approx. 20 km from Hesselø. When the project is completed, it will have a capacity of 800-1,200 MW, which potentially makes the offshore wind farm the largest in Denmark. According to Energinet's website, the park can supply electricity to 800,000 - 1,000,000 households.

How large the wind farm will be, how high the turbines will be, and where exactly the turbines will be located within the designated area, has not yet been clarified. This is decided by the concessionaire who wins the tender to establish and operate the offshore wind farm.

NIRAS is conducting preliminary investigations at sea

Energinet is an independent, public company that owns and develops the electricity and gas network in Denmark. From the Ministry of Climate, Energy and Utilities, Energinet is required to carry out an environmental assessment for the overall plan for Hesselø Offshore Wind Farm. The plan includes both conditions on land and at sea, and the environmental assessment of the plan must shed light on both.

As a foundation for the forthcoming environmental impact assessment (EIA) of the project at sea, preliminary investigations must be carried out at sea, which also helps to reduce risks and uncertainties for the future client. In addition, an EIA of the project on land must be carried out, which includes the construction and operation of high-voltage stations as well as underground cables.

NIRAS, which has a large number of experts with extensive experience in environmental assessments in connection with offshore wind farms, has won the tender to carry out the preliminary investigations at Hesselø for Energinet. As well as preparing an environmental assessment of the plan for Hesselø Offshore Wind Farm and an EIA for the project on land.

The investigations and assessments must be carried out in and near the area where offshore wind turbines and a transformer platform are to be located, as well as in the cable corridor that runs from the wind farm to the coast. In addition, a large number of studies are carried out on land.

At sea, NIRAS in collaboration with DCE/Aarhus University is investigating, among other things, the occurrence of porpoise and seals within and in the vicinity of the area where the offshore wind farm is planned to be established. In addition, the occurrences of animals and plants on the seafloor are examined, just as fish and fishing in the area are mapped. On land, animal and plant life is examined in the area where cables and station facilities are to be established.

Experts in underwater noise

NIRAS is the leading consultant in Denmark within calculation and assessments of underwater noise. Offshore wind turbines are often established by knocking (ramming) them into the seabed. This causes noise under the water, which can affect porpoises and seals that move nearby. In order to be able to assess the extent of impacts from underwater noise, NIRAS calculates the extent and level of noise.

Supporting our clients to realise the potential of offshore wind

Rikke Holm

Rikke Holm

Senior Project Manager

Aarhus, Denmark

+45 8732 3262