After president's Biden announcement on its ambitious goal of cutting US greenhouse gas emissions by at least 50% by 2050, compared to 2005 levels we addressed the importance of offshore wind power towards the accomplishment of this goal. You can find more about this on our previous Article: The Promising Future of Offshore Wind Power.

Even though the offshore wind industry has grown dramatically over the last several decades, and that the USA's first commercial scale offshore wind farm (the 800 MW Vineyard Wind project) has been approved this year and to be delivered in 2023, this is just a drop in the bucket of what's needed (30 GW).

The world needs to be installing an average of 180 GW of new wind energy every year to limit global warming to well below 2°C above pre-industrial levels, and will need to install up to 280 GW annually from 2030 onwards to maintain a pathway compliant with meeting net zero by 2050 - according to the Global Wind Energy Council 2021.

Eventhough costs for offshore wind power are declining, mostly due to the evolution of the turbines - offshore wind is not yet a competitive market, prices still have to go down in most markets, especially to those markets where there are no carbon taxes or these are not high enough. In the US, at the moment there are no leasing processes to build large scale offshore wind projects and permitting processes still remain complicated. So how and when can this necessary transition to offshore power be done?

Hybrid: Oil & Wind

The answer today is relying on hybrid solutions. Companies like Odfjell Oceanwind are developing floating mobile drilling and offshore wind units. The company has 15 years of experience working in the oil and gas industry as a drilling company with their Mobile Offshore Drilling Unit (MODU). But today they are also developing their Mobile Offshore Wind Unit (MOWU), the MOWU is purposed to help meet the 2030 targets in those markets where offshore wind is still not economically viable. It works as a mobile wind turbine on a floating station to supply electricity for the drilling of oil offshore

This may not be the ideal or greener solution but will help transition to offshore wind and decarbonize the grid in the short-term. It is still somehow controvertial to prioritize power supply to oil and gas installations. The MOWU can be used for temporary needs, wouldn't require any license and would be able to be moved from one drilling station to the next as needed. This hybrid solution with the MOWU can allow up to a 70% of CO2 reductions as stated by Odfjell Oceanwind (and verified by DNV GL) in comparison to keep powering the drilling stations with gas turbines, this would translate to near 40,000 ton of Co2 per year per each MOWU. So while transitioning to offshore wind, this solution should not be overlooked..

Offshore Wind Optimization

Other ideas that hope to bring costs down for offshore wind power installations are brought by companies like:

• Floating Power Plant - they sell floating foundations for offshore wind power but integrating the wind turbine (4 MW to 15 MW) with wave power generation (1MW to 4MW). The platform is moored at a single point allowing the platform to passively rotate to face the waves. By doing this they achieve higher power density and lower LCOE. Today, they have one project in the water, in Denmark being the first platform in the world that generated wind and wave power at the same time and are already planning new projects around the globe.

• RCAM Technologies - offers solutions to accelerate ET using 3D concrete printing. Among these solutions they are developing wind towers designs that can be 3D concrete printed on-site to overcome transportation constraints and reduce material usage and carbon footprint. They also offer concrete anchors for offshore wind power and even a Marine Pumped HydroElectric Storage (M-PHES) solution for long-duration storage for offshore wind projects

• Hexicon - their solution is Foundations only. Based on incline towers and standard components. Copied from oil and gas industry. One foundation and one mounting system for two turbines instead of one. Doing this they will then reduce most O&M, cabling, and costs by half or less. Wind Towers are side by side and power density would be increased.

Hybrid: Wind & Hydrogen

Compared to the transport of electricity generated offshore, the hydrogen production at sea and the transport via pipeline could offer clear economic advantages for transporting large volumes of energy over long distances. The pipeline could replace five High Voltage Direct Current (HVDC) transmission systems, which would otherwise have to be built and have a large impact on the LCOE of offshore wind projects.

In this sense, the AquaVentus project is being planned in Europe, to contribute towards the de-carbonization of energy supply and brining down costs. Companies like RWE, Shell, GASCADE, and Gasunie who have been part of AquaVentus from the start and others like Ørsted, Equinor, WindMW, the Japanese utility J-Power, Hitachi ABB Power, McDermott (US offshore engineering and construction firm) and Van Oord Offshore Wind Germany, who have been joining the project along over the past months, all have committed to collaborate in this project.

The AquaVentus initiative, which is behind a massive project revolving around green hydrogen production powered by 10 GW of offshore wind from the North Sea, comprises numerous sub-projects along the value chain from the production of hydrogen in the North Sea to transport to customers on the mainland. The projects include the development of:

• offshore wind farms with integrated hydrogen generation (AquaPrimus),
• a large-scale offshore hydrogen park (AquaSector),
• a central supply pipeline (AquaDuctus),
• port infrastructures (AquaPortus),
• a research platform (AquaCampus),
• and hydrogen-based maritime applications (AquaNavis).

Under the first sub-project, AquaPrimus, the consortium plans to install two 14 MW wind turbines, each with an electrolyser plant on its foundation platform. The wind turbines would be installed off the coast of Heligoland by 2025. The AquaSector project will be the first large-scale offshore hydrogen park. The project intends to install approx. 300 megawatt (MW) electrolyser capacity to produce up to 20,000 tons per year of green hydrogen offshore. The green hydrogen is planned to be transported via a pipeline, the AquaDuctus, to Heligoland starting in the year of 2028.

While the offshore wind industry has grown dramatically over the last several decades, it still has a long way to go and innovation is in place to achieve grid de-carbonization. Whether it is with short-term solutions like Odfjell's MOWU or for the long-term under the AqueVentus project. Would you be interested in Darcy evaluating this market and find solutions for construction and/or O&M solutions for offshore wind farms?

Would you be interested in an offshore wind Forum or being involved in a small scale (max. 10 people, no spectators) Roundtable discussions with your peers on this topic? Let us know your thoughts below!

References and further reading

• Joyce Lee, Feng Zhao. (2021). Global Wind Report 2021. Global Wind Energy Council. Link.
• Buljan, Adrijana. (June 21, 2021). McDermott, Van Oord Join AquaVentus Offshore Wind-to-Hydrogen Project. OffshoreWIND.biz. Link.
• Article image courtesy of Zachary Theodore. Published on January 6, 2020. Unsplash. Link.