Dynamic cables – opening up new markets in offshore wind development

Did you know that 80% of the total ocean space is too deep for conventional offshore wind farms?

As wind energy takes on a greater role in providing sustainable electricity to millions, harnessing stronger and more consistent winds found farther offshore is critical. In recent years, advancements in high-voltage (HV) dynamic cables, critical to transporting energy back to land, are opening up new opportunities for offshore commercial wind power.

Harnessing wind power in areas previously impossible

A vast, untapped potential lies in harnessing offshore wind power. Although fixed-bottom wind projects currently lead offshore generation, nearly 80% of the world’s offshore wind potential is in waters deeper than 60 meters. This offers a tremendous challenge for the electrical transmission industry.

Yet, during the past thirty years, offshore wind has played an essential role in the decarbonization of energy. According to McKinsey, the growth of offshore wind capacity is projected to reach 630 gigawatts (GW) by 2050, up from 40 GW in 2020.

Since deeper waters are common along most coastlines worldwide, floating offshore wind turbines are crucial for these regions to harness offshore wind energy. Thus, floating offshore wind offers many countries and regions a viable path to electricity decarbonization. But getting this energy back to shore requires robust HV dynamic cables that can withstand the harsh conditions of the seas.

From sea to shore: How tech breakthroughs are powering up floating wind farms

One of the many advantages of placing wind turbines further out from the shoreline is the sheer power of the winds. More powerful and consistent wind speeds equate to a more reliable energy source.

Turning this powerful wind into sustainable energy is possible in part due to new developments in HV dynamic cables and enhancements in floating wind turbines and substation designs.

And it is thanks to these advances that by the end of the decade, large-scale floating wind farms on the West Coast of the United States, France, and South Korea will finally be a reality.

And we’re already seeing this happen. The first commercial floating wind project to be awarded is in France, off the coast of Southern Brittany. This monumental project will, upon completion, be the largest floating offshore wind farm in the world. The 250 MW site will double Europe’s current floating offshore wind capacity.

However, reaching this milestone requires getting the energy back to land where it can be transmitted and used. And this is where HV dynamic export cables are the critical link. To do that requires cables that can withstand deep-water seas. A feat that has taken years to achieve!

4 differences: Breaking new boundaries in HV dynamic cable design

1. Dynamic vs. static HV subsea cables

2. Water resistance of dynamic cables

3. Design simulation to achieve greater mechanical performances

4. Collaboration between stakeholders is critical to project success

Overcoming new challenges going forward

The oil & gas industry has a long history of using medium voltage (MV) electrical subsea equipment. Today, that same philosophy is being explored for subsea substations. However, HV systems are a different playing field!

Transitioning to HV subsea equipment brings in a lot of additional challenges due to both increased voltage and larger sizes. This generates new challenges for design and handling offshore, combined with even more strict requirements for design tolerances and water tightness.

All HV subsea systems, including cables and potential substations and their connectors, require significant testing and qualification efforts over long time spans. Often, new failure modes arise as we acquire more knowledge about higher-voltage subsea equipment.

When it is possible to install subsea offshore substations or converter stations on the seabed, it will be a game-changer. It will unlock vast new areas for wind energy production, improve efficiency, and contribute significantly to the transition towards a sustainable energy future. For example, this advancement will significantly enhance the cost efficiency of electrical export, ultimately reducing costs and optimizing resources.

Driving the critical link in floating wind power

The largely untapped deep-water areas open up new opportunities for floating wind farms. A key link to the future of floating wind is the vital cables required to transport energy to shore. Nexans is driving innovative cable technologies and design methodologies to further the development of commercial floating wind farms.

A long track record in dynamic hybrid cables is led by the Group’s experience in materials, modeling, and software development. Dynamic power umbilicals & DEH systems experience, combined with its HV subsea cable expertise, this gives a unique combination of design and manufacturing know-how, allowing to simulate, test, qualify, and manufacture HV dynamic cables.

In 2021, Nexans made a major breakthrough by qualifying the first 145 kV dynamic cable for 1300-meter water depth. Selected for the Jansz-lo project, this innovative cable is leading the way for floating offshore wind projects.

Growth of floating wind farms in the years to come

The vast open seas hold great potential in the world’s quest to decarbonize electricity. Floating wind farms, farther out and deeper, will play an increasingly important role in the battle against climate change.

Major advancements in HV dynamic capabilities play a critical role in achieving the commercial success of floating wind farms. Nexans’ groundbreaking 145 kV dynamic cable capable at 1300 meters opens up new opportunities for deep sea projects in harsh water conditions. This innovation is crucial for the future of commercial floating wind farms.

According to an August 2023 Global Wind Energy Council (GWEC) report, the floating wind market will accelerate by the end of the 2020s, with 11 gigawatts (GW) installed by 2030 and 26 GW by 2032.

Starting in 2031, floating wind installations will constitute over 10% of annual offshore wind installations, a notable achievement given the rapid expansion of offshore wind overall.

This growth will significantly contribute to adding decarbonized electricity generation to power grids, supporting global efforts to reduce carbon emissions, and the transition to sustainable energy sources.