Van Oord-Led Consortium Wins Borssele Demo Site Tender

Two Towers BV, a consortium comprising Van Oord Renewable Finance, Investri Offshore and Green Giraffe Holding has won the Dutch tender for the fifth site at the Borssele zone, designated as the demonstration site for innovations in offshore wind.

One of the innovative aspects of the winning project is wind energy infrastructure that stimulates the formation of oyster beds and improve the ecosystem of the North Sea.

The consortium will also test a mounting system between a tower and foundation, to make the wind turbine structure last longer and require less maintenance, as well as an advanced coating solution that better protects wind turbines and thus makes them more cost-efficient in terms of O&M.

Although the tender procedure was coordinated with the sector in advance, the only bid received was that of Two Towers. The challenging nature of such innovation sites and the strict requirements for being granted a subsidy may have played a role in this matter, according to RVO.nl. “Nevertheless, Two Towers managed to submit an excellent tender,” RVO.nl pointed out.

For the testing of its innovations, the consortium will receive an innovation subsidy of up to EUR 15 million. In addition, it will also receive a maximum subsidy of EUR 35 million for the electricity supplied.

The Borssele V offshore wind farm is expected to start producing power in 2021, and will provide enough clean electricity to power more than 25,000 households.

Win-win solution with oyster beds

Due to the absence of soil-disrupting activities such as trawl fishing, new ecosystems can develop in the vicinity of wind turbines, the Netherlands Enterprise Agency (RVO.nl) writes. In order to stimulate this natural process, the Borssele V innovation site will house oyster beds, which prevent erosion of the soil around wind turbine foundations and help restore the marine ecosystem in the North Sea.

On the seabed, rocks of various types and sizes will be placed to limit the flow of water and the stirring of the soil, so that an ideal habitat for oysters is created. The rocks will be enriched with calciferous shell material to have a good basis for the oysters, which will then be added at different stages of life, ultimately resulting in them multiplying and spreading through the North Sea.

Good news for the oysters (if not for gourmands): these oyster beds will not be harvested. Instead, they will remain on the reef to allow further replenishment of the seabed and development of the ecosystem.” – RVO.nl

With a novel clamping connection between a foundation and tower, the consortium aims to make the construction of wind farms easier and cheaper, with an aluminium-based protection increasing life expectancy of the tower and requiring less maintenance.

In addition, an innovative coating system will be used to combat corrosion in an efficient, safe and environmentally friendly manner, which will ultimately increase the lifespan and the return on investment, according to RVO.nl.