Horns Reef 3

Location

Horns Rev 3 is located in the North Sea, approximately 25-40 kilometers off the northwest coast of Denmark, in an area known for its windy climate throughout the year. It is situated close to the existing Horns Rev 1 and Horns Rev 2 offshore wind farms.

Capacity and Impact

The wind farm has a total installed capacity of 407 MW, which is expected to boost Denmark's electricity production from wind by around 12%. This capacity is sufficient to cover the annual electricity consumption of approximately 425,000 Danish households.

Turbines and Infrastructure

• The wind farm is equipped with 49 MHI Vestas V164-8.3 MW turbines. Each turbine has a rotor diameter of 164 meters, with 80-meter-long blades, and a total height of 187 meters to the blade tip. The turbines weigh approximately 1,500 tonnes each, including the foundation.
• The turbines are supported by steel monopile foundations, each up to 50 meters long and 6.5 meters in diameter, coated with protective paint and installed with sacrificial anodes to prevent corrosion.

Construction and Timeline

• The construction of Horns Rev 3 began in May 2017 with the installation of the foundations. All 49 foundations were in place by January 2018.
• The installation of the transition pieces and the turbine towers followed, with the first turbine installed in July 2018. The wind farm started generating electricity in December 2018 and was fully commissioned by August 2019.

Grid Connection

• The electricity generated by the turbines is transmitted to an offshore substation through inter-array cables. The voltage is stepped up to 220 kV by transformer platforms.
• The power is then transferred to an onshore substation at Houstrup Beach via a 220 kV export cable. From there, it is connected to the existing electrical transmission network through additional substations and power lines.

Environmental and Social Impact

• The project was assessed for its environmental impact, including air pollutant emissions during construction, operation, and decommissioning phases. The assessments were conducted with reference to national and international guidelines.
• The wind farm is expected to contribute significantly to Denmark's transition to a renewable energy system, aligning with Vattenfall's ambition to enable a fossil-free living within one generation.

Economic and Employment Impact

• The project involved an estimated investment of £1 billion ($1.3 billion) and generated around 7,000 jobs during the construction phase, according to the Danish Ministry of Finance.

Key Players Involved

• Vattenfall: The Swedish state-owned energy company is the owner and operator of the wind farm. Vattenfall won the concession to construct and operate Horns Rev 3 in February 2015.
• MHI Vestas: Supplied the 49 V164-8.3 MW turbines for the project.
• GeoSea: Responsible for the manufacturing, transport, and installation of turbine foundations.
• Energinet.dk: Collaborated with Lloyd’s Register on noise mitigation measures and grid connection installations.
• ABB and Prysmian Group: Supplied the 245 kV HVAC power cable connection.
• Blue Water: Handled port logistics and the transportation and storage of transformer units.

Additional Context

• Horns Rev 3 is part of Vattenfall's broader strategy to increase wind energy capacity in Denmark. Alongside Horns Rev 3, Vattenfall is also developing the offshore wind farms Vesterhav Syd & Nord and Kriegers Flak, which will collectively add more than 1.4 GW of wind energy capacity to the Danish energy system.