With its relative shallowness the Dogger Bank zone has long attracted special interest in the North Sea. Not surprisingly it is an obvious site for offshore wind and several large gigawatt scale wind farms, including some of Britain’s largest, are under development there.
Now it is also the proposed site by a consortium of transmission system operators (TSOs), TenneT from the Netherlands and Germany and Energinet.dk from Denmark, for the construction of a central wind power hub based on one or more artificial islands.
North Sea Wind Power Hub
The North Sea Wind Power Hub is proposed to operate on the ‘hub and spoke’ principle, with as many as 10,000 wind turbines – and possibly as much as 100,000MW in capacity – from North Sea wind farms connected to the artificial ‘power link islands’. From these, the generated wind energy would be distributed and transmitted over DC lines to the surrounding North Sea countries – Belgium, Britain, Denmark, Germany, Netherlands and Norway.
Location of proposed North Sea Wind Power Hub
With the transmission cables simultaneously functioning as interconnectors between the countries, they also would be enabled to trade electricity.
According to statements from TenneT and Energinet.dk, the North Sea Wind Power Hub is founded on the need for cooperation between countries to achieve a sustainable and stable energy system with high levels of wind and solar energy, beyond what can be accomplished by individual countries on their own.
As such, the Hub provides a point of departure for “a joint European approach up to 2050 and focuses specifically on developing the North Sea as a source of and a distribution centre for Europe’s energy transition.”
“This project can significantly contribute to a completely renewable supply of electricity in northwest Europe,” says Mel Kroon, CEO of TenneT in the statement. “TSOs are best placed to play a leading role in the long-term development of the offshore infrastructure.”
Peder Østermark Andreasen, CEO of Energinet.dk, adds: “Offshore wind has in recent years proved to be increasingly competitive and it is important to us to constantly focus on further reduction in prices of grid connections and interconnections. We need innovative and large-scale projects so that offshore wind can play an even bigger part in our future energy supply.”
Power link islands
According to the company statements the Dogger Bank location of the proposed North Sea Wind Power Hub satisfies a number of requirements – these including in addition to the relatively shallow water, the optimal wind conditions and its central location (i.e. the same factors that make the zone so suitable for offshore wind farms).
“In short, Power Link islands in the middle of the North Sea offers everything necessary to make offshore wind energy a success,” says the statement.
Artists’ impressions show the proposed island(s) to be about 6km2 in size, which would provide the space for connecting approximately 30GW of wind capacity and to include a harbour and runway for a small passenger plane along with other facilities for the staff that would reside there.
At least according to TenneT’s initial thinking when the company first announced the initiative in 2016, they would be modular in concept and thus expandable with the addition of one or more modules.
However, no mention has been made of the form they will take or the engineering challenges involved in the construction and enabling them to withstand the local storm conditions. Nor has an estimate of their cost been made available.
The trilateral agreement between the three TSOs was signed on March 23. Discussions with other potential partners, including other North Sea TSOs and infrastructure companies, are ongoing. The goal is to achieve a multi-party consortium to realise the project, which is envisaged for building in the 2030 to 2050 timeframe.
North Sea grid
The North Sea region is considered an ‘energy hotspot’ for several reasons. One is the offshore wind potential. Almost three-quarters of Europe’s offshore wind installations are in the North Sea and for example in the last year over 96% of the region’s new offshore wind capacity was there, according to WindEurope’s 2016 statistical review
Another is the potential to bring in new technologies, such as power-to-gas, hydrogen storage and carbon capture and storage using the decommissioned oil and gas wells, platforms and pipelines that otherwise would be removed.
The development of a North Sea grid linking the surrounding countries has been a long standing policy objective of the European Union.
Last year these countries signed an agreement on cooperation, with a focus on four specific work areas pertaining to the further deployment of offshore wind and country interconnections: maritime spatial planning, regulation, a support framework and finance and standards and technical rules. The outcomes of these programmes are due by 2019.
However, a recent survey of stakeholders by Ecofys and Navigant has found that while a North Sea grid could bring significant financial, technical, and environmental benefits, there are considerable challenges to overcome, not only around regulation and financing but also relating to uncertainty over the risks and impacts.
Indeed some, at least from the economic perspective, are unclear of the need for such a grid. If tangible progress is to be made there is a real need for increased engagement, the white paper states.