The Borkum Riffgrund 3 project will be located adjacent to the Borkum Riffgrund 1 and 2 wind farms, which are also owned by Ørsted. Credit: Ørsted.
The Borkum Riffgrund 3 will be powered by 83 SG 11.0-200 DD offshore wind turbines supplied by Siemens Gamesa. Credit: Siemens Gamesa Renewable Energy.
The construction of the DolWin epsilon offshore converter platform commenced in December 2020. Credit: TenneT Holding.

The 900MW Borkum Riffgrund 3 offshore wind farm is proposed to be developed by Danish energy company Ørsted.

The offshore wind project was approved by the German Federal Maritime and Hydrographic Agency (BSH) in October 2021. The final investment decision is expected by the end of 2021, while the wind farm is expected to become operational in 2025.

Divestment of stake in Borkum Riffgrund 3

Ørsted signed an agreement to divest 50% of its ownership in Borkum Riffgrund 3 to UK-based fund manager Glennmont Partners for kr9bn ($1.41bn) in October 2021. The project cost includes the acquisition price and funding component. The transaction is subject to approvals and the final investment decision (FID) on the project.

Ørsted will be responsible for developing the project under an engineering, procurement and construction (EPC) contract according to the terms of the agreement. In addition, it will be responsible for operations and maintenance for 20 years.

Borkum Riffgrund 3 offshore wind farm background

Borkum Riffgrund 3 is a combination of three offshore wind projects, namely Riffgrund West 1 (420MW), Borkum Riffgrund West 2 (240MW) and OWP West (240MW). Ørsted secured the right to build the three wind farms in German offshore wind auctions held between 2017 and 2018.

The company clubbed the three offshore wind projects into one and renamed the project Borkum Riffgrund 3 in September 2019.

Borkum Riffgrund 3 location and details

The Borkum Riffgrund 3 offshore wind farm will be located in the German waters of the North Sea, off the coast of Lower Saxony. It will be constructed near Ørsted’s existing Borkum Riffgrund 1 and Borkum Riffgrund 2 wind farms.

Borkum Riffgrund 3 will be equipped with 83 Siemens SG 11.0-200 DD offshore wind turbines, which are based on direct drive technology. Each turbine will have a nominal output of 11MW and feature 97m-long blades with a swept area of 31,400m² (337,986ft²).

Each monopile for the Borkum Riffgrund 3 offshore wind farm will have a length of up to 100m, diameter of 10m and weight of 1,200t. The monopile foundations will be installed at water depths between 28m and 34m.

Power purchase agreements

A ten-year corporate power purchase agreement (CPPA) was signed with Covestro, a high-performance polymer materials supplier based in Germany, in December 2019 for the off-take of 100MW of the output from the Borkum Riffgrund 3 wind farm.

Ørsted signed another CPPA with Amazon to supply 250MW for ten years in December 2020. The CPPA, which is the biggest PPA ever for offshore wind in Europe, will support Amazon’s target of using 100% renewable power by 2030.

German food retailer REWE Group signed a ten-year agreement to purchase 100MW of power from the offshore wind farm in September 2021.

Grid connection

The power generated from the project will be transferred to the grid by the DolWin epsilon offshore converter platform. The 900MW DolWin5 high-voltage direct current (HVDC) transmission system will link the turbines to the DolWin epsilon converter platform using a 66kV connection to transmit three-phase alternating current (AC).

The direct connection between the wind farm and offshore platform will eliminate the need for substations.

The three-phase AC power will be converted into direct current (DC) at the DolWin epsilon platform and transported over 100km through a submarine cable to the landing point in Hamswehrum. A 30km-long land cable will provide the connection between Hamswehrum and the converter station in Emden. The electricity will be converted back into three-phase AC before being fed into the extra-high-voltage grid.

The converter platform will provide accommodation for 50 people and include a helicopter landing pad, crane and lifeboat. The commissioning of the grid connection system is expected in 2024.

Financing for Borkum Riffgrund 3 wind project

Ørsted led the financing package for the project, while Glennmont co-arranged it. The debt facilities will be provided by eight banks, namely Natwest, ING, Bank of China, Santander, Helaba, ABN AMRO, SEB and Siemens Bank.

Contractors involved

Ørsted signed contracts with Bladt Industries and Steelwind Nordenham in September 2021 for the supply of 107 monopile foundations for Borkum Riffgrund 3 and Gode Wind 3, a 242MW offshore wind farm being developed in the German North Sea by Ørsted. Steelwind Nordenham is responsible for the supply of 66 monopiles, while Bladt Industries will provide 41 monopiles.

In October 2021, Jan De Nul Group was contracted to transport and install monopile foundations and an offshore substation topside at the Ørsted Borkum Riffgrund 3 and Gode Wind 3 projects.

Safety science and service provider for the renewables industry UL was awarded a contract to certify turbines and foundations for the project in July 2021.

Siemens Gamesa Renewable Energy was selected as the preferred turbine supplier for the project in March 2020. The preferred supplier award also included a service and maintenance agreement for five years.

Offshore wind energy services company Seaway 7 was named the preferred contractor for the transport and installation of wind turbine generators for the Gode Wind 3 and Borkum Riffgrund 3 wind farms in October 2021. The company will perform the installation using its jack-up installation vessel VIND1.

The DolWin epsilon offshore platform is being developed by TenneT, a European transmission system operator. TenneT selected the consortium of Aibel and Keppel FELS for the offshore grid connection in May 2019. Keppel FELS is responsible for the manufacture of the DolWin epsilon offshore platform steel structure at its shipyard in Singapore. Aibel will install DolWin epsilon with the converter and transformers at Haugesund, Norway, following the completion of the construction.

Hitachi ABB was subcontracted by the consortium to supply the extra-high voltage DC technology to minimise power losses during transmission. Prysmian Group received a contract to supply, install and commission a HVDC 320kV cross-linked polyethylene (XLPE)-insulated submarine and land power cable connection, as well as the associated fibre optic cable system for the Dolwin5 project.

The emergency gensets for the DolWin epsilon converter platform will be provided by mtu, a power products and solutions brand of Rolls-Royce.

German law firm Hengeler Mueller provided advisory services to Ørsted for the stake sale and its financing.