Summary
With the Earth’s atmosphere being effectively just a less dense fluid than the oceans around us, it’s reasonable to ask why we got wind turbines and wind mills quite literally everywhere across the globe to harvest the power in the wind, whereas ocean waves and currents aren’t being exploited quite as much. In a recent video by [Giordano Scarciotti] this issue with wave power is addressed, in particular the massive engineering challenges involved.
One of the main problems is simply one of cost, with wind energy having converged on a single design involving effectively the same three-bladed rotor, gondola and tower design that has been optimized for decades now. For wave energy there’s no such one-design-fits-all solution, with each attempted design having its own advantages and disadvantages that may prevent it from working in various sites, or incur high maintenance costs in the highly abusive marine environment.
Having more energy in waves than in wind is also both a benefit and a curse, as wave turbines have to work with the waves and not get demolished every time there’s a storm. Even wind turbines regularly fail in windy weather when e.g. the brakes fail, under conditions that would be considered mild in a marine context.
Also covered in the video is a new contender, in the form of CorPower Ocean’s new buoy-like design that bobs up and down on the surface. Here you need to carefully tune the turbine mechanism to work with the wave motion to extract the most energy. Their current design is be 19 meters tall, 9 meters wide and claimed to be capable of being installed in >40 meter deep water, producing power with a 40-60% capacity factor at 300 kW.
As yet another attempt at making wave energy turbines work, the most exciting aspect of it will be to see whether it can survive adverse weather, when careful tuning gets tossed out of the window and chaotic waves pummel what is essentially a very big hollow buoy. The single prototype has so far survived bad weather off the coast of Portugal during a year of testing, but the real test is long-term survival, as losing half your wave turbine farm to a really bad storm every five-odd years would quickly scuttle the project like it has previous commercial contesters.
Although not addressed in the video, the commercial challenge here is also not so much making the power generated over its lifetime (LCoE) economically attractive, but also its system integration cost in terms of required transmission lines, grid-level energy storage and backup power generators like baseload and standby power plants. Without equipping these wave power farms with grid-forming converters as TSOs are asking, dealing with reactive power to absorb and generate it, any resulting grid oscillations exacerbated by grid-following converters risk causing another expensive blackout as recently on the Iberian peninsula.
I remember seeing illustrations of schemes for accomplishing this in books in the 1970s, all kinds of fanciful notions. Building stuff that sits in the ocean long-term is very challenging, especially if you don’t have a sailor with a mop and a paintbrush on board to go around every day looking for little bits of damage or corrosion. Perhaps we could invent some kind of robo-swabbie…
Wave energy – aside from tidal power – is indirect wind power with conversion losses. The only advantage is a larger “collection area”, offset by the much greater difficulty of capturing the resulting waves at all.
In terms of unit size, if the largest of the wave power generator is 0.3 MW, the top of the line wind turbines are 25 MW. The technology potential for wave energy is basically stuck in the 1980’s in comparison to wind power. In the end, it’s not even a question of technology so much as location: off-shore wind turbines get the same 40-60% capacity factor where there’s steady winds. If the wave generators are put in the same locations, they could generate an additional 1-5% more power.
It’s an interesting technological challenge, but the potential for actual energy production is negligible. It’s more of a subsidy mill for research and development than anything you could take seriously so far.
Everything is indirect solar power with conversion losses actually. Even stuff like nuclear is just solar power from a star that died an unimaginably long time ago
Why stop there? Everything is just recycled Big Bang?
Judging by the number of failed wave and tidal power attempts littering the ocean floor around supposedly-ideal locations (like Bay of Fundy), wave and tidal power is like fusion: The way of the future, and always will be.
I think you meant “wave of the future”.
“Final frontier of renewable energy”?
Nah, we still have to do solar power satellites, a moon array, ionospheric “hooks”, and zero-point…. not to mention the eminently mundane fusion that’s only a few years away(still).
Dyson sphere
Low-Energy Nuclear Reactions (was previously called “cold fusion”. For some reason they renamed it just like the “House of Saxe-Coburg and Gotha” rebranded).
Sorry I meant to say that LENR is at least a millennium years away.
Let’s try that again.
Sorry I meant to say that LENR is at least a millennium years away.
That is odd I can not reply to myself, odd.