Energy islands can make Denmark a world leader

Europe from space

It will be an engineering feat to build the world’s first energy islands, and can give Denmark great export opportunities.

Tekst: Christina Tækker og Lotte Krull

It is not a trivial task to design and construct two energy islands. It has never been done before. The project requires research, development, and innovation on such a large scale that it can be compared to planning a mission to Mars.

Everything about the two islands is large-scale. The total capacity is expected to be 12-13 GW of offshore wind by 2040, corresponding to the power consumption of 12-13 million households. The construction cost of the artificial island in the North Sea is also very high. The Danish Ministry of Climate, Energy and Utilities estimates this to be DKK 210 billion.

However, the first energy island on the drawing board is Bornholm, which will have two linked offshore wind farms. It will be possible to test the energy island technologies on Bornholm and later transfer them to the energy island in the North Sea, and to anywhere else in the world where there is massive expansion in offshore wind farms.

Professor Jacob Østergaard from DTU has been researching smart energy solutions for many years and heads several projects based on Bornholm, including the experimental PowerLabDK platform. PowerLab is a living laboratory for energy production and consumption and is connected to Bornholm’s energy system.

It allows researchers to monitor, control, and collect data from the production and consumption of wind power etc., and thereby gain insight into how to develop smart energy solutions.

“Bornholm is interesting as an energy island, because we can quickly get started. We have an established platform and can test various constellations and management methods in a flexible environment that already functions as a living energy laboratory,” says Jacob Østergaard.

New solutions required

The aim is for the Bornholm and North Sea energy islands to supply wind power for electric cars, heat pumps, households, and companies, and to export power to our neighbouring countries. Longer term, batteries and Power-to-X technologies will be coupled to the energy islands.

This will make it possible to store and convert the power into hydrogen and other fuels that can be used in aircraft, ships, trucks, etc.

However, this requires the development of new technological solutions to ensure the energy islands have a solid structure and supply stable power. The solutions must be designed to allow future expansion and the connection of more islands.

“We could take all the technologies we have today and put them together like building blocks. But we risk making a system that will be too expensive and perhaps not reliable,” says Jacob Østergaard.

In the PowerLabDK living energy laboratory, DTU researchers can monitor Bornholm’s green power consumption and use data to test and develop smart energy solutions. (Photo: Torben Nielsen)

The plans to expand power generation with offshore wind are ambitious. In Europe alone, the EU has decided to expand capacity by up to 300 gigawatts by 2050. By comparison, the EU’s total capacity today is only 12 gigawatts, according to the European Commission.

The ambitious target for offshore wind power is opening up a new potential for the green transition and the Danish wind turbine industry.

“The two energy islands in Denmark will give Danish consultancy and construction companies first-hand experience with the construction of artificial islands and implementation of the associated technology,” says Troels Stybe Sørensen, Senior Director at Ørsted, which develops offshore wind farms as one of its activities. He sees great global development and export potential in the energy islands:

“The situation is reminiscent of the start of large-scale offshore wind in Denmark in around 2002, when Nysted and Horns Rev 1 were built at two different locations using different technologies—monopiles and gravitational foundations, respectively, and using different turbines. This gave the Danish offshore wind industry a unique competence.”

When the two energy islands are established (planned in 2033), Denmark will take a big step towards the green transition. In the longer term, Jacob Østergaard envisions a network of islands connected to each other—and to several countries, making an entirely offshore energy grid.

“If we succeed, it will make Denmark the absolute leader in relation to using and developing renewable energy for many years to come, and can potentially become a new Danish green energy success story,” says Jacob Østergaard.

Energy Island North Sea
The illustration shows some of the functions that a 3 GW artificial energy island in the North Sea might be able to accommodate. Note that the island’s size, appearance, and precise functions have not yet been decided. (Kilde: The Danish Energy Agency)
• By 2033, there will be an energy island in the North Sea, about 80 km from Thorsminde on the west coast of Jutland.

• The island will gather 3 GW from offshore wind turbines further out to sea. Around 2040, the island will collect 10 GW of offshore wind.

• The power will be passed on from the island via connections to Denmark and to one or more other countries.

• The budget is DKK 210 billion, with around 5 per cent for the establishment of the island, 35 per cent for the electrical infrastructure, such as HVDC connections etc., and 60 per cent for offshore wind farms.


Jacob Østergaard

Jacob Østergaard Professor, Head of Division Department of Wind and Energy Systems Phone: +45 45253501 Mobile: +45 25130501