Texel Wave Energy Pilot

The Slow Mill is a Wave Energy Converter consisting of a floater with blades variably connected to an anchor on the seabed. Waves push the floater up and the blades away from the anchor. This way, not only the up and down movement but also the back and forth movement of the waves is utilised. The blades go as deep as 3-4 m to extract wave power from below the surface as well. 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.

The project began in 2018 as a three year plan to demonstrate the Slow Mill wave energy converter technology with an estimated cost of 4 million euros, 2.5 million of which were granted from the Wadden Fund. The deployment was part of a larger plan to power the Island of Texel with wave energy farms which at the time was estimated to require 10% Texels coastline, and eventually the whole of the Frisian islands in the same manner.

Plans were quickly set into motion with the deployment of a 50 tonne concrete anchor sunk roughly 4 kilometers off of Texels coastline in December of 2018 for later use with the 1:2.5 scale 40 kW pilot device dubbed "Slow Mill-40". The early launch of the anchor was used to determine the stability of its deployment as well as its impact on the local environment which was shown to increase life in the area. The actual Slow Mill-40 was commissioned for construction and 2020 and deployed for trials in 2022.

The demonstration was completed by 2024 with the removal of the Slow Mill-40 for dry bench testing and shortly after the concrete anchor. Both components were deployed again at an offshore site in Scheveningen once the dry tests were completed. Testing will be used to inform the developers of adjustments needed to the device for a 1:1 scale device currently planned to have a 400 kilowatt capacity.