London — A series of energy islands in the North Sea would be preferable to one large one, Dutch, Danish and German partners in the North Sea Wind Power Hub consortium said Wednesday following a two-year assessment phase.
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While the islands may be smaller than initially thought, the long-term outlook for offshore wind has improved since March 2017 when transmission system operators Tennet and Energinet first agreed to look at the concept.
"As the North Sea has great potential for offshore wind power, the implementation of 180 GW can be achieved by 2045 by the consortium's approach," it said.
Island power hubs coupled with power-to-gas facilities could further improve the economics of the concept, the consortium said.
"Initial study and preliminary test results confirm the proposed project's technical and economic feasibility," it said adding that first hubs could be operational in the 2030s with project development times of at least 10 years.
The consortium, including power and gas grid operators as well as the Port of Rotterdam, has been conducting studies and engaging with policy makers on hub-and-spoke projects that combine on- and offshore grid connections alongside electrolysis facilities for production of green hydrogen.
North Sea offshore wind capacity of 180 GW could generate 770 TWh a year. That is close to the combined annual power demand of Germany, the Netherlands and Denmark, and would put a huge strain on transmission as well as downward pressure on power prices if not combined with sufficient storage and interconnector facilities. Studies show that up to 140 TWh seasonal storage and 50-80 GW transmission capacity would be needed.
By 2030, there could be 50 GW offshore wind installed in the North Sea, of which nearly half is planned in UK waters.
German, Dutch and Danish offshore plans alone are on track for over 30 GW installed by 2030 with the consortium saying that a first hub would need to fit into current grid planning.
The consortium remains open for new partners to join in the future with initial discussions with UK authorities and National Grid.
"This is as a link that needs to be preserved," Tennet's project leader Michiel Muller said, but added that the UK has not signed yet the North Sea Energy Cooperation.
With the available offshore area in the southern part of the North Sea limited to about 14,000 sq km (5,405 square miles), assuming exclusion of current use areas, up to 90 GW of new capacity was seen as feasible under one of six concepts.
Co-use of areas such as decommissioned oil and gas rigs, meanwhile, would unlock the North Sea's full potential, it said.
Specific proposals range from a sand island (12, 24 or 36 GW) with an approximate construction time of eight years, to a caisson island suitable for smaller hubs of 6 GW with an estimated three-year construction period.
The consortium has studied locations in Dutch and Danish waters using various electrical and hydrogen connection configurations. All show wind yield potential of 48%-54%.
As next step towards implementation, the consortium is inviting the Dutch, Danish and German governments as well as the European Commission to consider setting up a cross-governmental consultation.
Denmark's new government has mentioned plans for an offshore wind island of up to 10 GW to be developed in its ambitious 2030 climate plans, Energinet Chief Technology Officer Torben Glar Nielsen said.
|North Sea Offshore Wind Hub: Key Scenarios|
|Caisson Island||Sand Island||Platform|
|Water depth||<25 m||<40 m||<45 m|
|Construction time||3-4 years||6-8 years||3-4 years|
|Size limitations||6 GW||36 GW||2 GW|
|Phasing & modularity||No||No||Yes|
|Wind Yield Potential Study (by cluster size/location)|
|Cluster Size/Location||1 (NL Dogger Bank)||2 (NL South of Dogger Bank)||3 (DK West of Jutland)|
--Andreas Franke, firstname.lastname@example.org
--Edited by Jonathan Dart, email@example.com