The North Sea 100GW Vision and Sumitomo Electric’s Role in Power Cables as Strategic Infrastructure

Introduction: Europe’s Offshore Wind Is Moving from “Power Plants” to an International Transmission Grid

Europe’s offshore wind sector is now at a major turning point. Until recently, offshore wind projects were mainly “single-country” projects: each country built wind farms off its own coast and connected them to its own national grid. However, the direction set out at the North Sea Summit in January 2026 goes one step further. Countries surrounding the North Sea—including the United Kingdom, Germany, Denmark, France, the Netherlands, and Norway—are moving toward the construction of a large-scale power grid that combines offshore wind with cross-border interconnectors, with the aim of turning the North Sea into something like Europe’s “clean energy reservoir.”

What deserves particular attention is that these countries are not simply trying to build more wind turbines. They are also seeking to develop high-voltage submarine cable networks connecting multiple countries, enabling offshore wind power to be traded across borders. North Sea countries have indicated their intention to contribute to the deployment of 15GW of offshore wind annually from 2031 to 2040, while transmission system operators aim to identify 20GW of promising cross-border projects by 2027 that could be deployed in the 2030s. This shows that Europe’s power infrastructure is beginning to shift from “national transmission grids” to an “international energy network sharing a common sea area.”

1. The North Sea 100GW Vision: Europe’s Energy Security Itself

At the Hamburg North Sea Summit in January 2026, North Sea countries including the UK confirmed their intention to pursue joint and cross-border offshore wind projects of up to 100GW in the future. Behind this are several challenges: reducing dependence on Russian gas, dealing with high energy prices, and maintaining the competitiveness of European industry. The European Commission also positions the North Sea Summit agreement as an important step toward building a clean, secure, and independent energy system.

The key point of this vision is to use the North Sea not simply as a concentration of wind farms, but as a power stabilization mechanism for Europe as a whole. Electricity generated in windy countries and regions can be transmitted across borders to areas with high demand. In the future, hydrogen production, energy storage, port infrastructure, and offshore substations may also be developed as part of this integrated system. In other words, the North Sea offshore wind grid is not only about power generation facilities. It is also a massive industrial policy covering cables, substations, ports, vessels, maintenance, and workforce development.

According to WindEurope, under the North Sea Investment Pact, governments are expected to provide long-term deployment visibility and measures to reduce investment risk, while the industry has committed to reducing offshore wind costs by 30% by 2040, creating 91,000 jobs, and investing in supply chains. This means offshore wind is moving from being primarily an “environmental policy” issue to becoming a central part of both industrial policy and security policy.

2. The Trend Is Moving Toward “Hybrid Offshore Projects”

A key concept for the future of European offshore wind is the hybrid offshore project. This means offshore wind farms are not connected to just one country, but instead linked to multiple national grids, enabling both power generation and cross-border electricity exchange at the same time. Countries such as the UK, Germany, Belgium, Denmark, and the Netherlands are examining frameworks for joint planning, cost sharing, and revenue allocation for such cross-border projects.

This marks a shift from the traditional business of “building wind farms” to a model in which power generation, transmission, and supply-demand balancing are designed together. For example, grid operators in the UK and Germany are also exploring new interconnector concepts that would link offshore wind farms in the North Sea to both countries’ electricity grids. In these types of projects, not only wind turbines but also high-voltage direct current (HVDC) submarine cables, offshore substations, grid control systems, and maintenance frameworks become critically important.

Therefore, the next bottleneck for European offshore wind is not necessarily the wind turbines themselves. Rather, the greatest focus is shifting to transmission infrastructure—where the generated electricity is sent, how it is transmitted, and how efficiently it can be delivered.

3. Grid Reinforcement Has Become Urgent in the UK

The UK is one of Europe’s leading countries in offshore wind deployment, but this also means that strengthening the power grid has become a major challenge. National Grid is advancing multiple large-scale transmission projects to deliver electricity from new renewable power sources, including offshore wind, to demand centers. For example, Norwich to Tilbury is a planned 400kV transmission line of around 180km linking Norfolk, Bramford, and Tilbury. It is an important project designed to carry new electricity generation from eastern England to demand centers in the south.

However, building this kind of grid infrastructure is not easy. The Times reported on National Grid’s 114-mile-class power line project, which is needed to transmit electricity from offshore wind but has also faced local opposition over pylons and landscape impacts. This is a common challenge across Europe. While power grids must be reinforced for decarbonization, onshore routes often raise issues related to landscape, land use, and local consent. For this reason, the importance of “less visible” transmission infrastructure—such as submarine cables and HVDC systems—is likely to increase further.

4. Submarine Cable Projects Also Carry Risks

Europe’s submarine power grid vision has great potential, but it also carries risks. In September 2025, Reuters reported that European prosecutors were investigating the Great Sea Interconnector, a planned project in the Eastern Mediterranean. The project aims to connect Europe with Cyprus and eventually Israel, but it has faced issues related to delays, cost, feasibility, and geopolitical concerns.

This case shows that submarine cable projects are not merely technical projects. Ultra-long-distance power infrastructure involves massive investment, regulatory coordination across multiple countries, maritime use, permitting, geopolitical risks, and cost allocation. Even in a region like the North Sea, where cooperation is relatively advanced, institutional design is essential: who pays, how revenues are shared, and who bears which risks.

In this sense, the construction of Europe’s offshore wind power grid is not simply a competition in generation technology, but an integrated contest involving infrastructure, finance, policy, and supply chains.

Sumitomo Electric’s Presence in Europe: Cables Become a Core Pillar of Europe’s Energy Transition

1. Sumitomo Electric Is at the Center of the Submarine Cable Era

Amid these European trends, one Japanese company that deserves particular attention is Sumitomo Electric Industries. Sumitomo Electric has built a strong track record in high-voltage direct current (HVDC) cables—especially XLPE-insulated cables—which are essential for offshore wind and international interconnectors. In 2019, it supplied and completed 400kV DC XLPE submarine cables for the NEMO Link between the UK and Belgium, and later expanded its orders through projects such as Germany’s Corridor A-Nord and the Greenlink interconnector between the UK and Ireland.

Sumitomo Electric’s strength lies not simply in its ability to manufacture cables. It lies in its world-class technological demonstration capabilities in HVDC XLPE cables, which are suited for long-distance, high-capacity power transmission. In 2022, the company announced that its 525kV DC XLPE submarine cable had passed a long-term demonstration test. According to the company, the test certified that stable long-term transmission of more than 2GW was possible—over 40% higher than the conventional maximum transmission capacity of 1.4GW.

In a 100GW-scale offshore wind network envisioned in the North Sea, large-capacity HVDC cables connecting wind farms to national grids will be indispensable. In other words, Sumitomo Electric’s technological domain sits at the very core of Europe’s energy transition.

2. The New Nigg Plant in Scotland Marks a Turning Point in Sumitomo Electric’s European Strategy

In April 2023, Sumitomo Electric announced the establishment of a power cable manufacturing and sales company in the Scottish Highlands in the UK. The background is the rapid growth of offshore wind in the UK and Scotland, making Europe one of the world’s largest demand centers for power cables. The company stated that by manufacturing power cables locally for the UK-centered European market, it aims to strengthen stable supply, long-term maintenance capability, and its overall presence in Europe.

According to the Consulate-General of Japan in Edinburgh, the submarine cable plant project at Nigg Port in Scotland involves an investment of approximately £350 million, with the construction of a 58,000 m² factory on a 15-hectare site. The plant is also expected to manufacture 525kV DC submarine cables, the world’s highest voltage class, and create around 330 jobs over the next decade.

The significance of this investment is substantial. In Europe, the expansion of offshore wind and international interconnectors has made submarine cable supply capacity a bottleneck. Sumitomo Electric’s decision to establish a manufacturing base in the UK is not merely the construction of an overseas factory. It means that a Japanese company is being incorporated into Europe’s clean energy supply chain.

3. Osaka Works as the Mother Factory, Nigg as the Local European Supply Base

In September 2025, His Royal Highness The Duke of Edinburgh visited Sumitomo Electric’s Osaka Works. Sumitomo Electric positions the power cable factory at Osaka Works as the “mother factory” for the new Scottish plant. During the visit, the Duke toured the power cable manufacturing process and pre-shipment testing, and also met engineers from Scotland who were undergoing long-term training in Japan.

This shows that Sumitomo Electric’s European strategy is not simply local production. It is a model for transferring quality control, manufacturing technology, and human resource development cultivated in Japan to Europe. In the construction of North Sea offshore wind grids, cable quality and reliability are extremely important. Once submarine cables are laid, failures are costly and time-consuming to repair and can have major impacts on electricity supply. This is why companies like Sumitomo Electric, with long-term demonstration records and experience in high-voltage cables, are becoming increasingly important.

4. The Sea Link Order: A Landmark Project Defining Sumitomo Electric’s Presence

The most recent project symbolizing Sumitomo Electric’s presence in Europe is Sea Link for the UK’s National Grid. In December 2025, Sumitomo Electric announced that it had received an order from National Grid Electricity Transmission for the Sea Link project, a 140km, 525kV HVDC XLPE cable project connecting Kent in southeast England with Suffolk in the east. The company entered into an EPC contract covering engineering, procurement, and construction. Construction is scheduled to begin in the second half of 2027 after development consent is obtained.

Sea Link is one of the core projects in National Grid’s “The Great Grid Upgrade.” It is important infrastructure for strengthening the UK’s existing transmission network and efficiently supplying renewable energy. The HVDC cables supplied by Sumitomo Electric are expected to be manufactured at the new plant under construction at Nigg Port in Scotland, contributing to local supply chain development, job creation, and decarbonization—priorities emphasized by the UK government.

What makes this project especially important is that Sumitomo Electric is not positioned merely as a materials supplier. Through the EPC contract, it is involved as a player responsible for engineering, procurement, and construction. Project partners include Siemens Energy and Van Oord, placing Sumitomo Electric alongside major European infrastructure companies in strengthening the UK power grid.

5. Track Record in International Interconnectors: Shetland2 and Greenlink

Sumitomo Electric has experience not only with Sea Link but also with Greenlink, the interconnector between the UK and Ireland. In 2021, a consortium formed by Sumitomo Electric and Siemens Energy won an EPC contract from Greenlink Interconnector Limited for a ±320kV DC transmission system connecting the UK and Ireland.

In addition, according to information from the Consulate-General of Japan in Edinburgh, at the groundbreaking ceremony for the Nigg plant in Scotland, it was announced that Sumitomo Electric had been selected as the preferred bidder for Shetland2, a 525kV HVDC XLPE cable project of around 330km planned by SSEN Transmission to connect mainland Britain and the Shetland Islands. This is considered important infrastructure for transmitting offshore wind power around Scotland to mainland Britain.

Looking at these projects together, Sumitomo Electric’s European strategy is clear. It aims to increase its presence as a core cable manufacturer responsible for both international interconnectors and offshore wind connections across the UK, Ireland, and Scotland.

6. Challenges: Demand Is Strong, but Factory Ramp-Up and Supply Responsibility Are Heavy

At the same time, Sumitomo Electric’s new UK plant also faces challenges. In November 2025, The Japan Metal Daily reported that construction of the factory building for the company’s power cable plant in the UK had been delayed by around five months. As a result, the start of production, originally scheduled for the second half of 2026, is now expected to be delayed, possibly starting from fiscal 2027 at the earliest. However, the report also stated that there is not expected to be an impact on the construction schedules of already awarded projects.

This shows that while growth in Europe’s offshore wind and transmission grid market is significant, building and ramping up a cable factory itself is not simple. High-voltage submarine cable production is a complex business involving manufacturing equipment, quality assurance, testing facilities, skilled workers, and coordination with cable-laying vessels. Precisely because demand is expanding in Europe, the responsibility to supply reliably is becoming heavier.

For Sumitomo Electric, whether it can bring the Nigg plant online as a fully capable production base will be a critical factor determining its future presence in Europe.

Conclusion: Europe’s Offshore Wind Grid Opens the Era of Cable Companies

Europe’s offshore wind sector is moving from an era of simply building wind turbines to an era of constructing cross-border transmission grids. Looking at the North Sea 100GW vision, cross-border projects planned for the 2030s, the UK’s Great Grid Upgrade, and long-distance projects such as the Eastern Mediterranean interconnector, the focus is shifting from how much power can be generated to how efficiently, reliably, and across borders electricity can be transmitted.

Within this transition, Sumitomo Electric has taken an extremely important position as a Japanese company. Its involvement in NEMO Link, Greenlink, 525kV XLPE technology, the new Nigg plant in Scotland, the Sea Link order, and the Shetland2 project shows that the company is deeply embedded in Europe’s renewable energy transmission infrastructure.

The construction of Europe’s offshore wind power grid will continue to face challenges related to policy, financing, local consent, and supply chains. However, in one of the key bottleneck areas—high-quality, large-capacity submarine cables—Sumitomo Electric is already establishing a strong presence in Europe.

For Japanese companies, this is highly instructive. In Europe’s green transformation market, major opportunities exist not only in finished products or power generation equipment, but also in materials, cables, power equipment, construction, and maintenance that support infrastructure. Sumitomo Electric’s case is a strong example of how Japanese companies can become deeply involved in Europe’s decarbonization infrastructure.