Science for Society | An inexhaustible source of green energy

Scientists work day in, day out to find solutions to a variety of problems. From new medicines to smart agricultural techniques; our research helps society move forward. But this is not always immediately visible. In the Science for Society section, we share stories about impactful innovations, products, and ideas to show that science works!

There are continuous currents under the surface of the sea as a result of the tide. Research has shown that it is possible to generate renewable energy from these currents using the so-called TidalKite: an underwater device in the Wadden Sea that moves back and forth and generates electricity from the resulting tensile forces. UG associate professor Eize Stamhuis and his colleagues have been involved in the project from the start and have helped to further develop and refine this Dutch invention of SeaQurrent.

SeaQurrent

The idea of using an underwater kite to harvest energy from tidal currents was proposed by Youri Wentzel. He is the founder and current CTO of SeaQurrent, the company that produces and implements the TidalKite. The project’s potential is huge: an inexhaustible source of green energy that has almost no impact on the environment. In the longer term, multiple underwater kites could provide around 50% of the energy consumption of the Wadden Sea Islands. Worldwide, there is enormous potential for the TidalKite; in time, the system could provide green power to millions of households and businesses. This idea strongly appeals to the imagination, and SeaQurrent succeeded in securing public and private investors, including EIT InnoEnergy, PMH Investments, Invest-NL, FOM (the Frisian Development Agency) and NOM—the Northern Netherlands Development Agency. In addition to investors, SeaQurrent was also in need of partners who could make the TidalKite more technologically efficient and therefore more commercially viable. That is when the UG entered the scene, and in particular the Energy and Sustainability Research Institute Groningen (ESRIG) that Stamhuis is a part of.

‘A crazy idea is a good idea’

Stamhuis was and is excited. He definitely saw the potential of the TidalKite project, not just because of the renewable energy aspect but also because Stamhuis himself has similar inventions to his name. He is associate professor of Experimental Marine Zoology and Biomimetics, which means that he studies remarkable characteristics of animals in his capacity as both biologist and physicist and applies these characteristics to technological innovations. He studied the wingbeat of the albatross, for example, and used this bird’s technique to make the blades of a wind turbine more efficient. The commercial/business side of SeaQurrent is not exactly Stamhuis’ strong suit, but the technological side definitely is. Stamhuis: ‘I love to think outside the box. A crazy idea is often a good idea! That appeals to me.’

Wind tunnels and flow tanks

Stamhuis: ‘We’ve been involved in the project for quite some time. The first time we were in touch with Youri [Wentzel] was back in 2015. I knew instantly that the idea should work in theory, but the question was: how can we make it happen in practice? We have been able to help SeaQurrent in the field of fluid mechanics in particular, as the company does not have all the required know-how and facilities themselves. Larger companies can afford to set up an R&D department, but a start-up such as SeaQurrent doesn’t have that option. They needed the University. We have wind tunnels and flow tanks available to measure the forces, pressure, and resistance that the TidalKite has to deal with. The University also has powerful computers at the High Performance Computing cluster to perform simulations and calculations. And obviously we have students and PhD students who can conduct research.’

Demonstration model

By now, the UG has been contributing to the development of the TidalKite for over ten years. Stamhuis and his group have helped to adjust the wing-shaped blades and the design of the underwater kite as a whole in such a way that the yield was increased and the system became easier to control. They have run various tests to achieve this and these tests are still ongoing. A TidalKite demonstration model was recently submerged in the Borndiep, a tidal basin between Wadden Sea Islands Ameland and Terschelling. It is a vulnerable nature reserve, which is why they also looked at the effects on the seabed and the underwater life at the site. Any possible consequences for the sea currents and the seabed have also been investigated.

Tweaking

Stamhuis has great confidence in the TidalKite, as do organizations such as the Province of Fryslân, the European Just Transition Fund, and the Wadden Fund. ‘The project is now approaching the advanced maturity phase, after which it can be implemented on a wider scale. What we are working on right now are the final refinements to make the kite even more efficient and affordable. Tweaking, if you will. The concept has big advantages. It is completely carbon-free and, contrary to wind and solar energy, tidal energy is predictable, reliable, and available almost 24 hours a day. It hardly has an impact on the environment and it also doesn’t impair the visual quality of the landscape, because everything is located under water.’

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More information

• Eize Stamhuis
• SeaQurrent