RTI Wave Power

York, ME

Team Photo for RTI Wave Power

Date Accepted

Wed 24 Jun 2015

Combined Score

5.5 (Technology Gate 2}

Team Info

The RTI Wave Power team will be led by John W. Rohrer.

RTI has been developing and wave tank testing advanced wave energy technologies for the past 7 years and holds several U. S. wave energy Patents. The Team will use the RTI F2/F2D wave energy technology as described in U. S. Patent 8,614,520 and U. S. Published Application No. 2015/00082785. The team will be supplemented in the PTO power electronics and data acquisition area by industry and independent electrical engineering representatives.

WEC Device Type

Wave terminator using floodable/submergable elongated wave front parallel float.

Team Quote

Wave Energy will ultimately deliver global renewable power at a cost below that of the solar and wind energy which produces ocean waves because wave energy is a more concentrated and consistent renewable energy resource. Wave Energy Converters (WECs), however, will have to be lighter to be cheaper than offshore wind farms, now a multi-billion $/year global business. WEC technology development is unique among renewables because there are literally hundreds of unique, distinct, even ingenious ways to convert ocean waves into renewable power. There will only be one deep water deployable, utility scalable, “BEST WEC”, however, producing the lowest Levelized Cost of Energy (LCOE). Costly premature scale-ups of early generation WECs, prior to convergence on a “BEST WEC” technology has wasted public and private investment, caused the collapse of early pioneer WEC developers, and delayed necessary participation of large global power equipment companies and off-shore wind farm developers.

Team Bios

John W. Rohrer (BSME, Villanova; MBA, Wharton; Capt., USMC ) is founder and president of RTI Wave Energy. As VP of Engineering and Project Development of Wheelabrator Technologies and then Zurn Nepco Mr. Rohrer participated in the development, financing, design, construction, and operations of over 1,000 MW of renewable power plant (fueled by refuse or wood waste), valued at over $4 Billion, plus over 1,000 MW of gas turbine combined cycle co-generation plants. Mr. Rohrer holds 14 U. S. Patents, including 3 in wave energy with numerous additional U. S. and international applications pending.

Sean Lewis (BSME, U. of So. Florida) is Director of Engineering and a partner of RTI Wave Energy. He was previously Principal Mechanical Engineer of BAE Systems, Nashua, NH working in defensive aero countermeasures, and Product Team Leader at Raytheon Missile Systems, Tucson, AZ.


RTI Wave Energy is a unit of Rohrer Technology, Inc., a Maine Corporation which holds all patents and intellectual property of its founder, John w. Rohrer. RTI wave energy has focused exclusively on development and wave tank testing of cost effective Wave Energy converters during the past 7 years. RTI Wave Energy is primarily self-funded with patent royalties. RTI Wave Energy was awarded 3 Maine Technology Institute Seed Grants (50%/50% cost sharing) for prototype wave tank testing and WEC numerical analysis work at the U. of NH, Chase Labs and U. Maine, Orono.

  • RTI Team Leader proud of his “all volunteer army”

    Posted on Fri 13 May 2016

    April was our Team’s “finalize design and order components” month. May is our “build and assemble” month so we can hit the wave tanks in June. We plan to utilize the UNH Chase Labs tank first for some initial shakedown trials. Its limited depth, however, requires us to finish our RTI F2 QD 1/20 model testing and tuning at the new U. Maine, Orono Wind-Wave (W2) Alfond facility with its 5 meter depth and state of the art Edinburgh digital wave makers. Our local fabrication and welding shops have done a great job with our 1.4 meter wide Float and Drag Plates. Next week they will be working on our twin vertical Spar Frame and our two watertight PTO housings (holding our motor-generator, gear reduction drives and encoders).

    Nathan Weise and our RTI Electronics & Controls group (Diane Liskey, Rick Sparrold, Siavash Pakdelian, and Mahshid Amirabadi) are working with National Instruments Field Engineer, Peter Rifkin to assemble our DAQ and Programmable Control system.

    Our Hydrodynamics & Simulation group (Dick Akers, Toby Dewhurst, and Michael Macnicoll) have our new 1/20 scale RTI F2 QD model up and going and are optimizing Float and Frame weight distributions, water plane areas and lots of other cool CFD stuff which I honestly do not fully understand.

    As Team Leader I am proud of the work and accomplishments of our entire “All Volunteer Army”. The F2 QD is the 10th Generation of WEC RTI has developed and wave tank tested over the past 7 years. Wave Energy has an intrinsic cost advantage over solar and wind because it utilizes a renewable resource with several times higher energy density. We are hopeful that the Wave Energy Prize will provide the convergence needed on the most economically viable WEC concept(s) to make Wave Energy attractive to global global power equipment producers and renewables project developers which will turn wave energy into a major renewables industry.

  • RTI welcomes new team members

    Posted on Fri 15 Apr 2016

    Our team hydrodynamics and simulation (H&S) group (Toby Dewhurst, Michael Macnicoll, and Dick Ackers) continue to calibrate, refine and crunch our RTI F2 QD models to provide design inputs for our 1/20 model to our mechanical design and fabrication (M&F) group (Sean Lewis and John Rohrer). The M&F group is finalizing shop drawings and has started working with local fabrication shops on Float, Frame, and Drive components.

    With our 1/20 scale RTI F2 QD we are attempting a more complex and ambitious PTO control system which should pay dividends in even higher wave energy capture efficiencies than those obtained in our 1/50 scale official Wave Energy Prize wave tank testing. Our Electronics and Controls (E&C) group has, therefore, been expanded. Dr. Nathan Weise, Asst. Prof. of ECE at Marquette has joined us (in spite of the fact that my undergraduate Alma Mata, Villanova, dominated Marquette and Big East basketball this year and went on to win their 2nd National Championship title in March). Nathan previously headed up the Power Electronics group at U. of Maine, where he and several students successfullydeveloped the rotary electric generator PTO for our prior generation RTI F1 WEC. Also joining our team is Dr. Siavash Pakdelian, Asst. Prof. of ECE at U. Mass, Lowell. While previously at Texas A&M he worked on MHK PTOs including those using magnetic gearing. Welcome back to wave energy and thank you for assisting us in selecting our 1/20 scale generators. Our third E&C group addition is Dr. Mahshid Amirabadi, Asst. Prof. of ECE at Northeastern, where she is part of a strong power electronics department. Diane Liskey and Rick Sparold welcome the new E&C group help.

    Dr. Nathan Weise Dr. Siavash Pakdelian Dr. Mahshid Amirabadi
    Dr. Nathan Weise Dr. Siavash Pakdelian Dr. Mahshid Amirabadi
    Check out the April 3rd story on RTI: http://www.fosters.com/article/20160403/NEWS/160409904
  • RTI Wave Power celebrates and then gets back to work

    Posted on Mon 21 Mar 2016

    A brief team celebration followed the March 1 Wave Energy Prize announcement of Finalists. Soon thereafter, however, reality set in with lots of work before us between now and July 18 to do our promising RTI F2 QD WEC technology justice. Sean Lewis of our RTI “mechanical team” has produced initial CAD 3D drawings of our 1/20 RTI F2 QD prototype. It is designed such that most key dimensions (and weight distributions) effecting performance can be modified as our RTI “hydrodynamics team” (Dick Ackers, Michael Macnicoll, and Toby Dewhurst) refine our F2 QD numerical model with the excellent data obtained during the Prize 1/50 scale test week at the new U. Maine Alfond W2 (Wind-Wave) Facility and use our updated model to optimize 1/20 scale F2 QD performance. We are one of several Wave Energy Prize teams who booked 1/20 scale model wave tank testing time at the Alfond W2 Facility.

    We were sorry to learn that Justin Stocker, the leader of our RTI “electronics & controls” team, will play a more limited role as he relocates to the west coast. We are pleased, however, that Rick Sparrold has joined our E&C team. Rick is recently retired from Raytheon Missile Systems where he was Senior Principal Electrical Engineer and spent his entire professional career after graduating from U. of Arizona as an EE. We are also considering additional electronics & controls team additions as we attempt to implement a challenging “adaptive control” strategy for our 1/20 scale RTI F2 QD.

    Rohrer Technologies, Inc. (RTI) has previously successfully built and wave tank tested two 1/25 scale RTI prior generation WECs (the G2 and F1) which preceded the F2 QD but they used less complex control systems and more comfortable time schedules.

  • RTI Wave Power designs for simplicity and cost

    Posted on Wed 10 Feb 2016

    Our RTI Wave Power Team was fortunate to complete its 1/50 scale model testing at the new U. of Maine Alfond Wind-Wave (W2) Facility on December 18th giving the team time over the Holidays to enjoy some well-earned relaxation.

    While the 1/50 scale modeling, design, build, and test schedule did not afford us the opportunity to test a fully optimized design, we were extremely pleased with our model performance during test week. In early January we started the design of our 1/20 scale model and specifying key components with longer delivery times. We look forward to receiving our test week data set so we can confirm the accuracy of our numerical model and use it to further improve our 1/20 scale model RTI F2 QD.

    Our WEC design features the simplicity and low cost of a single elongated wave front parallel surface float (which remains parallel to oncoming wave fronts). The F2 QD moves both upward and rearward on wave crests and forward and downward on ensuing wave troughs (for concurrent multi-mode heave and surge energy capture). Our patented float can be partially seawater flooded (to tune float mass to current wave conditions). It is fully flooded in severe seas allowing the float to rotate on its two swing arms (which are attached to our direct drive generator housed below the water line in our twin vertical spar frame) to the 6 o’clock position safely below wave troughs even in 25 meter seas. Our concave float rear surface, extending into its attached lower shoaling lip extension, protrudes deeply into the water column yet its motion creates no energy robbing “back wave”. This patented configuration provides major performance and cost advantages over other WECs using elongated wave front parallel surface floats (like the Salter Duck, Stingray, and Azura) which require massive costly central cylinders (or circular section floats).

    RTI F2 QD 1/50 scale going through paces during Wave Energy Prize test week
    RTI F2 QD 1/50 scale going through paces during Wave Energy Prize test week

  • RTI Wave Power first team tested at U of Maine facility

    Posted on Wed 13 Jan 2016

    The RTI Wave Power Team completed our testing at the new Alfond W2 (Wind-Wave) Facility at the U. of Maine, Orono during the week of December 14-18. We were the first Wave Energy Prize team to be tested at this new facility (which was just commissioned in November) but all went very well thanks to a talented and dedicated U. of Maine staff under the direction of Prof. Krish Thiagarajan, and Dr. Anthony Viselli. Most of our RTI Team were able to visit the facility for at least a portion of the test week and were as impressed as I was at this new world class facility (perhaps the only facility which can concurrently produce both waves and wind). The 16 paddle digital servo-motor controlled wave maker (designed with the U. of Edinburgh) worked flawlessly as did a novel wave absorption “beach” at the other end of the tank using a novel U. of Maine developed design (with less than 5% wave reflection over a broad wave spectrum).

    We were also pleased with the operation of our RTI F2 “QD” or “Quarter Duck” 1/50 scale model, so called because its function is similar to the famous U. of Edinburgh “Salter Duck” but it uses only 1/4th of the weight and cost of the Duck’s huge central cylinder. This is made possible by RTI’s patented floodable and submergible float technology (providing ultimate severe sea storm protection). The RTI F2 QD appeared to perform as it had in earlier shake-down pre-testing done at the U of New Hampshire Chase Labs facility.

    Pictured above are 3 RTI Wave Power Team members (middle in blue team shirts L to R Diane Liskey, Justin Stocker and John Rohrer) surrounded by U. of Maine Test Team.
    Pictured above are 3 RTI Wave Power Team members (middle in blue team shirts L to R Diane Liskey, Justin Stocker and John Rohrer) surrounded by U. of Maine Test Team.
    RTI F2 QD during pre-testing at U. of New Hampshire, Chase Labs wave tank. UNH Chase Labs, Maine Marine Composites, and Interface Force Measurements are RTI Team sponsors.
    RTI F2 QD during pre-testing at U. of New Hampshire, Chase Labs wave tank. UNH Chase Labs, Maine Marine Composites, and Interface Force Measurements are RTI Team sponsors.

  • RTI Wave Power attends Maine dedication ceremony (video); Explains QD in their WEC configuration

    Posted on Wed 09 Dec 2015

    The RTI Wave Power Team delivered its 1:50 scale RTI F2 “QD” model to the Wave Energy Prize regional test center at the U. of Maine, Orono (UMO) on November 23rd which happened to be the day when UMO was dedicating its new world class wind-wave facility capable of making waves up to 0.7 meter while simultaneously exposing test models (WECs, floating wind turbines, deep water drill rigs, and ships) to gale force winds. Dignitaries on hand included Maine Senators Susan Collins and Angus King as well as DOE Wind and Water Power Director Jose Zayas.

    People have asked what the “QD” represents in our RTI F2 “QD” WEC configuration. Many will recall the “Salter’s Duck” wave terminator type WEC proposed in the 70’s by one of the great pioneers of wave energy, Prof. Stephen Salter of the U. of Edinburgh, which demonstrated extremely high wave energy capture efficiencies (over 80%), even in random seas, but required a large (6-16 meter diameter) expensive central cylinder and complex hydraulic PTO. The RTI F2 QD entirely eliminates Salter’s massive and expensive central cylinder, replacing the incident wave impacting one fourth of the Duck’s cylinder with a comparably sized one quarter cylinder integrated into the F2 QD float; One Fourth the Duck’s cylinder at One Forth its cost with superior performance, hence RTI F2 “Quarter Duck”. The RTI F2 QD maintains RTI’s patented seawater floodable and submergible elongated float for total protection in severe seas.

    Pictured below our talented and dedicated PTO-Electrical Engineering teammates, Diane Liskey and Justin Stocker utilize a high precision T8 torque transducer (provided by team sponsor Interface Advanced Force Measurement) to calibrate our PMDC generator prior to a final pre-test session at UNH Chase Ocean Engineering Labs (another team sponsor).

    RTI team members Diane Liskey and Justin Stocker
    RTI team members Diane Liskey and Justin Stocker
  • RTI Wave Power gives thanks to those that support them

    Posted on Thu 12 Nov 2015

    The RTI Wave Power Team has been working overtime wave tank testing our RTI F2 1/50 scale prototype at the UNH Chase Labs wave tank, and tweaking our design under the guidance of our UNH, Maine Marine Composites, and RTI hydrodynamics team members. Our model making power! The modelers are using wave tank test data to refine our model set-up, an iterative process with limited time to iterate. We look forward to delivering our model to the U. Maine Wave Energy Prize testing site and team at the U. of Maine, Orono, who have been most helpful in communicating what they need to set up and test our model at their facility.

    My thanks to the extraordinary efforts put forth by our entire team of volunteers, allowing us to reach this point (making power and collecting valuable data). Helping Sean Lewis and myself here at RTI Wave Energy (doing model design and fabrication) is our hydrodynamic modeling team (Michael Macnicoll and Dick Akers and Toby Dewhurst and Rob Swift), our Power Take-Off and Data Acquisition engineers (Justin Stocker and Diane Liskey), and our wave tank testing team (Carlos Bezerra plus most of the above).

    Pictured on the “Bridge” of the UNH Chase Labs Wave Tank after a full day of testing on Veteran’s Day is (left to right (Justin Stocker, Toby Dewhurst, Carlos Bezerra, and yours truly John Rohrer. A special thanks goes to our sponsors, UNH Chase Ocean Engineering Labs, Maine Marine Composites, and Interface Advanced Force Measurement.

    RTI testing on Veteran's Day.
    RTI testing on Veteran’s Day.


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Back to Teams

EERE. Wave Energy Prize. U.S. Department of Energy. May, 2016, 12:12 UTC. Available at: http://waveenergyprize.org/. Accessed May, 2016.

EERE. "Wave Energy Prize." waveenergyprize.org. U.S. Department of Energy, May. 2016. Web. May. 2016.

EERE. "Wave Energy Prize," waveenergyprize.org, U.S. Department of Energy, http://waveenergyprize.org/ (accessed May, 2016).

EERE. Wave Energy Prize [Internet]. waveenergyprize.org; 2016 May, 12:12 UTC [cited 2016 May]. Available from: http://waveenergyprize.org/

@ONLINE{U.S. Department of Energy:2016:Online, author = {EERE}, title = {Wave Energy Prize [email protected]}}, year = {2016}, url = http://waveenergyprize.org/}, note = [Online; accessed May-2016] }