Thor is an offshore wind farm planned to be developed in the Danish North Sea around 20km from the coast. The wind farm is named after Thorsminde, the nearest village on the shore.

As part of the 2018 Energy Agreement, three large offshore wind farms will be built in Denmark before 2030. The Thor Wind Farm is the first of the three offshore wind farms.

In January 2022, German multinational energy company RWE signed a concession agreement with the Danish Energy Agency (Energistyrelsen) to develop the Thor offshore wind farm and operate it for 30 years.

With a planned capacity of up to 1,000MW, the wind farm will supply electricity to around 1 million households in Denmark. It is expected to be fully commissioned and connected to the grid no later than 2027.

The project will entail an investment of DKK15.5bn ($2.06bn).

Location and Site details

Thor Offshore Wind Farm project will be established at least 22km off Thorsminde on the west coast of Jutland. The water depth in the region is around 28m on average.

After site investigations, Danish Energy Agency reduced the size of the site from 440km2 to 286km2 in May 2021 due to factors such as stone reefs, raw material, birds, cumulative visual aspects, fishing, navigation safety and visual impact.

RWE will use the Port of Thorsminde to conduct operations and maintenance of the wind power project. For this, a letter of intent (LoI) was signed by the two companies in April 2022.

The port will offer RWE the shortest sea and fastest air routes to Thor Offshore Wind Farm. It will be used to transport construction crews and other components for the project as well as support the first survey works.

RWE aims to establish its base at Thorsminde by early 2023, while the service station at the port is expected to be fully operational by 2026.

Thor Offshore Wind Farm Project details

The project will feature around 67-72 wind turbines, each with a power generating capacity of 14-15MW. The RWE-owned project will leverage a monopile FOU concept to install the wind turbines.

The substations for the project will be located both onshore and offshore.

A 220 Kilovolt (kV) station will be built as a part of the 220/400 kV conversion of an existing 400kV station point of connection (POC) in Idomland. The station will be connected with a new station of 220Kv (POC) at Volder Mark through 28km long underground cables.

At the Volder Mark station, which is located 4km away from the coastline, electricity produced by Thor will be delivered to the grid.

Once fully operational, Thor will be the largest offshore wind farm to date in Denmark.

Soil investigation

In July 2022, RWE commenced soil investigations off the Danish west coast for Thor offshore wind farm.

Three research vessels will be used to procure geotechnical data to support the design, installation, and fabrication of the foundations of the project along with cables.

Fugro Scout, a geological research vessel, is involved in drilling and testing at prospective wind turbine locations.

Normand Mermaid and Energy Scout research vessels will be used to determine certain parameters for the soil behaviour under the turbine loading area, and to enable the design, installation, and protection of the inter-array cables and main export cable respectively.

The programme will also include conducting thermal conductivity tests of the soil.

Contractors Involved

In April 2022, RWE signed a grid connection agreement with Danish grid operator Energinet.

As part of the agreement, Energinet will develop and operate the onshore grid connection from the second onshore substation to the overall transmission grid. The scope of work will include building the two 220kV electrical substations.

The company has also signed an agreement with the Port of Thorsminde authority to use it as a base for maintenance and operations.

The geotechnical site investigations for Thor offshore wind farm development will be conducted by vessels from Fugro.