Concept
- Under the action of the swell, a cylindrical floater moves horizontally, a back and forth movement called surge.
- The innovative anchoring system converts this surge into pitch, i.e. a rotational movement of the cylinder around its axis.
- Inside the floater there is a water pendulum at the bottom and two air-filled chambers at the top, separated by an axial vertical divider.
- The rotation of the floater and the movement of the water pendulum will induce cycles of high and low pressure in these chambers and thus generate a flow of air through an orifice connecting them.
- This air flow rotates a turbine directly coupled to a generator to produce electricity. Other applications could be envisaged in the future, such as the production of pressurised water for desalination.
Product
Seaturns develops an innovative wave energy converter:
- Unit power: 200 kW
- Function: electricity production
- Dimensions: Ø 6 m x L 14 m
- Net weight: 35-40 tons
The simple and robust system is designed to withstand hostile conditions and reduce maintenance costs.
The floater is composed of several elements made of welded sheets:
- two coaxial cylinders closed at their ends,
- stiffness partitions,
- an axial vertical divider.
Several floaters can be grouped together to form a wave farm by pooling the anchoring lines.
Seaturns has developed a high-performance energy capture module, protected by two patents. It combines air flow control devices, a high-efficiency air turbine, an electric generator and the associated control system.
Advantage
Robustness
A design focused on simplicity, robustness and compactness gives the floater a comparable durability to that of a buoy. The system does not use pistons, racks, belts, pulleys, end stops, etc. to limit the risk of failure and maintenance costs.
The power take-off (PTO), all electronic components and other sensitive elements are protected from the marine environment by being located inside a completely sealed volume.
Performance
The tank tests highlighted the good energy capture performance of the system.
The innovative patented anchoring system converts wave-induced surge into pitching motion, regardless of wave wavelength. This wide operating range means that it can be used in a large number of sites around the world.
Technical and economic optimisation
Study and simplification of the life cycle stages (manufacturing, transport, installation, maintenance) very early in the design phase. Installation costs are limited by using light and easily available means of intervention at sea. By taking advantage of the experience gained from existing systems, the design choices aim to limit maintenance costs (few mechanisms to be maintained, interchangeable modules).
Power to mass ratio
Seaturns wave technology has one of the best power-to-mass ratios in the world, making it more competitive and optimising CAPEX (capital expenditure).
High-power wave farm
To meet high power requirements, several generating units can be installed on the same mooring line.
This multi-floater configuration optimises installation costs, makes it possible to build farms of several tens or hundreds of MW, and helps minimize the maritime footprint.
Reduced dimensions
Each floater measures 6 m in diameter and 14 m in length. These reduced dimensions mean that the floats have a low visual impact and limit development and prototyping costs.