Tidal generator on storm barrier

This Delta storm barrier has been designed to prevent flooding of the low lying land in the event of a North Sea storm surge and it is normally left open until higher tides than normal are forecast.

This allows the tide to flow freely in and out and the tidal generators make use of this flow and the fixed barrier to generate electricity. This new installation is the largest tidal energy project in the Netherlands as well as being the world’s largest commercial tidal installation of five turbines in an array. The company responsible for this installation, Tocardo Tidal Turbines has spent 6 years developing tidal current generators and this installation represents the first full working installation of their latest developments.

The Tocardo turbines come in a variety of sizes to match the operating requirements. Those installed on the storm barrier are each rated at around 200 kW and use a direct drive from the propeller to the permanent magnet generator. The twin bladed propeller is shaped to a patented design that allows it to operate efficiently in the flow from either direction and is made from composites. The blade length is varied according to the expected rate of current flow. By installing five turbines, this pioneering installation will generate around 1.2 MW and Tocardo claims that it is simpler and easier to install five smaller turbines that one larger one of the same total capacity.

The foundation system of the storm barrier was specially designed for this project in such a way that the storm barrier constantly remains fully operational. This initial installation only uses one arch of the extensive barrier leaving scope for more similar installations along its length. Special care was given to the environmental challenges around this operation as the Oosterschelde is a protected area and monitoring will therefore be an important part of the project.

On this project Tocardo worked with a series of partners including co-shareholder Huisman who designed the suspension system for the turbines. Strukton was responsible for the project planning and management with Mammoet providing much of the installation transport and lifting hardware. The project will generate electricity for approximately 1000 Dutch households.

“This project is an important step in the development of tidal energy,” commented the CEO of Tocardo, Hans van Breugel. “Tidal technology is innovative and could grow into a significant Dutch export product. With our turbines in the Eastern Schelte storm surge barrier we can show the World what tidal energy is all about, namely providing a clean and reliable source of energy that could fulfil 10 to 20% of the world’s electricity needs.”

By Dag Pike