Wave Energy Power Drives


Direct Drive & Mono-radial Turbine Power Take-Offs 


  Hanna offers three innovative PTO's for wave or tidal energy developers.  End-users can select: (1) the Hanna Mono-radial impulse turbine; (2) a mechanical direct-drive PTO called the Hanna MultiDrive; or (3) the Hanna Bi-directional Tidal Turbine.


  A fourth invention, the Hanna Impulse/Reaction Turbine, was sold to HydroWing/Tocardo, a multi-national tidal developer in January, 2020. The patent, U.S. 8,358,026, has a unique drive train which allows the turbine to be utilized either as a wave energy converter or as a bi-directional, cross-flow tidal energy converter.  Additional information is on the John Clark Hanna LinkedIn page. 


  The Hanna Mono-radial wave turbine harvests energy from the up and down movement of ocean waves by means of the OWC (Oscillating Water Column) principle.  OWC technologies are the most mature and well-studied wave conversion systems in the marine energy sector.

  The simple and robust Hanna Mono-radial turbine was designed to outperform all other impulse or reaction-type turbines in the wave energy marketplace.  In contrast to these other designs, the Hanna Mono-radial Turbine has a larger rotor with peripheral collector vanes.  The rotor and generator efficiently spin in one continuous direction regardless of the bi-directional air flows. The spinning rotor acts like a flywheel, utilizing its angular momentum to develop high torque values.  The Hanna Mono-radial does not "stall" like the pioneering Wells Turbine.  It self-starts easily and can function over a wider bandwidth.  The turbine's unique air cored, axial flux generator offers lower magnetic drag than the competitors' iron cored generators.  The special generator is easily accessible and will operate in a dry or submerged environment.  


  The patented MultiDrive, U.S. 8,745,981, is a mechanical direct-drive PTO which converts linear, bi-directional motion into a one-way rotary motion.  The MultiDrive PTO serves shore-based installations, surface buoys or subsurface power buoys that are hidden from view. The subsurface MultiDrive system is energized by pressure differentials that exist between the surface and the submerged buoy's lowest point.  This allows a wave's energy to be harvested efficiently without the need for complicated and expensive phase control strategies.  Because the entire wave converter is below the surface, it is never exposed to destructive storms; it can be built of lighter materials and only uses a taught-line three-point mooring system.  These factors combined represent significant cost savings, lowering LCOE dramatically.


  Both the Hanna Mono-radial turbine and the Hanna MultiDrive PTO can be placed on breakwaters or jetties where they can be easily connected to the grid.  Environmental studies done on existing shore based OWC installations have resulted in FONSI (Findings of no Significant Impact).  Hanna shore based power plants will not interfere with marine life, maritime traffic, commercial fishing or recreational activities.


  For more information on the Hanna Mono-radial Turbine, the patented Hanna MultiDrive PTO or the patent pending Hanna Bi-Directional Tidal Turbine, go to Page Two by clicking HERE.     


     In the foreground, the bi-directional pneumatic Test Stand with experimental Hanna Mono-radial Turbine.  In the background, the Bi-radial Turbine and MultiDrive proof of concept models.