Wave Energy Primary Drives

         Turbine PTO      &       Direct Drive PTO

   Introducing two practical wave energy conversion designs:  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.  Engineers at 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 Hanna Turbine aims to improve upon the pioneering but inefficient Wells Turbine that was invented over thirty years ago.  In contrast to the Wells, the Hanna Turbine uses asymmetrical airfoils with a lower angle of attack which 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 due to a smaller diameter hub and wider gaps between the high lift blades.  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 more versatile than the Wells, offering three distinct power take-off designs to meet job-specific applications.  It can be scaled up to three meters (9 feet) in diameter.  A 15cm (6 inch) diameter model can provide battery charging power for small autonomous research buoys. 

  Generally, wave energy devices operate in the open ocean.  In comparison, both Hanna technologies operate at sea but also can function as shore based installations.  They can be built into jetties or breakwaters and can be connected directly to the grid. As an alternative, 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 and other renewable energy technologies.  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 maritime traffic, commercial fishing or recreational activities.


  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.  Both of the Hanna PTO's avoid these costly O&R haulouts.  Routine maintenance at sea is possible through weather-tight hatches.  No generating components are immersed in water.


   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 ownership of the patents to an established manufacturer or qualified wave energy developer.


Two models of the 'bent duct' Hanna Turbine    



Senior engineering students at the Oregon Institute of Technology (OIT) have issued a final report on their attempt to compare two wave energy converters: the Wells Turbine and the Hanna Turbine.  Both six-inch diameter devices were tested under identical steady-state air flow conditions with their respective drive shafts connected to a 24 volt DC motor.  The Hanna design can develop high torque values at low RPM.  The Wells reaches peak performance and efficiency at speeds well over 3,000 RPM.  The report states that the Hanna model performed best at around 400-425 RPM.  The OIT researchers said that the Wells model was not even able to overcome the motor's internal resistance and start turning.  The study demonstrated that the Hanna design shows potential to outperform the pioneering Wells design.  The students graduated this June and the OIT/WETGEN contract has expired.  A high-level study is the next step forward.  This could be a ground breaking doctoral thesis for a skilled engineer to compare both wave energy turbines.  Proposals from PhD candidates or prospective partners focused on wave energy and turbo machinery are requested.  Existing academic research and intellectual property will be freely shared.