Building the Future Offshore: How Energy Islands Could Transform Global Energy

Building the Future Offshore: How Energy Islands Could Transform Global Energy

It is widely recognised that the current sourcing of global energy is unsustainable, with roughly 70% of total worldwide energy still coming from non-renewable sources, and climate change fast approaching, the global energy scene must evolve. While we are taking steps in the right direction, greater scale and commitment are needed now more than ever. Our future energy will not come from fossil fuels, nor will all of it come from renewable farms on the land we already inhabit; we have not the space or willingness to fill our communities with large, unsightly renewable plants. We must think bigger. Think colossal artificial landmasses, covered with solar panels and surrounded by offshore wind turbines — land built with the sole purpose of powering our planet without destroying it. Located away from communities, net-zero over their lifetime, and so large they could power whole countries, or even continents, these structures are known as energy islands. However, this is not just a concept; projects like this have already been planned and funded. While current projects are not large enough to meet worldwide energy demand alone, they will help certain countries reach their climate goals, and, hopefully, the success of these upcoming energy islands will encourage larger-scale projects to be developed in the future.

Take the Danish energy islands, for example — two islands that are already planned, already funded, and almost ready for construction. These islands will generate sufficient energy to power millions of homes across Denmark, Germany, and the Netherlands, advancing these countries toward their climate goals. The first project, named the Bornholm Energy Island (BEI), was founded through the collaboration of two national electricity operators: Energinet and 50Hertz. The project was first proposed and accepted by the Danish government in 2021, and as of 2026, the project is fully funded, with major supplier contracts signed and sealed. This means that the construction of BEI could begin as early as 2027. Fundamentally, BEI will connect several wind farms via a single hub and transport the green energy generated to consumers in multiple countries. The system will also provide transmission capacity for cross-border trading. Electricity generated by the wind farms surrounding the island will be centralised at the hub, then converted into high-voltage direct current (HVDC) and transmitted via HVDC land and sea cables to substations located in Zealand (Denmark) and Mecklenburg-Western Pomerania (Germany). Ultimately, the project aims to connect countries and pave the way for a future in which renewable energy is not harvested by individual countries alone but instead traded internationally to help power the green transition for all.

The second planned project is called the North Sea Energy Island (NSEI). Unlike BEI, NSEI will be the world’s first artificial energy island. This island was also proposed in 2021 and now has a three-gigawatt (GW) completion target of 2036, with a planned expansion to 10 GW by 2040. NSEI is situated 100 kilometres off the coast of Denmark and will be surrounded by ten offshore wind farms, using the strong North Sea winds to harvest large quantities of green energy for Denmark and Europe. NSEI aims to play a key role in helping Europe phase out its dependence on fossil fuels, as the 10 GW expansion will generate enough energy to power approximately ten million households.

The North Sea itself will be central to the green transition. With its shallow sea depths and exceptional wind conditions, it has the potential to host over 200 offshore wind farms, each with a capacity of 1 GW. This would provide almost enough power to meet all of Europe’s household energy consumption. The scalability of energy islands clearly places them at the forefront of future energy supply. However, as with all large infrastructure buildouts, there are several limiting factors to the creation of larger and more advanced energy islands.

First, there is the immediate monetary cost. NSEI alone has an estimated cost of 24.5 billion GBP, with only 5% of this covering the cost of the actual island and the remaining 95% allocated to the construction of wind farms and cable links. To fully utilise the North Sea with energy islands would cost approximately twenty times this amount, meaning projects must be future-proofed before such enormous investments are made. Second, the construction of artificial islands presents environmental challenges, particularly the disruption of marine life, as habitats and migration paths may be affected. However, solutions are being developed. Firms constructing the Princess Elisabeth Energy Island in Belgium have implemented a ‘nature-inclusive design’, incorporating ledges for cliff-nesting birds, and underwater panels to encourage the attachment of marine life. While not perfect, measures such as these to reduce the harm caused by artificial islands may help accelerate future construction. The public instead more confident that the benefits outweigh the drawbacks.

With global energy demand continuing to rise and climate change accelerating, immediate action is required. Energy islands represent a bold, but arguably essential, step in the energy transition to mitigate these challenges. While they are far from meeting worldwide energy demand alone, current projects demonstrate that the concept is no longer theoretical, but instead logistically and politically achievable. If economic and environmental costs are managed effectively, energy islands offer a truly scalable solution to the most pressing problem the world has ever faced.

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