I thought I read that wave/tidal was basically not worth the investment and ecological impact for the power it generates.
I remember reading a few papers about essentially underwater turbines in tidal estuaries. Where you have natural flow of water that you can just tap. If I recall correctly impact on local wildlife (seals iirc) was lower than expected.
Main argument I could see was that water had 1000x the density of air so 1000x the amount of power for a rotor with the same swept area. Of course fluid speeds are lower so it’s not quite that easy. But much more predictable. They did some fancy optimisations in the blades and came up with decent efficiencies. It’s a great little series of papers by Batten and Bahaj et. al from 2006.
I assume the art has progressed since then.
But yeah, anything with moving parts in seawater is a nightmare as far as I can tell.
That would mean we’d be well into the type 1 civilisation about 10^19W a year and we’ll be on the way to a type 2 civilisation.
There may be some neat tricks, this is an area I know I'm not good at, but you have to be very careful.
SF authors (like David Brin) have screwed up on this very topic.
Lasers can be used for cooling, by shining a laser on a target carefully set up so that anti-Stokes scattering carries away entropy. The light scattered is quite incoherent, though.
Not really, no. Even if you completely solved the issue of corrosion (which we absolutely haven't), you'd still have to deal with biofouling - anything you leave underwater will rapidly become covered in algae, seaweed and invertebrates. We have antifouling coatings, but a) they're quite toxic, for obvious reasons and b) they need to be regularly renewed.
That would be enough of a problem, but you've also got the cost and difficulty of maintaining underwater infrastructure. It's inherently dangerous, very slow and often made impossible by tidal or weather conditions.
Offshore wind turbines are already much more expensive to build and maintain than onshore, but tidal generators are on another level entirely.
There was a project to build a tidal lagoon in Cardiff [1] that was eventually abandoned, and I don't know about the environmental impact. But it had the merit of being ambitious.
It's more useful for getting from 90%/95% to 100% green energy than from 0% - 90% though, and it's more expensive than natural gas performing the same function so we likely won't see it used in anger for a while.
Where did you get that idea? Hydrogen is extremely hard to work with and really really wants to escape from any containment vessel you put it in. See https://www.sciencedirect.com/science/article/pii/S136403212...
Your article talks about it positively.