Dutch firm’s wave energy tech delivers first kilowatts in North Sea (Gallery)

A wave energy device developed by Dutch wave energy company Slow Mill Sustainable Power has generated electricity from North Sea waves for the first time.

According to Slow Mill Sustainable Power, the wave energy generator was tested off the coast of Scheveningen last week, marking a key milestone in its development.

The technology, designed to work in the North Sea’s relatively low waves, could complement offshore wind farms by utilizing existing infrastructure.

“It was an Eureka moment when the first kilowatts became visible on the dashboard around midnight last week,” said Erwin Meijboom, CEO & Co-founder of Slow Mill Sustainable Power.

“This test was crucial for us. A milestone has been reached. After six years of development, we have demonstrated that our technology really works. I cannot stress enough how important that is. From now on, we can optimize and scale up.”

The company said that it is now focusing on improving efficiency and further offshore testing. Scaling up to wave farms is seen as essential for profitability, with offshore wind sites offering an opportunity to integrate the technology. 

The Slow Mill 40 is a heave-and-surge wave energy converter (WEC) that uses the up-and-down and back-and-forth motion of the waves in the whole water column to produce clean power.

The device works by making use of rotating water particles, as it has been specifically designed to follow this movement and to come into resonance with the wave to convert its energy optimally.

“When the wave recedes, it takes the Slow Mill back to its starting position. The entire unit follows the orbital or sometimes elliptical wave path but, taking the inner bend, moves a bit slower than the wave, hence its name: Slow Mill,” said the company.

In July 2024, Slow Mill Sustainable Power moved its WEC from the harbor in Den Helder, the Netherlands, to the dry testing site.

In June 2022, Slow Mill Sustainable Power completed the engineering and construction of the device, launching it in a harbor.

A few weeks later, the device was towed four kilometers off the coast and released to reach a vertical position with the floater above the water. The device, scaled at 1:2.5, was attached to a 50-tonne concrete anchor installed in 2018, which has been researched for its benefits to local biodiversity.