Wave Energy Converters: Engineering Challenges and Opportunities

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Why hasn't wave energy technology gone mainstream yet?
We have been hearing about the potential of wave energy converters (WEC) for decades now, but it hasn't gone mainstream in the same way that wind and solar power have in that same period.
I recently had the opportunity to spend some time surfing, and since I am not the world's best surfer I spent a lot of time getting dumped by waves. This made me painfully aware of how powerful waves are, and it got me wondering why wave energy engineers haven't yet been able to turn this source of renewable energy into a cheap and reliable electricity source.
In this video I discuss:
- how waves form
- what are the characteristics of wave energy
- how does wave energy work?
- what kinds of wave energy conversion devices are available
- what are the engineering challenges associated with wave energy converters
I will be following up with interviews with people working in the wave energy industry to get their insights into what the technical challenges have been and what the future of wave energy might look like.
Check out my full wave energy playlist, which has interviews with wave energy researchers, project managers, mechanical engineers and founders of wave energy companies, plus some other interesting videos on the topic from other creators:
• Wave energy
Footage used:
2:51 Simple harmonic motion Public domain/ user:Evil_saltine
3:45 An OE Buoy designed around the oscillating water column principle. Photo by Ocean Energy Limited, NREL 17873
3:48 Oscillating water column WEC in Port Kembla, Australia. Photo by Oceanlinx, NREL 17208
3:52 Experimental wave tank test. Photo by Yi-Hsiang Yui, NREL 20367
3:54 WET-NZ testing in Oregon. Photo by Northwest Energy Innovations, NREL 25664
3:57 Azura(TM) 20kW point absorber wave energy device prototype in Oahu, Hawai'i. Photo by Northwest Energy Innovations, NREL 46298
3:58 Prototype point absorber near Seattle. Photo by Columbia Power Technologies, NREL 19381
3:59 Wavebob wave energy converter (WEC) oscillating point absorber. Photo by WavebobCo. Louth, NREL 19384
4:00 150 kW PowerBuoy®. Photo by Ocean Power Technologies, NREL 22857
4:03 An OE Buoy designed around the oscillating water column principle. Photo by Ocean Energy Limited, NREL 17874
4:18 Deep water wave Kraaiennest / CC BY-SA (creativecommon...)
4:28 Eco Wave Power www.ecowavepower.com
4:43 Nemos wave energy converter www.nemos.org/...
4:48 BioWAVE bps.energy/
Video editing and animated intro by www.video-gestaltung.de

Опубликовано:

28 сен 2024

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Комментарии : 75

@wimvanuytven7858 2 года назад

Hi Rosie, love the channel. I think I see another fundamental problem that you did not mention. Mechanical power is force x velocity, or torque x rpm. It is mainly the force for which you have to pay in materials, while the velocity or rpm, up to a certain level, comes almost for free. This is why race car engines turn at 10 000 rpm and why jet engines turning at 20 000 rpm have a much higher specific power than IC engines. Also in wind turbines, the blade tips are moving quite fast. In wave technologies, however, we seem to be dealing with low velocities and low frequencies, meaning that high forces are needed for a certain power output, for which you will have to pay in material costs.

@ELMS 3 года назад

Very cool idea to go surfing while presenting. I live on Vancouver Island, in Canada. We have enough wave energy on our west coast to power all of Canada…if we could harness it.

@ljp7447 2 года назад

Nothing better than a surfing Australian Engineer talking about renewable technology!

@nomankhatri. 3 года назад

Really, use of wave energy is need of time. Good and best try. One day we will succeed to use this sea energy as a electric energy inshaallah.

@DarrellW_UK 2 года назад

I’m mega impressed, Rosie surfs and manages to do an article despite one wave dumping her! Yes wave technology is still a bit of a grey area, but can’t you harness power from the tidal movement rather than wave power?

@Alastair510 2 года назад

Apart from some very unique areas in the world, there are very few places where the tide generates much current. I live above a loch with a (on average) 4m tidal range. There is negligible current. 4m is a pretty decent tidal range, so you might be thinking 'why not use tidal barriers and turbines'. A hydro damn installation usually looks for a 'head' of about 20m. That tidal range of 4m I mentioned is tiny by comparison - and you only get that on some days for a few hours (neap tides are only about 1.2m). In summary, tidal power is not going to generate much power without a *huge* tidal dam.

@thekaxmax 2 года назад

That requires specific circumstances to work. High tide level difference and a narrow constraint are needed. And power from this is being done. But it's rare enough not to be significant except locally.

@floydrudolph321 2 года назад

Excellent video. Thanks

@bicyclemanllc 2 года назад

This link has an idea they call "ocean battery". It involves pumping sea water into a bladder deep in the ocean. But depth should not matter because the density of sea water in the system is equal to that outside. Therefore energy would only be stored by the elasticity of the bladder? Why not pump air into deep bladders, then you store energy by stretching the bladder, the difference of density between air and water and the compression of air? This would allow a smaller bladder to store more energy. Or am I missing something? Thanks for all your info!

@DucPham-kd9fz 3 года назад

The main reason why wave energy doesn't pick up yet is the design. The 3 wave's motion mentioned in the video are Heaving, Surging and Tilting, leave them alone ! 65% of wave energy converters are trying to harvest wave energy directly from a moving mechanical part such as a buoy (spot absorber) or flap (surge absorber). This is an intuitive approach that unfortunately leads to mechanical fatigue failure. Instead of changing the concept, engineers are reinforcing the system making it heavier, less sensitive to waves (low capacity factor) and more expensive --> Not competitive. The most reliable way to harvest wave energy is called OWC (Oscillating Water Column) with compressed air as PTO (Power Take Off) --> no moving part is in contact with wave chaotic forces. The only moving part is the air turbine that will convert pneumatic force into electricity. It is basically using waves as an air piston but with plenty of design solutions that makes the overall system lightweight and simple to maintain. Then, there is a significant cost : offshore installation and export cable laying. In the offshore installation method statement, forget about specialized cable lay vessels charging $200k a day. There are smarter ways to install subsea cables without these expensive vessels. Design and installation engineering are the key get a low LCOE (Levelized Cost of Electricity). Check out how the cheapest wave energy from France called HACE (Hydro Air Concept Energy) is working : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1zdryoZz5gg.html - click on CC and settings for EN subtitles. HACE has been selected among the 5 start-up's (over 105 analyzed) that impact hydropower technology : www.startus-insights.com/innovators-guide/5-top-hydropower-startups-impacting-the-energy-industry/ LCOE < $30 / MWh CAPEX = $2.4 M / MW installed OPEX = 5% Capacity factor (guaranteed) > 70% You can find me on LinkedIn using #HACE #waveenergy

@EngineeringwithRosie 3 года назад

Cool, thanks for the tip. I have seen some other oscillating water column designs but not HACE, so I will have to check that out.

@paulh7677 2 года назад

Hi Luc, curious what sort of kW the HACE prototype can produce?

@Alastair510 2 года назад

"In the offshore installation method statement, forget about specialized cable lay vessels charging $200k a day. There are smarter ways to install subsea cables without these expensive vessels." Do tell me about this. The need to lay subsea power cables is growing. I'm extremely skeptical about your claim here. Extraordinary claims require extraordinary (or even 'some') proof.

@richardfraser1562 3 года назад

What a great video. Thanks

@dxb338 3 года назад

3:35 "when the set rolls through and you realize you missed it because you were rabbiting on about wave physics"

@EngineeringwithRosie 3 года назад

So true! I actually filmed most of this while I had a sprained ankle and couldn't stand up anyway. I could only paddle and ride waves on my stomach.

@nandasetiyohadi5063 2 года назад

NIce, I have a new model of wave converter energy with simple tecnology. I have completed the first prototype and the result is this system can capture unstable input to continous rotation. Unfortunately there is no reference about the calculation of this system

@sivamass7518 3 года назад

Great video

@EngineeringwithRosie 3 года назад

Thanks! This one was the most fun to make of all my videos 😀

@Number_Free 3 года назад

Salt water is a fair conductor of electricity, so I have wondered about passing the waves through a strong magnetic field. Not that efficient I expect - but simple, robust and effective perhaps; cheap. In practice, it may be better to funnel a 'salty' wind through a tunnel. I don't want to disturb the marine environment. PS I am sure that I would have loved surfing. Too late now, unless I can start a 'Silver Surfers' club.

@allanliu1314 3 года назад

When talking about wave energy, do engineers just consider the wave from the wind? How about the tidal waves (daily, monthly and typhoon/hurricane surge, or even tsunami), and the planetary under ocean "rivers" such as the gulf stream? Different wave/tide types need different methods/techniques to deal with. Hopefully Engineers like you can figure out solutions for each type of wave/water energy and make it easier to harvest and low cost to start and maintain.

@TheHuesSciTech 3 года назад

Tidal power is totally a thing, you can look it up.

@tjampman 3 года назад

Tides don't really produce waves, so when trying to get power from tides you try to harness the power of the water currents, so the mechanism is completely different.

@palanthis 3 года назад

Great explanations. Very interesting. However, as someone who surfed the north shore of Hawaii for many years, I have to say, I feel bad for you on the day you were filming. I have bigger waves in my bathtub. ;)

@EngineeringwithRosie 3 года назад

I hope one day I can experience Hawaii's waves for myself!! I was pretty happy with these conditions for filming this video though. Nice blue skies in the middle of winter, and mostly clean waves. I was recovering from a sprained ankle at the time I filmed this, so I wasn't allowed to stand up even when I filmed the talking parts, I could just paddle around and ride waves on my stomach and small waves are better for that.

@burtvincent1278 3 года назад

Can you imagine the tidal energy if it could be captured from the Bay of Fundy.

@AlanTheBeast100 3 года назад

That's a joke right? They're shutting down Annapolis and there is a large project in the Minas basin.

@MG-fr3tn 2 года назад

You climb inside it to fix it.

@dprcontracting6299 3 года назад

Whoever met a brainy surfer? Well you have now!

@MG-fr3tn 2 года назад

I didn't understand anything 😅

@timprobst7905 4 года назад

Just for fun, my thoughts on the challenges of WEC (Wave Energy Conversion). The cost! Due to the below variables. 1) Maintenance. Time, equipment and materials to battle the effects of the ocean. Any moving part, or seal doesn't last long. Also, bio fouling. 2) Up front costs. To even attempt to survive ocean life the construction cost to build something to last is $$$. 3) 100 year storm. Surviving the normal ocean conditions is one thing. But any design needs to survive the 100yr store scenario. 4) Efficiency. It's a struggle to capture enough energy in all wave conditions (directional and confused seas) to produce an adequate $/kw ratio. 5) Environmental impact. Anything more than an anchor, and you're going to be fighting at least one enviro group. Noise, vibration and obstruction of wilds life. And eye pollution, of course. It's easy to capture the motions of the ocean, but meeting that $/kw, taking into account all the above has proven more than challenging. If we try to solve the problem backwards/idealistially, then a solution would probably need the following characteristics. 1) As few moving parts as possible. Like one. Ha. 2) No joint seals that could fail. 3) Made with as many off the shelf components or manufacturing methods. 4) Captures energy in multiple axis. 5) Extreamly easy to maintain, clean and repair. And probably a >1yr maintenance cycle. 6) 100yr storm survival. It needs to be able to ride out the worst of the worst. Be it Durability or adaptability. (That's one cup of coffee worth of thought)

@timprobst7905 4 года назад

Oh, and I forgot to clarify that idealistially everything is enclosed inside a fully sealed body. No exposed moving parts. Ha.

@EngineeringwithRosie 3 года назад

Thanks for commenting Tim and I agree that all these are desirable and some of them essential. I think that maybe point 4 is in conflict with points 2 and 5 and maybe also 6, or at least with some designs it could be that focusing on capturing as much of the wave resource as possible results in a more complex system that is less reliable, and less able to withstand extreme weather. My opinion is that simpler is better for wave energy, at least at first until there is a demonstrated history of reliability. I'm seeing this trend in most of the WEC technology being developed today, so I think that is positive. 🌊🌊🌊🌊🌊

@timprobst7905 3 года назад

@@EngineeringwithRosie You're totally right. Capturing in multi axis isn't an important factor (as long as directional waves patterns are consistent). Agreed, simpler is better! Overall $/kw is the primary factor.

@paulh7677 2 года назад

Nice high level analysis. I've been involved with subsea tidal energy projects and they are super tricky with major reliability issues, even in the slightly calmer subsea water.

@JatinRathorenab 2 года назад

it is possible now, my profesor is working over this POINT ABSORBER WAVE ENERGY CONVERSION device, I am also partially in the project cause i am not a research scholar just an btech guy.

@Xyquest 3 года назад

You would think they could capture water at high tides then just run it back to the ocean through a conventional hydro generator. I guess cost and environmental impacts among other issues?

@joshuarosen6242 3 года назад

There have been lots of ideas (the Severn barrage is one that's been talked about most of my life and I'm in my 50s) but your guess is spot on. They are typically very large projects (it would be almost 20km for the Severn barrage) and so expensive but the environmental impact is usually the deal breaker. The mud flats around large estuaries are important habitats here in the UK and presumably elsewhere too. There is no end to human ingenuity but so far, the challenges have been insurmountable.

@alexholden 3 года назад

They already exist. Search for "Rance Tidal Power Station" for one example. In fact tidal water mills date back over a thousand years.

@AshesWindTurbineSimulation 4 года назад

Ha, really cool! And super interesting as always. There are a couple of projects (in research stages) about putting wave energy converters and floating wind turbines together, the ideas being 1) just one structure for two devices 2) the motion of the floater would be reduced by the WEC (and thus beneficial to the fatigue life of the wind turbine). Don't know anything about them but that sounds kind of cool!

@EngineeringwithRosie 4 года назад

I agree, it sounds super cool! I think that could well be the first place we'll see wave energy really go mainstream, when it is combined with other technologies to save on the cost of moorings and electrical cables, or to reduce loads on offshore structures, break waters etc.

@ReevansElectro 3 года назад

A surfer-girl? Wow, who knew all the talents you have.

@EngineeringwithRosie 3 года назад

Talent is too strong a word when it comes to me surfing!!

@hlim431 Год назад

Rosie you need to cover Waveswell they have a unit in King Island which you should visit! Kig island has wind PV and wave energy so it is a unique location

@AMPProf Год назад

yep Butt inside drain, Sewer and Water pipes

@PCRoss2469 2 года назад

Tax deductible surfing trip. Clever !

@MG-fr3tn 2 года назад

If the machine is way out at sea or a reef the public and animals won't mind.

@stormhaven7204 2 года назад

Please tell us about micro hydro power generators

@timprobst7905 4 года назад

Does anyone know of any "active" forums for discussing new ideas for wave energy conversion?

@EngineeringwithRosie 4 года назад

Hi Tim, I don't know a forum like that, but I will post this video on LinkedIn later today, and tag some wave energy experts and ask them to comment. I would love it if you would copy your comment to get the ball rolling, often you can get really good debates with a lot of different expert opinions in a LinkedIn post comments thread! If you connect with me on LinkedIn then I will tag you so you can find the post easily. My LinkedIn profile is linked in my channel banner 😀

@timprobst7905 4 года назад

@@EngineeringwithRosie Well, it's been a couple decades since I've had a LinkedIn account. Ha. But I just set up a new account. 👍

@EngineeringwithRosie 4 года назад

Ha ha, all the cool kids are hanging out LinkedIn, didn't you know 🤣 But seriously, if you want to get a discussion going between experts on a given technology and cover many different perspectives then LinkedIn is a pretty good place for that to happen.

@daviousmaximus6446 2 года назад

Coal was/is too cheap to burn.

@anilsharma-ev2my 3 года назад

So simple we can change energy features in few kilometers in few hours Use atmospheric pressure for creating energy so simple

@EngineeringwithRosie 3 года назад

I am looking forward to seeing the technology you develop to extract this "simple" source of energy 😀

@anilsharma-ev2my 3 года назад

@@EngineeringwithRosie just use an inverted tube which can hold one lakh kilogram so it is under high pressure and this will provide many megawatt energy if making displacement of millimeter 😃😃😃😃😃

@mjkeith8748 3 года назад

Why hasn't 1 design for harnessing wave-power taken off? Why hasn't one idea fully captured the thrust of the wave? Love the question and how you came full circle back to it at the end. Here's a crazy thought -- maybe one of the existing ideas is actually really good -- basically as good we are going to get? Then again, as you're hinting, maybe there's a lot more evolution to come. Of the various wave-power approaches would love to compare in terms of Cost/kWh and then compare against other energy sources --> google says solar is $.06, wind is $.053, and Wave is .09 but do we really know this about wave energy yet?? Here is the quote: The World Renewable Energy Report estimates the cost of wave energy at an average of 9 cents/kWh and tidal and current an average of 8 cents/kWh.

@iareid8255 3 года назад

There are many varied ideas to try and generate electrcity and most of them generate an inferior type of electricity. Because grids work on a balance of load, i.e. demand and input from generators which must match on an instantaneous basis. Unfortunately just about all renewable generation does not have the property. of modulation to meet demand which limits the amount of of this asynchronous generation (i.e. they cannot load follow.) that can be connected to the grid. While many talk of 100% renewable generation this simply cannot work as there is no possibility of matching supply and demand. (It's similar to driving a car with the throttle connected to a device that gives a random variable output, rather than the driver controlling it.) This is the sort of problem that wave generation faces, and that it is relatively weak means it really is not an avenue to follow for grid supply. Of course, an undersea environment is a hostile one for any mechanical device so maintenance would be intensive. Off shore wind generators suffer erosion and hence performance loss of the blades at a much higher rate than onshore and they are well above sea level.. If we really need to produce non CO2 emitting electrical power we are wasting time and effort chasing renewables when the answer has been with us for decades. A mix of large nuclear plants and the more flexibble small modular reactors is the only choice we realistically have.

@aymenjaouani8761 3 года назад

The answer to the question of why wave energy hasn't take off is a crucial one. We need an answer so please keep the good work. By the way, you're a gorgeous engineer ( I hope I'm not embarassing you)

@gnewman18 2 года назад

Thank you, I understand the design challenges much better now.

@mikeclarke952 3 года назад

It's not pretty but probably way more practical: build a concrete funnel, i.e wide at the opening and then narrows to a fixed width. Place the WEC in the channel. Reasoning: Wave shaping and lensing. Force the the random wave pattern into something more predictable and useful. Narrows the best design of the WEC.

@TheHuesSciTech 3 года назад

That seems to be a great way to ruin a nice beach! But seriously though, that approach sounds like it'd be acceptable in so few locations (due to its obtrusiveness) that it might not be worth exploring. Just my 2c though.

@KiteTurbine 3 года назад

Dude. You actually.. Ahhh dude! Noice! So many RE engineers surf. So many of the airborne wind energy engineers kitesurf

@EngineeringwithRosie 3 года назад

I want to try kitesurfing so I can use footage from that in a video about the wind turbine kites! Do you surf too?

@EngineeringwithRosie 3 года назад

I just saw your channel and noticed that is your area of expertise! I never saw any of the same design as yours. Yours are beautiful!

@RodRead 3 года назад

@@EngineeringwithRosie Windsurfing was why I chose Aberdeen for uni. (way back when) Kitesurfing rocks. Snow kiting too. We've got a 10kW Kite Turbine automation project developing over the next year+. Let me know if you want anything on it. I was getting slated by pals for not surfing enough (fair) but this last year I've been windsurfing loads again.

@Rick_Cavallaro 3 года назад

@@EngineeringwithRosie We have a saying in the kitesurfing community... "if you don't learn to kitesurf this year... you'll still suck next year". OK - that might be a bit strong, but you'll be wishing you'd done it sooner. And remember... Safety 3rd!

@EngineeringwithRosie 3 года назад

@@Rick_Cavallaro Yep I've got to do it. I'll see if I can find someone nearby to get a lesson from.

@leo-baker 2 года назад

I’d love to hear you talk about tidal energy. I’m from Melbourne in Australia and I’ve always wondered about why there isn’t tidal energy captured at the mouth of port Phillip bay which displaces tonnes of water each tide change. Cheers!

@EngineeringwithRosie 2 года назад

Tidal is on the list, but it is a long list so not sure when I'll get to it 😂

@thekaxmax 2 года назад

You'd have to block off the harbour entirely, not happening.

@leo-baker 2 года назад

@@thekaxmax why do you think that? I imagined there could be turbines below the depths needed for boats, that could be kept busy by the vast displacement happening constantly. Why do you think you would need to block off the whole harbour? Were you imagining a dam-like construction?

@thekaxmax 2 года назад

@@leo-baker the largest ships require almost the whole depth of the harbour mouth. There's no room.