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Frequently Asked Questions

The wind farm

Hollandse Kust Noord will be located 18.5 kilometres off the west coast of the Netherlands at Egmond aan Zee.

The wind park
Hollandse Kust Noord is located 18.5 kilometres off the west coast of the Netherlands. The total surface area of the wind farm (including maintenance and safety zones) is 125 kmĀ². CrossWind plans to have an installed capacity of 759 MW, generating at least 3.3 TWh per year. This equals enough renewable electricity for more than 1 million Dutch households.

CrossWind will install 69 wind turbines, each with a capacity of 11 MW. Most of these wind turbines will be more than 1 km apart.

The government has determined that Hollandse Kust Noord may have a maximum of 100 wind turbines with a maximum tip height of 251 metres above sea level and a minimum capacity of 6MW. By opting for larger wind turbines, fewer will need to be installed. As a result, we will increase the efficiency of the wind farm, reduce costs and limit the effects on nature.

When a wind turbine extracts energy from the wind, it leaves a wake of lower wind speeds. This reduces the power of all other wind turbines. In other words: wind turbines capture each other's wind. This is known as the 'wake effect'. To a certain extent, we are already minimising this effect through the layout of the wind turbines in the wind farm.

An innovative solution is to control the wind turbines in a smart way by giving them a yaw error for certain wind directions. This slightly reduces the power of a single wind turbine, but a yawed rotor also pushes the wake away from the wind turbines that are downwind; this results in a higher total capacity. Together with TU Delft and its partners, we are looking at smart control technology based on real-time data to reduce the wake effect across the entire wind farm. This is one of the innovation projects that CrossWind is carrying out.

Innovation Wake Effect

The wind turbines have a tip height of 225.5 metres and a rotor diameter of 200 metres. The blades of the wind turbines are 97 metres long. This tip height falls within the bandwidth from the environmental impact assessment; this states that the tip height may be between 189 and 251 metres.

The turbines
The wind speed is not always the same everywhere. Nevertheless, the wind farm should preferably supply a constant, stable amount of green energy. This means that the wind turbines must be able to respond flexibly to circumstances. CrossWind's wind turbine supplier, Siemens Gamesa Renewable Energy (SGRE), is leading the way in adding flexibility at a scale in which every second counts. The aim is to ensure that the wind turbines become more self-regulating based on real-time data, in order to respond to changing circumstances within seconds. In this way, we will also help to keep the electricity grid stable in the future.
Visibility of the wind farm from the coast depends on the circumstances. These include weather conditions such as fog or a clear day. But the time of day and the season also play a role in visibility.

Building the wind farm

Before we can start construction, various preliminary studies and investigations are required. Examples include a preliminary study of the seabed and research into possible unexploded explosive objects on the seabed (UXO research). These preliminary studies and investigations have now been carried out.

In addition, we have made agreements about various aspects of the construction in consultation with the Ministry of Public Works and Water Management, State Supervision of Mines* and the Coast Guard. This includes a pile-driving plan, a layout plan, a nature-inclusive plan, an emergency response plan and a maintenance plan.

*State Supervision of Mines (SSM) is a government agency that is committed to human safety and the protection of the environment in energy production and the use of the subsurface.

Construction started on 17 October 2022 with the installation of the first monopile; the foundation for the wind turbines.
Construction work will continue 24 hours a day, 7 days a week.
We consider life safety and the safety of the environment extremely important and weather conditions can adversely affect safety. As a result, we will not always be able to work in bad weather. For example, when waves are too high, it is not possible to sail safely at sea. And if wind speeds are too high, we cannot safely lift and install a turbine with the cranes on the ships. Specific weather limits apply to each activity.
Building one wind turbine at sea takes about one day. This includes installing the tower, the nacelle and the three blades. This is preceded by the installation of the foundations, which also takes about one day per wind turbine.
We will install the wind turbines according to a timetable that has been agreed with the Ministry of Public Works and Water Management and runs from mid-October 2022 to the end of 2023. The installation sequence of the wind turbines according to this timetable follows the cabling that connects the wind turbines to TenneT's high-voltage grid. In this way we can commission the wind turbines in an efficient manner.

During the construction work, the wind farm has been designated by the government as a construction zone and will therefore not be accessible to shipping and recreational vessels.

There is also a chance that pile driving noise will be audible along the coast during work on the foundations. We adhere to the noise limits as set down in the building permit. We continuously measure actual noise emissions during the work to ensure that we operate within the applicable and agreed limits.

We expect to complete the construction work by the end of 2023.

Technical questions about the wind farm

CrossWind and TNO will experiment with floating solar panels (0.5 MW) next to the wind turbines as part of the innovation projects in the wind farm agreed with the government. The solar panels will help to generate extra green power when the sun is shining, on top of the power production of the wind turbines. The solar panels will also provide electricity if there is not enough wind. This will result in a more constant energy production. In addition to increasing the capacity per square kilometre of wind farm, we will also increase the utilisation of the grid connection with a combination of these technologies.

An offshore wind farm basically consists of five parts:

1. Sea cables that connect the wind turbines to each other and to TenneT's high-voltage grid. The Twentse Kabel Fabriek (TKF), based in Lochem, is supplying the sea cables for Hollandse Kust Noord.

2. The foundations of the wind turbines, which are anchored in the seabed. These foundations, also known as monopiles, consist of steel plates that have been rolled and welded together by Sif in Roermond and at the Maasvlakte in Rotterdam. In addition to the monopiles, other steel structures are also needed on the foundations to make them accessible for maintenance of the wind turbines. These constructions are made by Amicon in Sneek and Marketex in Estonia.

3. The grey-white towers that stand on the foundations and support the wind turbines are also made of welded steel plates. These towers are manufactured in Denmark by Welcon, a sub-supplier of Siemens Gamesa Renewables.

The nacelles are supplied by Siemens Gamesa Renewables. These nacelles are made of various materials that are brought from all over the world to Cuxhaven in Germany for assembly of the nacelle there.

4. The blades of the wind turbine are mainly made of fiberglass, balsa wood and epoxy, which as a whole is strong enough to transfer the wind forces to the nacelle. These blades are produced by Siemens Gamesa Renewables in Aalborg, Denmark.

Power supply

CrossWind plans to achieve an installed capacity of 759 MW. This equates to a production of at least 3.3 TWh per year. This annual energy production will fulfil some 2.8% of the electricity demand in the Netherlands and is equivalent to the energy consumption of approximately 1 million households.
After the construction phase, the operational phase of the wind farm will commence. In this phase, various tests are carried out over several months. If these tests are successful, we will start connecting the wind turbines to TenneT's 'offshore power socket'. From here, the green electricity goes via the offshore grid to the onshore high-voltage grid.

Animals and Marine life

Marine life may also experience noise nuisance during pile driving and we take measures to limit this.
During the pile driving, we use the best available techniques to keep the nuisance to marine life to a minimum. For example, during pile driving we use a hydro-sound water damper, which dampens the underwater noise, and a bubble curtain. This is a curtain of air bubbles between the monopile and the immediate underwater environment. During the work, the noise levels will comply with the provisions of the Wind Farm Site Decree.

The arrival of the wind farm will affect the habitat of birds, bats, fish and marine mammals. That is why we adhere to the HKN Permit requirements and the Wind Farm Site Decree. We apply measures for birds and bats to limit any adverse effects, such as shutting down the wind turbines under certain circumstances. In order not to unnecessarily disturb fish and marine mammals, we adhere to a maximum noise level while pile driving the foundations of the wind turbines.

Permits and Experience

CrossWind needs various permits to build and operate the wind farm. Some examples:

- The most important one is the permit for the construction and operation of the wind farm. This permit was granted to CrossWind when we won the Hollandse Kust Noord tender.

- This construction and operating permit includes references to the regulations contained in the 'Kavelbesluit Hollandse Kust Noord' (Hollandse Kust Noord Wind Farm Site Decree). These regulations are based on the specific area characteristics of the plot. The permit also states that CrossWind must comply with the general rules that apply to offshore wind farms. These are described in the 'Water Decree' ('Waterbesluit').

- In addition, CrossWind must comply with the working conditions and working hours legislation that apply on the North Sea. We must also meet the conditions set by the Ministry of Public Works and Water Management, State Supervision of Mines and the Coastguard; these conditions are documented in the plans that must be approved before the start of construction work.

CrossWind is a joint venture of Shell and Eneco. As two leading Dutch energy companies, we combine the experience, expertise and financial strength needed to develop Hollandse Kust Noord; a subsidy-free offshore wind farm and the first offshore wind farm with a range of innovations aimed at system integration.

Shared use

During the construction of the wind farm, the area will be completely closed off for safety reasons. When the construction work has been completed, the wind energy area will be reopened for the passage of small vessels and shared use.

The government - in close collaboration with CrossWind and various stakeholders such as fisheries and nature organisations - is investigating the possibility of shared use of the area between the wind turbines when operating. For example, the space between the wind turbines is very suitable for sustainable forms of fishing that do not disturb the sea bed (such as seaweed and oyster collection) and innovative forms of energy generation, such as floating solar panels. The government is proposing a special 'area passport' for Hollandse Kust Noord, which will include the most suitable forms of shared use for the area.

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