Future offshore wind farms require bold solutions

IJmuiden Ver offshore converter station. Credits TenneT

The Netherlands faces an enormous challenge of producing 49 terawatt hours of electricity from wind turbines at the North Sea by the year 2030. The only solution seems to be ever larger turbines far away from the coast, as was discussed at the National Wind Energy Event April 17 in Rotterdam. But how do we ensure that offshore wind energy remains competitive?

Offshore wind energy in the Netherlands literally has the wind at its back. For example, the 2030 Roadmap by the Ministry of Economic Affairs and Climate Policy aims for no less than 10.6 gigawatts (10,600 megawatts) in the Dutch part of the North Sea. Of this, 3.5 GW must be installed by 2023 and 6.1 GW by 2030. By way of comparison: the four existing offshore wind farms have a combined capacity of 957 MW. So, there’s work to do!
The designated zones for the third generation (2023-2030) of offshore wind farms are ‘Hollandse Kust (West)’ (1,400 MW), ‘Ten Noorden van de Waddeneilanden’ (700 MW) and ‘IJmuiden Ver’ (4,000 MW or 4 GW). The latter’s name (‘IJmuiden Far’) has been chosen aptly, because the location is situated at no less than eighty kilometres from the coast, near the British Exclusive Economic Zone. Here, Swedish developer Vattenfall will build the Norfolk Vanguard and Norfolk Boreas wind farms, both accounting for 1.8 GW.

Enormous distances
Such distances between wind farms and the mainland pose considerable challenges. In the run-up to IJmuiden Ver’ offshore wind farm, which is scheduled to go into production between 2027 and 2030, TenneT is already working on the development of a new generation of 2 gigawatt (GW) transformer stations and 525 kilovolt (kV) electricity cables, in order to get the enormous amount of electricity on land efficiently. “Offshore wind energy is currently showing a paradox,” claims Rob van der Hage MSc, Manager Offshore Grid Development at TenneT NL. “While the costs for construction, operation and investment are steadily decreasing, transport and connection costs are increasing due to longer distances. This can pose a threat to the cost reduction of offshore wind energy.”

For the upcoming wind farms in 2023, TenneT can suffice with transformer stations of 700 MW. However, new solutions are needed for IJmuiden Ver sized wind farms. For example, as grid manager TenneT has calculated, from about 80 kilometres off the coast, DC cables are more efficient than AC cables.

Of course, the Arnhem-based grid operator also takes into account the 10 MW and 12 MW wind turbines that will make their debut in a few years’ time. For example, General Electric is currently building the world’s largest wind turbine, Haliade-X 12 MW, in the port of Rotterdam. This test model will have three rotor blades of 107 metres and a rotor diameter of no less than 220 metres. A test period of five years will start by mid-2019.

Energy islands
Together with Gasunie, Port of Rotterdam and Energinet.dk from Denmark, TenneT has been investigating the feasibility of artificial energy islands in the North Sea since 2016. It goes without saying that these ‘NorthSea Windpower Hubs’ will not be realised overnight, so TenneT and its partners are aiming for 2030 and beyond. The aim of these islands is not only to bundle large quantities of electricity from neighbouring wind farms and bring it ashore in North-West Europe via an advanced network of connectors and cables, but also to use the electricity produced on site for, hydrogen production, for example. In addition, maintenance and assembly of wind turbines could also take place there. Such energy islands do require far-reaching European cooperation. Especially, if in the distant future the entire North Sea is likely to host 150 GW (or more) of offshore wind farms.

For Kees-Jan Rameau, chief strategic growth officer at energy company Eneco, it is important that the price of wind energy continues to fall in the coming years. “At Luchterduinen in 2011, investment costs were 170 euros per megawatt hour. At Borssele 3 and 4, December 2016, this rate had already fallen to 54 euros and the end is not yet in sight. That’s why nowadays, we can build offshore wind farms without government subsidies.”

According to Rameau, this cost reduction can only continue if we succeed in balancing supply and demand of electricity from wind farms at sea. “In 2030, most of the demand for clean electricity will come from industry, approximately some 18 terawatt hour. After all, for their production processes companies will have to switch from natural gas to electrification in the coming years.”

For this view, Rameau gets support from Hans Timmers, chairman of NWEA (Netherlands Wind Energy Association), and Allard Castelein, CEO of the Port of Rotterdam. Rameau: “We are currently building large-scale wind turbines, and also solar panels, without asking if there’s a demand for this electricity by the industry, households or the transport sector. This has to change.”

Coastal areas
According to Rameau, it is also important that the electricity generated offshore is directly transported to the large industries in the coastal areas. In his view, this will prevent billions of euros in investments in new high-voltage lines and onshore grid upgrades. With Tata Steel in IJmuiden, but also with the large petrochemical and process industry in the ports of Rotterdam, Amsterdam, Vlissingen/Terneuzen and Eemshaven, the Netherlands has an excellent position.

Timmers (NWEA) also believes that the national industry is essential for the success – or failure – of offshore wind energy. “If there’s no demand from the industry, then there’s no business case.” Timmers does not foresee any problems with the first 10.6 gigawatts of wind farms at the North Sea. However, situation will be different at around 60 to 75 GW in the year 2050. The ‘Planbureau voor de Leefomgeving’ (Netherlands Environmental Assessment Agency) has calculated this is most likely the maximum capacity of the Dutch Exclusive Economic Zone. Timmers: “That’s about 20 to 25 percent of the total area. At that stage, we have to think very carefully about what the infrastructure at sea should look like, how we are going to get all that electricity on land and what is going to happen with it.”

Although the Netherlands is currently almost at the bottom of the European Union with only 7.28% renewable energy, according to the chairman of the NWEA, we are making up for lost ground in the field of offshore wind energy. “In 2030, The Netherlands will be the third country in the North Sea with a capacity of 10.6 GW, after Great Britain (30 GW) and Germany (15 GW). In addition, we have a strong supply industry that is involved in three quarters of all European wind farms.” Timmers mentions TenneT, SIF Offshore Foundations, Huisman, Royal IHC, Boskalis, Van Oord and Seaway Heavy Lifting as fine examples.

Opportunities for Rotterdam
Allard Castelein of the Port of Rotterdam also sees offshore wind energy as an important tool to become an energy-neutral port in 2050. “We have 200 MW of wind turbines in the port area and can still grow to around 300 MW, but unfortunately there is no more space in our port. That is why we are looking at the North Sea with extra interest. This must become our new national energy province.”

According to Castelein, offshore wind can largely take care of the electrification and sustainability of Rotterdam’s industry. “In the future, the petrochemical and process industry will not only need large amounts of sustainable electricity, but also large amounts of heat of about 1400 degrees Celsius. Offshore wind farms are extremely suitable for converting this electricity into hydrogen via electrolysis, as source for this heat.”
Castelein is convinced that the port of Rotterdam can benefit greatly from offshore wind energy. “Ten thousand jobs will be created in 2020, and ten years later it will be doubled. We must not miss this opportunity!”

This article appeared in Wind Energy Magazine, No. 2, 2019. Text by Bart Stam

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