E35 Evopod Tidal Turbine
Evopod 'E1' in Portugal
Evopod Tidal Turbine
Evopod Mono Tidal Turbine
Evopod Tidal Turbine
Evopod Twin Tidal Turbine
Multi-Turbine Tidal Power Barrage
1200kW turbine design

Evopod™ is a floating tidal stream turbine and therefore has low cost of intervention in the event of component failure. Component failure is inevitable in a multi-device farm installation and intervention must be simple, cheap and fast. Floating solutions overcome the disadvantages of bottom mounted devices. Floating solutions are more accessible for first line maintenance and, with the Evopod™ patented disconnectable mooring and power export solution, easily recoverable to sheltered water for servicing or repair activities.

It is important that the floating platform supporting the turbines does not pick up motions from passing waves and that the turbine can be kept away from wave action in average sea conditions. Evopod™, unlike surface floating platforms, has small waterplane area struts and a deeply submerged nacelle ensure low motion characteristics. The streamline struts avoid wake interference with the turbine.

Evopod™ is tethered to the seabed using a catenary spread mooring system with simple pin-pile or gravity anchors. Mono and twin turbine Evopod™ units for deployment at coastal sites exposed to harsh wave climates employ a swivel mooring connection that allows the free floating device to maintain optimum heading into the direction of flow.

The multi-turbine support platform for more sheltered estuarine conditions is moored fore and aft and allows access and removal of individual turbines for maintenance. The mooring and ballasting arrangement can cope with large changes in tidal elevation and can provide a more environmentally acceptable solution than barrages for exploiting tidal estuaries.

Novel Features

  • Patented low motion hull form (UK Patent No. GB 2422878, USA Patent No. 7,541,688 and South Africa Patent No. 2007/3743)
  • High efficiency large diameter turbine(s)
  • Simple but effective mooring system that allows the device to maintain an optimum heading to the tidal stream (UK Patent GB2450962)
  • Power train solution that makes maximum use of standard power generation components
  • Floating platform deployment and hook-up solution (UK Patent application GB2544282)

Key discriminators

  • Designed for efficient operation in exposed sea areas where waves coexist with tidal current.
  • Can be easily disconnected from its mooring system and removed off-site for essential maintenance in safe sheltered non-tidal areas.
  • Does not require a level seabed or long duration, expensive and risky installation operations as required for fixed seabed mounted devices.
  • Overall improved economics of power production compared to bottom mounted devices through lower installation costs and greater annual generating uptime through better access for repair in the event of component failure.

Mono-turbine Evopod™

Evopod™ mono-turbines have been deployed at tidal sites from 2008. Initial deployment was our 1:10th scale unit at Strangford Narrows, Northern Ireland. This unit is currently supplying test data at the University of the Algarve's tidal test site at Ria Formosa, Portugal.

In August 2014 Oceanflow Energy's Scottish subsidiary company Oceanflow Development Ltd deployed its 1/4th scale mono-turbine Evopod in Sanda Sound, Scotland. The 37kW rated output Evopod was deployed at Sanda Sound for 13 months in 20m water depth where the flow speed is up to 4.5 knots. The deployment followed extensive environmental surveys of the area including seabird and marine wildlife which were carried out over 2010/11. The change in subsidy regime in the UK led to the project being cancelled and the turbine and mooring system was decommissioned in September 2017. The project demonstrated the high survivability of the Evopod™ platform at this very exposed site.

Twin and Multi Turbine Evopod™

The development of twin turbine and multi-turbine Evopod™ solutions is in progress. Model tests on a 2.4 MW twin turbine solution were carried out at Newcastle University's flume tank backed up by extensive simulations using the OrcaFlex mooring simulation package.

Turbine machinery

Oceanflow has designed and built turbine machinery for its own demonstration tidal stream turbines and for third parties wanting small instrumented turbines for research purposes. The company has detailed designs for:

  • 1kW geared fixed pitch turbine with a permanent magnet generator
  • 37kW geared fixed pitch turbine with an induction generator and PWM drive control
  • 600kW geared variable pitch turbine with an induction generator and PWM drive control
  • 1200kW geared variable pitch turbine with an induction generator and PWM drive control