Schottel Hydro Turbine Solution for Minesto’s Deep Green

Schottel Hydro will deliver a customized turbine solution for Deep Green, an underwater kite construction from the Swedish company Minesto in 2016.

The turbine complements the first full-scale Deep Green device.

The underwater power plant will be deployed in 2017 at the Holyhead Deep site off the coast of Anglesey, Wales.

During the coming three years, 19 more devices will follow and eventually form an array with an overall capacity of 10 MW.

Deep Green allows the harvesting of tidal energy in slower waters which have been thought unproductive so far, with low current velocity of two meters per second and in great depth of 60 to 120 meters.

Deep Green resembles an underwater kite and consists of a wing and a turbine. The kite has a wingspan of 12 meters and is attached by a tether to the sea bed. It moves along a preprogrammed 8-shaped trajectory and thus increases the water current velocity around the kite by its own speedy movements. The attached turbine therefore works with an up to ten times higher current velocity than originally available. The obtained energy is transferred onshore via a cable connection on the seabed.

For Minesto, Schottel Hydro develops a new turbine variant, which should optimally fit the requirements of Deep Green: The light weight nacelle power-take-off system includes turbine, drive train, power electrics and auxiliary devices. According to the company, all components will be tailor-made to fit the electric system of the kite.

The drive train concept is based upon the proven concept of the Schottel Instream Turbine (SIT) with its inline arrangement of open rotor, rotor shaft including sealing and bearing, planetary gearbox and generator. In contrast to this readily available device with rotor diameters between three and five meters the Deep Green turbine will be significantly smaller and operate at higher rpms.

In addition to the turbine engineering and manufacturing, Schottel Hydro will also carry out a full-load test series on a specially built test stand prior to installing the turbine in the third quarter of 2016.

“With Schottel Hydro we found a true one-stop supplier for tailor fitted turbine solutions,” says Anders Jansson, CEO of Minesto. “We are really looking forward to our cooperation at Holyhead Deep.”