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 busy setting up at Carderock

    Posted on Thu 22 Sep 2016

    Our August update may be a bit shorter than our prior updates because we are now here at Carderock during Set-up Week implementing our Test Plan with a talented and helpful Carderock crew. We hope to complete our load cell and encoder spot checks tomorrow and then Sean and I (the RTI mechanical team) will be joined by part of our electronics team (Dr. Nathan Weise and Diane Liskey) for the remainder of Set-up Week and all of Test Week. Dr. Weise, who teaches EE at Marquette U. and has built a powerful programmable digital Power Take Off system for our RTI F2 QD 1/20 scale model, has focused on the application of power electronics to Wave Energy for several years. He worked with RTI on the predecessor RTI F1 prototype while previously at the U. of Maine.

    We remain confident that the global wave energy industry will converge on one or more WEC concepts which can utilize this huge global renewable resource (which is several times more concentrated than solar or wind) and produce renewable power at a lower cost than solar or wind. Once major international power equipment companies recognize that a new generation of wave energy converters (WECs) can
    compete with wind power and they can apply their recent marine experience with the rapidly expanding off-shore wind market, they will make the commitments necessary to propel the WEC industry forward.

    RTI believes that WEC technology convergence will lead to deep water, surface deployed, terminator type WECs which intercept and capture maximum heave and surge wave energy per cubic meter of WEC marine vessel employed (for lowest CAPEX). We also believe that the most secure way to protect surface WECs during severe sea states is to flood and submerge their float(s), an internationally patented feature of the RTI F2 QD and other RTI WECs.

    F2 QD during pre-testing conducted at the UMO Alfond W2
    F2 QD during pre-testing conducted at the UMO Alfond W2

  • RTI packed and ready to test

    Posted on Thu 18 Aug 2016

    Team activities have quieted down since we shipped our Pack-Rat on July 18 (photo of RTI principals John Rohrer and Sean Lewis with loaded container), and then finalized our Carderock Test Plan and Technical Submissions at month’s end. Rooms are booked for team members (Dr, Nathan Weise, Diane Liskey, and Michael Macnicoll) who will be joining Sean Lewis and me for Carderock testing. The team is enjoying some well-earned summer vacation which is especially enjoyable here along the southern Maine coast. Because of the time lapse between our pre-testing at the U. of Maine W2 facility and our team’s late September Carderock test date, we are preparing an F2 QD assembly and operating guide.

    This will also be useful for future planned wave tank and open water tests of our 1/20 scale RTI F2 “QD”. The compressed Wave Energy Prize 1/20 scale schedule did not provide the opportunity to fully utilize our numerical model and maximize our wave energy capture efficiency with tank testing (and reduce F2
    CAPEX) using the many adjustable features built into our 1/20 F2 QD model (including drive arm length and orientation, float mass, drag plate depth and surface area, frame submerged depth and seawater ballasting) under multiple random sea conditions. Utilization of composite float or frame components or a reinforced concrete drag plate may lower CAPEX even further.

    One of the most powerful but as yet underutilized features of our RTI F2 QD 1/20 model is the programmable torque controlled motor-generator PTO system developed by our RTI Wave Power Team Marquette University power electronics members (Dr. Nathan Weise, Ramin Katebi, and Drew Maatman). This system allows us to find and program the optimum resistive force applied by our F2 QD float against each wave as it progresses through each individual wave cycle (allowing for example various latching strategies in wave troughs and declutching on wave crests). In future testing it will also allow wave-to-wave adaptive PTO torque control based on the sensed period and amplitude of each oncoming wave.

  • RTI completes shakedown testing and is ready for Carderock

    Posted on Fri 15 Jul 2016

    June was the first month in the water for our RTI F2 QD. Our “first splash” and “first waves” were in the UNH Chase Labs deep tank and wave tank, respectively (RTI Teammates Toby Dewhurst and Sean Lewis in lower left, setting up for “first waves”). All key components arrived in time for a final assembly by mid-June. A special thanks to team sponsors Sensata-BEI (providing marine grade high resolution encoders), Interface (submersible Load Cells) and UNH Chase Labs (wave tank access).

    A successful series of shakedown and preliminary performance tests were conducted in late June at the U. of Maine, Alfond W2 Wind-Wave Facility in Orono Maine (photo lower right). This new world class wave tank facility with its 5 meter depth and Edinburgh Engineering wave makers allowed us to more closely simulate the ONR Carderock Mask basin Wave Energy Prize test conditions. Apparently many of the 9 Finalists also discovered this facility with others testing before and after us. This was the first time our electrical and control system (developed by our Marquette U. E&C group of Drew Maatman and Ramin Katebi under Dr. Nathan Weise plus Diane Liskey) was merged with our RTI F2 QD hydrodynamic and mechanical hardware numerically modeled, designed and fabricated by our Maine/New Hampshire group of Sean Lewis, Toby Dewhurst, Dick Akers, Mike Macnicoll and yours truly, John Rohrer).

    Convergence on the most cost effective ocean survivable Wave Energy Converter (WEC) configuration (a major objective of the Wave Energy Prize) is essential before the nascent WEC industry can effectively tap the huge global wave energy resource which has several times more energy density than the solar and wind energy which produces ocean waves. We continue to believe this WEC convergence is pointing towards surface deployed elongated wave terminator type WECs intercepting maximum wave front using minimum vessel volume (and cost). The patented RTI F2 QD is the only such WEC which floods and totally submerges its elongated surface float safely below the troughs of even 15 meter high waves for secure survival in seas which would destroy other surface WECs.

  • RTI preparing for shakedown test at University of Maine

    Posted on Sun 19 Jun 2016

    The pace of activity to complete and pre-test our 1/20 scale model has continued to accelerate this month as we recently completed our Carderock Test Plan and other TG3 submissions and are now preparing our 1/20 scale RTI F2 QD prototype Which Sean Lewis and I will take to the new world class U. of Maine, Orono W2 (wind & wave) Facility for several days of shakedown tests.

    Dr. Nathan Weise (formerly with U. of Maine and now with Marquette) has been busy preparing our NI Lab View based programmable motor-generator control system with assistance from 2 of his Power Electronics students, Andrew Maatman and Kamin Katebi. They have been working with duplicate sensors and a duplicate motor-generator but will connect to our 1/20 scale prototype for the U. of Maine tank pre-testing next week joining our east coast EE Diane Liskey there.

    Our prototype is essentially complete but we wish we had more time to pre-test and optimize its performance. Our hydrodynamics and modeling team (Richard Akers, Toby Dewhurst, and Michael Macnicoll) have provided simulation modeling insights as to what model settings should yield the best results (using PTO resistive force, float and frame weight distribution, drag plate depth, and other adjustable parameters on our 1/20 model).

    We remain excited about the inherent high capture efficiency and low capital cost advantages of our patented RTI F2 QD wave energy converter (WEC) technology combined with our submergible Float for maximum severe sea security. We remain convinced that a successful WEC (which can beat solar and wind farm economics) must intercept more wave front (per unit of WEC vessel weight and cost) to capture more wave energy. This requires a self-orienting WEC with an elongated wave front parallel float deployed on the ocean surface in deep water (where wave energy is greatest) capturing a majority of both heave and surge wave energy.

  • 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

DISCLAIMER: The team information provided on this page is provided solely by RTI Wave Power. The Wave Energy Prize is not responsible for its accuracy, legality, decency of material or intellectual-property compliance.

Back to Teams

EERE. Wave Energy Prize. U.S. Department of Energy. Jul, 2018, 13:24 EST. Available at: https://waveenergyprize.org/. Accessed Jul, 2018.

EERE. "Wave Energy Prize." waveenergyprize.org. U.S. Department of Energy, July. 2018. Web. July. 2018.

EERE. "Wave Energy Prize," waveenergyprize.org, U.S. Department of Energy, https://waveenergyprize.org/ (accessed Jul, 2018).

EERE. Wave Energy Prize [Internet]. waveenergyprize.org; 2018 July, 13:24 EST [cited 2018 July]. Available from: https://waveenergyprize.org/

@ONLINE{U.S. Department of Energy:2018:Online, author = {EERE}, title = {Wave Energy Prize [email protected]}}, year = {2018}, url = {https://waveenergyprize.org/}, note = [Online; accessed Jul-2018] }