Earthquake-resistant ‘flexible tripile’ offshore foundation for wind turbines unveiled

A Japanese company has designed an earthquake-resistant foundation for fixed-bottom offshore wind turbines. Developed by J-Power and the University of Tokyo, the ‘flexible tripile’ foundation is tailored for Japan’s topography.

The newly devised technology incorporates square steel pipes and steel plates in the foundation’s base plate, creating a flexible structure that can deform relatively easily, according to the company.

J-Power claims that the design provides seismic isolation from the ground, improving constructability in areas with shallow bedrock and reducing vibrations caused by earthquakes.

The long, integrated steel pipe section

The company also maintains that the simplified foundation components allow for lower construction costs than conventional technologies.

The company claimed that monopile foundations, which have a proven track record in Europe, are frequently used in bottomfixed offshore wind turbines, which are currently being introduced on a large scale. However, monopile foundations are unsuitable for areas with relatively hard bedrock close to the surface, as is often the case in the waters around Japan.

Drilling efficiently into such bedrock is challenging, necessitating the use of conventional technologies and resulting in higher construction costs.
J-Power maintains that the long, integrated steel pipe section allows the entire wind turbine to sway slowly (long-period motion), reducing the risk of tower oscillations being amplified due to resonance with seismic motion.

Seismic isolation effect minimizes earthquake-induced vibrations

“Additionally, the devised seismic isolation effect minimizes earthquake-induced vibrations. J-POWER’s calculations indicate that the simplification of foundation components, compared to conventional technologies, can be expected to result in significant cost reductions. This technology is also anticipated to be easily adaptable to larger wind turbines in the future,” said J-Power in a press release .

J-POWER stated that it conducted joint research with the University of Tokyo on this technology and their analysis has confirmed the technology’s effectiveness.

Model experiments have proven efficacy

The company claimed that model experiments have also demonstrated that this foundation structure reduces earthquake-induced vibrations more effectively than conventional designs.

The company stated that it will continue conducting research to put Flexible Tripile into practical use in real-world marine environments.

The company also recognizes the need for further technological development in offshore wind power to achieve the carbon neutrality goals outlined in J-Power Blue Mission 2050.

“We will help realize a carbon-neutral and hydrogen society. For the future of our beautiful, blue planet, and for the more than seven billion people who live on it,” said J-Power.

The J-POWER Group formulated J-POWER BLUE MISSION 2050 based on the need to expedite its initiatives for climate change. “We will devote our full efforts to expanding CO2-free energy sources, starting with renewable energy, and to developing CO2-free hydrogen.”

The company also stated that it will do its best to carry out the mission that “we will meet people’s needs for energy without fail, and play our part in the sustainable development of Japan and the rest of the world.”

J-Power claimed that for the past 70 years, the company has been providing power Generation Business and consulting services around the world in connection with development of electric power as well as power transformation and transmission facilities, etc.