Sustainable steel applications for offshore renewables –interesting innovations and development within floating offshore wind power and marine technologies

Eight very interesting speakers with different perspectives in the value chains of offshore renewables came to HTSC 2018 and shared their knowledge, experiences and examples of demanding challenges in harsh offshore renewable environments. One keynote from a big classification company, two speakers from two world leading steel manufacturers and five speakers from innovation and development companies. Examples and knowledge about using advanced steel applications were shown to achieve a more sustainable future and new business opportunities within a new emerging, global and sustainable market for offshore renewables. For example, offshore wind, ocean wave power, tidal power and ocean harvesting.

Johan Sandberg, Country manager Sweden from DNV GL held a very inspiring and exciting presentation, “Offshore renewables – the future of energy or just a ripple on the water?” He means that Offshore Renewables is a must win battle for the climate. Offshore renewables will become an increasing part of future energy and a big global market supported by increasing investments in floating offshore wind energy. Johan described a big step within the oil and gas industry which now will invest in floating wind farms for water injection (WIN WIN).

To encourage us to explore the possibilities of using high strength steel in dynamic loads Joakim Nyström from SSAB held a presentation about how it is possible to make use of high strength steel in dynamic load situations. When having a fatigue driven load case, you need to adapt the design to enable weight reducing benefits with high strength steel.
Different factors need to be considered depending on the load cases that are relevant.The challenge is often related to joints – summarized in three different actions to achieve longer fatigue life.For example:
- Remove welding in low stress position
- Replace top weld removed and from high stress area in flanges and replaced with bolts attached to the web and bracket in low stress areas.
- Refine by using fish tail joint or HFMI (high-frequency mechanical impact treatment).

Gabriel Strängberg from SeaTwirl gave delegates an engaging insight into “The future of offshore wind power and sustainable energy benefits from sustainable materials.” SeaTwirl has a quite unique solution for floating wind power with a vertical-axis wind turbine and is developing the future of wind power. What can SeaTwirl benefit from using sustainable materials?

Gabriel talked about the potential of choosing offshore wind power as the ocean is a very unused resource and that possible wind power energy production potential is much larger offshore than onshore. A 1 MW wind turbine is under development and is planned to be ready for test 2020. Sustainable steel could be a good solution for some parts of the structure to achieve sustainable energy solutions with SeaTwirl.

The first applications for SeaTwirl installations will probably be fish farms, islands and other remote locations.

Tomas Forsman from Sandvik Materials Technology continued with a presentation about Sandvik strip steel for marine applications.

Sandvik strip grades have found many applications where the high temperature, high mechanical loading or corrosive environment have set the target for the properties. With Sandvik SAF 3207 HD strip they are expecting to see marine applications where high yield strength, high fatigue resistance and high resistance towards crevice corrosion in chloride environments, is called for. For instance, the segment of renewable ocean energy should benefit from this grade.

The second day of the conference kicked off with a presentation by Urban Joelsson from Flowocean about "Steel - a key ingredient for a sustainable clean energy future."

Floating offshore wind and advanced steel solutions are at the heart of our future sustainable energy infrastructure. Flowocean’s solution for offshore wind power has
different key technologies features. By using a column and wire combined structure a soft and flexible solution is achieved and pylons and tubes can be designed for much less bending force, thus less fatigue and lower weight.

A full-size demonstration project will start this year and will be planned and commissioned 2020.

Fredrik von Heland from Offshore Access AB also held a very interesting and detailed presentation of their solutions for "Safe boarding of offshore structures."

Offshore Access AB is developing a system to allow a safe, fast and economical access to offshore structures. Transferring personnel and equipment from a service vessel to any structure at sea has always been a difficult operation. Oil rigs, accommodation platforms, wind turbine foundations and ships all have the same problems; personal injuries, damage to the transfer vessel or to the structure itself and the time factor. This has forced the industry to develop sophisticated methods at high costs, often vulnerable to single point failures. Offshore Access AB offer to the market is a straightforward robust system with low maintenance at a moderate cost. It will also allow for smaller workboats to be used, this put together is vital, especially for the offshore wind industry where margins are tight and good accessibility a must. Full scale demonstrations will take place in Oskarshamn, Sweden, during Q1 2019. For more information, please contact Fredrik: fredrik.vonheland@offshoreaccess.se

Niklas Hummel from Hexicon AB gave an interesting presentation about “Multiturbine efficiency in floating offshore wind power.” Hexicon design semi-submersible platforms for floating wind power. Their design with two turbines on one foundation utilizes a single point mooring system to passively aligns with the wind and increase energy yield.

Håkan Rosén from SSY concluded the session with an inspiring presentation, “The greatest environment innovation.” He covered how to use the properties in duplex steel, the invention of SSY, ships’ global pollution problems, creating the greatest environment impact, and finally LCC advantage using duplex steel and super light design.

Final thoughts

There were three different companies with three different solutions for floating offshore wind market. There will be hard competition for floating offshore wind power energy against other types of energy and crucial for success is what LCOE (levelized cost of energy) it will achieve. At the thematic session the different speakers agreed that there will be a very big market and demand for many different suppliers.

And we are convinced that smart usage of sustainable high-tech steel for offshore renewables will make it possible to achieve more reliable and effective solutions to achieve more competitive energy prices with sustainable technologies that are good for everyone, our environment and the future of our children.