5 ms·
The power generation potential given is in units which make it almost useless. A kWh is a unit of energy, converted into a frame of reference more useful than t
by leoedin 7y ago
The power generation potential given is in units which make it almost useless. A kWh is a unit of energy, converted into a frame of reference more useful than the joule. Saying that a device can generate 2 kWh doesn't really tell you much - it could generate that in 10 seconds (good) or 10 years (bad).
I think the quoted figure was meant to be in kW - a unit of power, which is a much more useful piece of information. I looked at the original paper (here: https://arxiv.org/pdf/1907.13170.pdf https://arxiv.org/pdf/1907.13170.pdf) but couldn't find any reference to the 2kWh quoted from the researchers.
If the suggestion is correct, and a 10mx10m panel can generate 2kW, then there's some really interesting potential applications. History has shown that the path towards robust technology is normally by making things solid state - vacuum tubes to transistors, solar collectors to solar panels, even helicopters to drones all benefited from a huge decrease in mechanical complexity.
- andy_ppp 7y agoNot to mention salt water corrodes almost everything that comes into contact with it...
- Zenst 7y agoOne aspect about salt water corrosion/rust is that it pulls off the oxygen and releases the hydrogen, albeit at a very low level, but always seems like some way to produce hydrogen without adding any power. Quick dig shows this is one area of research that is ongoing.
- leoedin 7y agoBut then you've basically got a machine which turns iron into iron oxide and hydrogen, which you'll then have to put loads of energy back into to return to raw iron again. At best its an energy storage method. I can't imagine it's got a very good round trip efficiency though.
- thaumaturgy 7y agoIt might be a nice add-on for desal plants, which already have plenty of waste saltwater getting pumped around. Someday.
- imglorp 7y agoI think that's the key right there: motion of the water. There's no free lunch here; it's not a battery. Maybe a good application would be throwing the whole rig into the surf, or a salty tidal stream, where you get the induced current from lunar power.
- ihaveajob 7y agoYour comment made me go on a total tangent considering whether the Moon with eventually fall on us if we harvest enough tidal energy due to gravitational drag. But interestingly enough, the opposite is true, tidal drag is actually moving the moon further away from us, and slowing down the Earth's spinning.
- Gracana 7y agoThat didn't make sense to me, so I looked it up and found there's a good wikipedia article about it (which you probably read as well.) It's too much for me to explain poorly in an HN comment, so I'll just link it for anyone who's also scratching their head: https://en.wikipedia.org/wiki/Tidal_acceleration#Effects_of_Moon's_gravity https://en.wikipedia.org/wiki/Tidal_acceleration#Effects_of_...
- ihaveajob 7y agoThe key point to me was that since earth is spinning about 28 times faster than the moon rotates around us, the drag force equalizes the frequencies by making earth spin slower, and the moon rotate faster, thus further away from us. Eventually they'd be in equilibrium, spinning in lockstep.