In the world of renewable energy, there is no single solution: multiple sources have to be combined. Success depends on the international networks that will be established in the future to connect sources and users. How can we tackle this challenge? And what sources should we focus on?

Affordable sustainable energy

In 2013, more than 40 organisations signed an Energy Agreement in which the Dutch government and business committed themselves to the transition to sustainable energy supplies. An important component of the Energy Agreement consisted of targets for wind energy, including a short-term goal to increase offshore wind power from 1,000 MW to 4,500 MW. To achieve that goal, more than four hundred wind turbines will have to be installed offshore. The planned wind farms - which have to be in place by 2023 and which will be among the largest in Europe - will supply five million households with energy.

The good news is that these wind farms can be built for far less money than the government's initial budget. The estimated costs will be reduced from €18 billion to €6 billion thanks to the application of new technologies. Partly due to research conducted by Deltares, the offshore wind farm zone that will deliver the cheapest electricity will be Borssele.


Deltares was involved in the programme for the Borssele Wind Farm Zone at an early stage. In order to ensure the bidding process for the construction of the new wind farms is competitive, the Netherlands Enterprise Agency ( is collecting site data about the new wind farm zones. is an agency of the Ministry of Economic Affairs and is commissioning a range of studies. It will then make research results available to interested parties. Deltares has been involved in mapping out a large proportion of the site data relating to the Borssele Wind Farm Zone using a unique combination of technologies and models. For example, we identified the hydraulic boundary conditions (metocean conditions, such as wave heights and flow rates) using numerical models. During the same phase, we made forecasts of changes in the seabed due to mechanical forces exerted by currents and waves in Borssele throughout the lifetime of the future wind farm. This meant making extremely wide-ranging analyses of the data to describe changes in the seabed in recent decades. In that way, it is possible to determine, for example, the best locations for foundations or cables. Deltares was also involved during the tendering phase, helping different consortiums to use the data about the location and to optimise their specific projects.

In addition to the wind farms themselves an offshore power grid will be built. In the past, developers had responsibility for the grid connection linking their wind farms to the mainland, using long export cables; for the new wind zones, TenneT is responsible for grid connection and will build large offshore transformer platforms to which the wind farms can be connected. TenneT will be building two of these 'offshore sockets' in Borssele. For the stability of the foundations, it is important to know how much erosion ('scour') occurs in the bed around the foundations. Deltares simulated scour and the required protection in a scale model in one of its unique hydraulic facilities, the Atlantic Basin, so there will now be stable foundations throughout the lifetime of the wind farm.

Deltares is playing a key role in the spectacular reduction in the costs of offshore wind.
Tim Raaijmakers en Greta van Velzen
Deltares experts Offshore Engineering
2016 was the year in which offshore wind energy made its breakthrough, both in the Netherlands and internationally. The pioneering work of Deltares has made a major contribution to this breakthrough.
Frank van Erp
Senior Advisor Renewable Energy at Netherlands Enterprise Agency (RVO)

For this project Deltares has collaborated with the following partners:

  • Rijksdienst voor Ondernemend Nederland
  • Tennet
Energy tim

Want to know more about this project?

Tim Raaijmakers
Expert Hydraulic Engineering
  • +31 (0)64 69 11 177