There is limited space on the seabed of the North Sea. At some point, we will run out of suitable locations for offshore wind turbines, and it will become too expensive to establish them in other waters.

So what do we do then?

The answer could be floating offshore wind turbines.

“We need to look to the future and research solutions now, so that we can be ahead of the reality that will confront us,” says Lau Fogh.

He is a PhD student at the Department of Civil and Architectural Engineering, investigating new ways to anchor floating offshore wind turbines.

Today, large wind turbines are placed on the seabed in the North Sea, the Yellow Sea off China, and off the U.S. East Coast, among other locations.

Here, the conditions are favorable, and the water is shallow enough. But as more offshore wind farms are built, space is becoming increasingly constrained.

The alternative might then be the floating type.

“If we want to reach the EU’s offshore wind targets, we need new technologies that can overcome these limitations in the long term,” says Lau Fogh.

Lack of space is not the only challenge.

Other major oceans do not offer conditions suitable for fixed-bottom offshore wind turbines. Australia, large parts of South America, and the U.S. West Coast are examples of regions where the sea becomes very deep quickly, making it unrealistic to install fixed-bottom offshore wind turbines with current technology.

“Even though there is no immediate problem today, we are working on a solution that will be ready in 20 or 30 years. Because we will need an alternative if we are serious about wind energy,” emphasizes Lau Fogh.

In the floating version, the structure is anchored with mooring lines and several anchors in the seabed, keeping the turbine stable instead of hammering a pile deep into the ground.

Currently too expensive

Today, there are around 10 pilot and demonstration projects for floating offshore wind turbines in Europe. So the technology already exists.

But the biggest obstacle to widespread deployment is cost, according to Lau Fogh.

“Right now, it costs three times as much per installed megawatt to build floating offshore wind as fixed-bottom farms,” he says.

Currently, this can mean construction costs in the range of 6–8 billion euros for a large offshore wind farm. The goal is to bring costs down to around half by 2050.

“This can only happen if we, researchers and industry developers, tackle the task and reduce costs on the technical side,” he says.

This is precisely what Lau Fogh’s research focuses on: optimizing and finding solutions that can make the technology cheaper and more sustainable.

“Because if we cannot reduce costs, it is not a viable solution,” he says.

A floating offshore wind turbine is typically held in place by three to six anchors. The anchors must be both cheaper than current designs and strong enough to withstand the enormous forces from wind, waves, and currents acting on a structure weighing several thousand tons.

New design can solve the problem

Lau Fogh is therefore researching a new design for anchors for floating offshore wind turbines.

Current designs require large amounts of steel, and ultimately the goal is to use as little steel as possible—without compromising safety requirements.

His preliminary results indicate that it is possible to develop more efficient solutions.

Research shows, for example, that simply increasing the steel mass in one type of anchor in hopes of using fewer anchors does not yield significant benefits.

Instead, Lau Fogh has found that greater efficiency can be achieved by combining two different anchor types in a new design.

“You take a pile that serves one function and place a plate on top that serves another function. Together, you get a new anchor that is far more effective than just increasing the number of anchors.”

In this way, the amount of steel can be reduced by approximately 20–40 percent.

Physical testing in the U.S.

Lau Fogh is currently in Davis, California, USA, conducting a series of advanced tests with his newly designed anchor.

Prior to this, he used computer simulations to test the anchor’s performance, which showed promising results.

“One test method can indicate potential, but with two different test methods, we come as close as possible to reliable evidence,” explains Lau Fogh.

The University of California, Davis is renowned for its research environment in geotechnical engineering and offshore studies, and therefore has physical test setups that can simulate real loads from waves, currents, and wind.

“This makes it possible to thoroughly test new ideas, assess their potential, and gain insight into how to improve future design methods,” he says.

According to Lau Fogh, it is important to research new designs and more sustainable methods if wind energy is to be a central part of the future energy supply.

“We improve the technology so that we can bring forward the best and cheapest solutions when political decisions push the button,” he says.

Other alternatives to floating offshore wind turbines could be solar energy or nuclear power.

“But solar energy cannot stand alone. Therefore, we need to think long term about wind energy. Opposition to onshore wind turbines is strong, so there is significant potential in placing them at sea,” says the young researcher.

By advancing offshore engineering, the research contributes to making floating offshore wind technically robust and economically viable in the future energy landscape.

“We are developing and driving innovation in a sector that could become extremely important if we are to continue reducing emissions,” says Lau Fogh.