Wave & Tidal Energy Primary Drives



Turbine PTO, Direct Drive PTO & Closed-Loop PTO 


  Inventor, John Clark Hanna, introduces two wave energy converters for utility-grade power:  the Hanna Turbine known as a WETGEN (Wave Energy Turbine GENerator), U.S. Patent No. 8,358,026 and the Hanna MultiDrive, a mechanical, direct-drive power take-off (PTO), U.S. Patent No. 8,745,981.  Both devices harvest energy from 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 industry.  Oregon State University (OSU) built a small working Hanna Turbine.  The device was tested with a bi-directional air flow.  Acting as an impartial third-party, the OSU College of Engineering issued a final report that validated the Hanna Turbine in 2014.


  The simple and robust Hanna Turbine was designed to improve upon the pioneering Wells Turbine.  In contrast to the thirty year old Wells design, the transformative Hanna Turbine uses asymmetrical airfoils with a lower angle of attack.  This creates more lift and less drag.  The design resists "stall", improves self-starting and can function over a wider bandwidth with higher torque values.  It offers lower damping (restriction) to the bi-directional airstream.  Unlike the Wells, it drives two generators - doubling the power output.  Both generators are easily accessable and operate in a dry environment.  The Hanna Turbine is versatile, offering three distinct power take-off designs to meet job-specific applications. 


  Generally, wave energy devices operate in the open ocean.  This is true for the Hanna Turbine and the Hanna direct-drive PTO.  However, both Hanna designs will also function as shore based installations.  They can be built into existing or purpose-built jetties or breakwaters and can be easily connected to the grid.  All completed EIR studies for 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.


  As an alternative to 'shore based' installations, Hanna 'ocean based' applications can be installed on tethered buoys, the legs of off shore oil rigs, or on floating wind and wave harvesting platforms.  Hanna primary drives can also spin water pumps to support desalination plants. 


  Most deep water designs are sealed up and their generators are inaccesible at sea.  To perform maintenance, the sealed devices must be removed from the water and transported to shore.  Buoy-mounted applications of the Hanna PTO's avoid these costly O&R haulouts.  Routine maintenance on deep water, buoy-mounted PTO's is possible through weather-tight hatches.  No generating components are immersed in water.


  To underscore the remarkable versatility of the WETGEN design, the turbine can be easily modified for use as a tidal energy converter.  Whether applied for wave energy or tidal energy, no other turbine in the global marketplace can serve both of these renewable energy sectors.


  To provide reliable power for littoral and deep water research and data acquisition buoys, Hanna has developed a novel closed-loop pneumatic drive for bi-directional air flows.  For details, click HERE.


   Videos of the Hanna Turbine can be viewed on the WETGEN You Tube channel.  For a more detailed description of the Hanna MultiDrive power take-off, click HERE.  Additional information is posted on John Hanna's LinkedIn page or simply Google WETGEN.


  To assure the responsible development and successful commercialization of both technologies, the inventor seeks to assign full ownership of the patents to an established research entity, manufacturer or qualified wave energy developer.  For more details and to read the "Forward Looking Statement" click HERE.


Test stand and early experimental Hanna Turbines



  As of February, 2017, a hi-level academic study of the Hanna Turbine is currently underway.  This project will advance the turbine's Technology Readiness Level from TRL 2-3 to TRL 6-7. 

  Still active is a call for an MSc or PhD-level candidate to pursue a dissertation on either the Hanna direct-drive PTO or the tidal energy PTO. Please respond to this call if you would like to conduct an original study of either of these primary drives.