Only connect: a North Sea priority

Particularly noteworthy was the awarding to supplier consortia by TenneT of contracts for fourteen 2 GW HVDC offshore connection systems – 28 GW in total, about 30 billion euros worth – as well as significant contracts for the associated 525 kV XLPE HVDC cable.

The 2 GW HVDC system awards were as follows:

• GE/McDermott: HVDC technology for Germany’s BalWin4 and LanWin1 offshore wind connection systems. The onshore DC to AC conversion and grid connection will be at Unterweser.
• Hitachi Energy/Petrofac: contracts for five Dutch HVDC projects to be connected to the grid at Borssele (IJmuiden Ver Alpha, Nederwiek 1), Eemshaven (Doordewind 1 and Doordewind 2) and Geertruidenberg or Moerdijk (Nederwiek 3). This partnership will also realise the German LanWin5 connection, to be connected to the German grid via an onshore DC to AC converter located near Rastede.
• GE/SMOP (Sembcorp Marine Offshore Platforms): contracts for three Dutch projects to be connected to the Dutch grid via conversion technology to be located in the Maasvlakte, Rotterdam (IJmuiden Ver Beta, IJmuiden Ver Gamma and Nederwiek 2).
• Siemens Energy/Dragados: HVDC systems for the German BalWin3 and LanWin4 projects (both to be connected to the onshore grid at Wilhelmshaven) and LanWin2 (to be connected near Heide).

The cable awards for nine of these HVDC projects were announced on 5 May, as follows:

• NKT will realise the connections for Nederwiek 3, landing onshore at either Geertruidenberg or Moerdijk and the connections for Doordewind 1 and Doordewind 2, landing at Eemshaven.
• Nexans has been awarded a contract to provide cables for BalWin3 and LanWin4, to be connected at Wilhelmshaven, as well as for LanWin2, to be connected in the Heide area of Schleswig-Holstein.
• A consortium of Jan De Nul, LS Cable and Denys will realise the cable connections for BalWin4 and LanWin1, both to be connected in the Unterweser area, and LanWin5 to be connected in the Rastede area. (This consortium has also been awarded the contract for the TenneT section of the onshore 525 kV DC corridor NordOstLink in Schleswig-Holstein, Germany, in partnership with 50Hertz.)

Previously, on 3 March, TenneT had announced the cable awards for five of the HVDC connections, “the world’s first 525 kV XLPE HVDC offshore cable systems to connect 2 GW projects”:

• NKT will provide the cable connections for IJmuiden Ver Beta, IJmuiden Ver Gamma and Nederwiek 2, landing onshore at Maasvlakte.
• Prysmian was awarded a contract for the cable connections of IJmuiden Ver Alpha and Nederwiek 1, landing onshore at Sloegebied (Zeeland).

The 2 GW programme

The fourteen HVDC systems are to be realised by 2031. For all the projects, “core components”, meaning the innovative 2 GW converter systems, will be manufactured exclusively at European production sites of the consortium members. “With a contract of this magnitude, Europe will be taking a global lead – in terms of both technology and production – in a key sector of tomorrow’s energy supply,” TenneT believes.

Tim Meyerju¨rgens, COO of TenneT, said: “The North Sea must be developed as Europe’s green power house and quickly connected to the electricity grids on land. We are acting and investing accordingly. Our 2 GW programme will help make green wind energy from the North Sea scalable and more cost-efficient – while continuing to minimise any impacts on the environment.”

“In the global race against climate change, grid expansion must be able to keep pace with the accelerated expansion targets for renewable energies,” observed Tim Holt, member of the Siemens Energy executive board. “Shorter contracting processes, large-scale tenders and standardisation of solutions show how grid operators and manufacturers are already pulling together to get green energy to consumers faster. However, in order for the industry to continue ramping up capacity, all available levers must now be pulled at the policy level as well – from raw material and skilled labour strategies to further streamlining permitting processes at all levels.”

For the cable contracts, the scope of work includes cable design, engineering, production, delivery, project management, onshore, offshore and nearshore installation of the 525 kV HVDC cables and all jointing works in submarine and on land sections.

“The new tender approach speeds up the process,” noted Marco Kuijpers, director, large projects offshore at TenneT, with agreements reached with all cable suppliers in six months. “Such a process would normally take up to 18 months”, he estimated. Also, the contracts have “already initiated serious investments and will give planning security and predictability to our suppliers, who can start investing in extra resources, production facilities, cable laying vessels and trenching tools.”

A major benefit of the 2 GW HVDC concept based on 525 kV is that it requires only one “cable system” – with a cable system consisting of four cables, a ‘plus’ and ‘minus’ pole cable, a metallic return cable and a fibre optic cable – and therefore limits the impact on the environment and the seabed, TenneT points out.

With a firm belief that “the energy transition will only succeed in a spirit of co-operation”, TenneT, together with industry players, initiated R&D in 2020 aimed at developing the 2 GW 525 kV HVDC grid connection standard.

With twice the capacity of previous HVDC offshore connection systems, the new 2 GW standard necessitates an offshore HVDC cable system operating at 525 kV and uses innovative extruded types of insulation. The certification of cable suppliers in 2022 was a result of the “constructive and intensive dialogue between TenneT and the relevant market parties involved”, with the collaboration providing insights as to “the required functionality and performance of this innovative HVDC system.”

With its 2 GW programme, TenneT says it, together with leading global providers in the industry, has developed effectively a new global standard for offshore wind grid connection systems.

Big expansion plans for offshore wind

In the context of increasingly ambitious plans for offshore wind capacity expansion worldwide, not least in Europe, such a standard looks timely.

On 24 April, nine European countries (Belgium, Denmark, France, Germany, Ireland, Luxembourg, the Netherlands, Norway and the UK) meeting at the North Sea Summit in Ostend, signed the Ostend Declaration, undertaking to increase their joint offshore wind capacity to 300 GW by 2050. This new declaration can be seen as superseding the Esbjerg Declaration, signed at last year’s North Sea Summit by Belgium Denmark, Germany and the Netherlands.

The Ostend declaration includes the following goals for offshore wind:

• Belgium plans to establish 6 GW of offshore wind capacity by 2030 and 8 GW by 2040.
• Denmark will enable the deployment of at least 5.3 GW total offshore wind capacity in the North Sea by 2030, with a view towards up to 35 GW in.the North Sea by 2050 and potentially more depending on European demand for green power.
• France aims at having at least 2.1 GW of offshore wind by 2030 and 4.6-17 GW by 2050 in the North Sea and Eastern Channel.
• Germany will have at least 26.4 GW of offshore wind in the North Sea by 2030, and plans to install 66 GW by 2045.
• Ireland hopes to have at least 4.5 GW of North Sea offshore wind capacity by 2030 and 20 GW by 2050.
• Luxembourg aims to contribute to the offshore wind targets set out in the declaration via financial participation in North Sea offshore wind projects.
• Norway aims to establish at least 3 GW of offshore wind by 2030, including 1.5 GW of floating wind and will award areas that are suitable for 30 GW offshore wind by 2040.
• The Netherlands plans to establish about 21 GW of offshore wind capacity by 2030 or thereabouts and is investigating whether 50 GW in 2040 and 72 GW in 2050 are feasible targets considering physical space available, ecological impact and electricity demand.
• The UK aims to have up to 50 GW of offshore wind by 2030. This will include up to 5 GW of floating wind. The UK also aims to establish at least 18 GW of interconnection capacity by 2030.

The Ostend Declaration also lists North Sea offshore wind projects that the signatories are working on, as follows:

• Belgium, Denmark, Germany and the Netherlands are aiming to develop the first interconnected system of energy islands and clusters in the North Seas, by the mid-2030s, thereby contributing to establishment of the first European offshore green power hub, combined with an increasingly meshed offshore grid in the region. These countries invite further countries to join this system.
• Belgium is establishing what it believes is the world’s first offshore energy island, an energy hub combining offshore wind generation and cross-border interconnection.
• Belgium and Denmark are working closely together on hybrid (aka multipurpose) renewable energy connection projects, including the “TritonLink” connecting the Danish Energy Island and Belgium’s Princess Elisabeth Island.
• Belgium and the Netherlands are researching the feasibility of an additional offshore hybrid interconnector between the two countries.
• Belgium and the UK are working on a hybrid interconnector “Nautilus”. Hybrid denotes that the interconnector will connect offshore wind farms as the grids of the two countries.
• Denmark also has ambitions to establish a “world first” energy island in the North Sea with an initial capacity of at least 3 GW offshore wind by 2033 and connections to Belgium and Denmark.
• Denmark and Belgium intend to work together on investigating a second phase of co- operation on connections between the Danish and Belgian energy island in the North Sea after 2033.
• Denmark and the Netherlands plan to explore how to connect the energy island in the Danish Economic Exclusive Zone to a Dutch energy hub, including consideration of offshore renewable hydrogen production.
• Denmark and the UK plan to co-operate on offshore wind development and related areas through knowledge exchange and co-operation on deployment of offshore energy infrastructure including but not limited to offshore wind, interconnection, energy islands/ multi-purpose interconnection, renewable hydrogen and carbon storage.
• Germany plans to initiate the development of large-scale demonstration projects for offshore renewable hydrogen production, with a total capacity of 1 GW. First auctions will take place within this year.
• Germany and Denmark have already developed a first of its kind hybrid offshore wind co-operation project, the Kriegers Flak Combined Grid Solution (which connects the grids of the two countries, as well as providing grid connections for offshore wind farms) and will co-operate on the Bornholm Energy Island, establishing 3 GW of offshore generation capacity in the Baltic Sea, with a hybrid interconnector to Germany and a transmission connection to Zealand (Denmark).
• Germany together with Denmark and the Netherlands is exploring the connection of offshore wind farms in the German exclusive economic zone to offshore wind farms in Denmark and the Netherlands, including an interconnector to the Danish Energy Island, as well as the potential for collaborative development of further hybrid renewable energy projects in the North Sea.
• Germany and the UK are working together to identify prospects for co-operation on hybrid projects in the North Sea providing both offshore wind connections and grid interconnectors.
• Ireland and France are actively moving towards the completion of the Celtic interconnector, with construction works to start this year.
• Ireland and the UK plan to explore opportunities for co-operation in the development of further interconnection between the single electricity market on the island of Ireland and Great Britain, including hybrid/multi-purpose interconnector projects.
• The Netherlands is working on an offshore energy infrastructure plan, which includes identifying areas where windfarms are to be located, where energy hubs and (hybrid) interconnectors are to be established and how much electricity and renewable hydrogen should be produced between 2030 and 2050. Also, to stimulate the development of offshore hydrogen production, the Netherlands plans to facilitate two demonstration projects: one pilot of <100 MW to be in operation by 2030 and one demonstration project of about 500 MW to be completed by 2031 or thereabouts. After this demonstration phase it is expected that large scale renewable hydrogen production will take place offshore, growing eventually to GW scale.
• The Netherlands and the UK are working together to facilitate a multipurpose (aka hybrid) interconnector, called “LionLink” (previously known as EuroLink), connecting the Dutch and UK grids, but also providing wind farms with connections to the grids of both countries. The project has been described as “the first step in the journey to a more interconnected North Sea.”

Meanwhile, Hitachi Energy and WindEurope have published a new report that shows Europe needs to invest hugely in offshore grids to accommodate new offshore wind farms and that the development of a so-called meshed grid will be essential for Europe’s offshore wind development. These are clusters of offshore wind farms with fewer cables connected to the shore that can route power to two or more national grids.

The development of offshore grid infrastructure has been relatively unco-ordinated until recently. Wind farms generally have been connected to one connection point with little co-ordinated planning for future development. Subsea interconnectors are also primarily used to connect only two separate national transmission systems. This is starting to change, say the report’s authors.