German propulsion solutions specialist Schottel, has founded a new subsidiary - Schottel Hydro GmbH. The new company will incorporate Schottel’s hydrokinetic energy business. Schottel Hydro comprises activities in three segments: hydrokinetic turbines, semi-submerged platforms and components, such as turbine hubs and drives.
“For a few years we have been working on the development of highly efficient, reliable and cost-effective solutions for gaining instream energy,“ explained Prof. Dr. Gerhard Jensen, CEO of Schottel. “Schottel Hydro allows us to dedicate even more to hydrokinetic energy solutions. By now we are involved in projects around the world and aim at a full penetration of the emerging hydrokinetic energy market with our solutions and products.“
Schottel hydrokinetic turbines are instream generators, with a rotor diameter between three and five metres. Depending on the current velocity, one turbine produces between 54 and 70 kW rated, grid-ready electric power. Higher power demands are met by combining several turbines in one installation. Each of the turbines is connected to a frequency converter feeding into a common DC bus installed on the tidal platform.
The turbines can be implemented in rivers, sea straits and tidal races offshore in jetty, semi-submerged or submerged platforms in varying numbers. Schottel claim that even the installation at sites with restricted water depth is easy due to the small size of the turbines.
Together with the subsidiary TidalStream Ltd. Schottel Hydro also offers the Triton semi-submerged floating platform. The platform is attached to a gravity-base, drilled pile or pinned frame anchor point. A universal joint allows the platform to align to the direction of the flow. Buoyancy is provided by two spar buoys which hold a variable number of cross arms. The turbines are mounted on the cross arms. The platform is especially maintenance friendly: The electronic system is accessible in the spar buoys and by emptying or filling of ballast tanks the platform easily switches between operating and maintenance position. This platform will be installed in 2016 in the Bay of Fundy, Canada.
Schottel Hydro also offers engineering and manufacturing for in-stream power solutions, e.g. gear boxes, shafts, sealing systems, hub and pitch mechanisms for tidal turbines. Schottel Hydro components can be found, for example, in the three-bladed Andritz-Hydro-Hammerfest HS 1000 turbine. Schottel provided the turbine shaft, shaft sealing, hub and pitch mechanism for this 1 MW tidal generator. The HS 1000 is designed for installation on the seabed at 40 to 100 metre depth in tidal streams. The pitching system allows the generator to switch between generating from tidal currents in both ebb and flood directions.
By Jake Frith
