Flying the currents below the sea to power homes

As the saying goes, sometimes an idea is so crazy, it just might work. In 1752, Benjamin decided to fly a kite in a thunderstorm to conduct lightning-generated electricity. Almost 300 years later, TopDutch startup SeaQurrent added a little twist to this kite experiment. Instead of climbing up a church tower, they went to the bottom of the sea. And instead of lightning, they use tidal currents. With a €4.8M investment and a promising pilot, a single underwater kite could soon provide enough electricity to power 700 households for an entire year.

In 2016, Youri Wentzel, Maarten Berkhout and Maurits Alberda decided to harness the power of the tides to generate green and renewable energy. To do just that, their Frisian startup SeaQurrent invented the Tidalkite. It’s a multi-wing underwater kite, attached to a pole in the seabed, flying underwater, squarely against the current. 

In fact, it’s pretty similar to flying a kite on the beach. Just like an ordinary kite, the Tidalkite moves with the current from left to right. The kite consists of several wings, and the pulling force drives a hydro motor, which in turn drives a generator, thereby generating green energy. A power cable delivers the energy ashore and because the kite floats 3 meters below the surface of the water, it’s invisible to the eye and can be installed fairly close to shore.

The missing link

The amount of power a Tidalkite can generate depends on the size of the kite and the flow rate. The kite currently being built measures 12 by 7 meters and can generate enough power for 700 households, according to SeaQurrent. Though that may sound like a lot, a large wind turbine can generate 10 times as much energy. But SeaQurrent never intended the Tidalkite to be the end-all solution, but rather sees it as the missing link in our green energy needs.

That’s because the biggest drawback of solar and wind energy is the simple fact that you need the sun and wind to generate power. They’re not always there. But the tides are. And they’re predictable down to the minute, making it a great, dependable and green fit alongside solar and wind. The added benefit is that, unlike the towering wind farms, the Tidalkite doesn’t spoil the ocean views for people enjoying a day on the beach.  

A €4.8M investment

In November 2022, the start-up announced it had successfully closed a €4.8 million investment round. SeaQurrent is currently working on its fourth prototype. A smaller-scale model was built and tested a small model at MARIN in Wageningen, a world-renowned institute for hydrodynamic and maritime research. Scale models were also tested in the Wadden Sea, and the start-up is currently developing a system that will be placed completely underwater for the first time and resembles the final intended model the start-up wants to bring to market. This system will be placed near the shores of the Wadden Sea island of Ameland and is expected to power the first households next year.