Smart solutions can help save billions on energy islands

Thursday 28 Oct 21


Jacob Østergaard
Professor, Head of Division
DTU Wind
+45 45 25 35 01


Nicolaos A. Cutululis
DTU Wind
+45 21 32 49 65
The challenges and opportunities outlined in the white paper ‘Energy Islands—A ‘Mars mission’ for the Danish energy system’ will be discussed at seminars in the autumn with the participation of researchers, companies, and authorities. Read more about the seminars.
The contribution is published in Altinget October 27 2021
Contribution in the media 'Altinget': With new innovative solutions, we can save at least DKK 20 billion once Denmark’s two energy islands are fully operational. 

By: Jacob Østergaard, Professor, DTU Electrical Engineering, Professor Nicolaos Antonio Cutululis, DTU Wind Energy, Professor Frede Blaabjerg, Aalborg University

Denmark holds a leading position when it comes to utilising and developing renewable energy. With the decision to establish the world's first energy islands, we can be in poll position for many years to come. However, it requires us to think smart from the start.

The construction of energy islands is a task like no other before it. Fortunately, we have some experience to draw from. At DTU and AAU, we have been working with technologies on energy islands for the past ten years, and have just recently published the white paper” The Energy Islands—A ‘Mars mission’ for the Danish energy system".

Against this background, we will point to three examples where we cannot just copy our existing solutions when the islands are to be built, without it becoming unnecessarily expensive for society. Through more closely targeted research, we should already be ensuring large savings as well as future-proofing the energy islands, so that we do not end up in a dead-end without the possibility of adapting the islands to the challenges that arise in 10 or 20 years. The three examples are: changing the requirements for wind turbines, designing the transformer station on the energy islands in a new way and developing the wind turbines to produce hydrogen.

1. Changed requirements for the wind turbines

The components of our current wind turbines are subject to strict requirements. This is necessary, as they are all directly connected to the electricity grid, which is sensitive to potential errors in the turbines and their operation.

The wind turbines on the future energy islands, on the other hand, will not be connected directly to our national electricity grid. Instead, they are connected to a transformer station on the energy island before the electricity is sent on to the mainland via controllable direct current cables. This enables us to change the requirements for the wind turbines connected to the energy islands. With a focused research and development effort, we can develop wind turbines with electrical components that are optimized for these requirements. This could lead to a saving of around DKK 7.5 billion without affecting the operational reliability of the electricity system.

2. New transformer stations design

The energy islands are built with a transformer station that converts wind turbine energy before sending it via cables to the mainland. Here, it first encounters a new transformer station that ensures adaptation of the electricity to the conditions in the electricity grid before distributing it in the grid. This can be simplified, as the transformer stations of the wind farms that are connected to the energy island could potentially be eliminated. It could reduce costs by DKK 12 billion, however, it would require a research effort to verify that the solution does not affect the operational reliability of the energy sources.

3 Hydrogen production on the islands cuts transportation costs in half

On the energy islands, we can convert part of the power into hydrogen, which is much cheaper to transport. For example, we can do this by building power-to-x systems in the turbines, so that the wind turbine can convert the energy into hydrogen when there is no need for electricity. This requires research and development of new turbines. In return, the hydrogen can be transported in the pipes that are already being established for the power cables running between the energy islands and the mainland – and at half the cost. Our calculations also show that if we develop offshore power-to-x technology, it will be 12% cheaper to produce hydrogen on an energy island and transport it to the mainland than to have the entire hydrogen production take place on land.

Total savings of at least DKK 20 billion

The three research efforts mentioned provide a saving of at least DKK 20 billion. In our opinion, this is such a large amount that it would be irresponsible not to seize the opportunity to develop new innovative initiatives, when we begin establishing the two energy islands. The three examples mentioned here are based on results from our preliminary research efforts, but other possibilities for new development should, of course, also be explored.

At this moment in time, we have a rare opportunity to think in terms of new unique solutions that can both help strengthen our position as a leader in green energy and mark the beginning of an export adventure when future energy islands needs to be designed all around the world. We have to seize that opportunity.