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from the seawater-is-more-than-just-salty-water dept.
There are many ways to generate electricity—batteries, solar panels, wind turbines, and hydroelectric dams, to name a few examples... and now, there's rust.
New research conducted by scientists at Caltech and Northwestern University shows that thin films of rust—iron oxide—can generate electricity when saltwater flows over them. These films represent an entirely new way of generating electricity and could be used to develop new forms of sustainable power production.
Interactions between metal compounds and saltwater often generate electricity, but this is usually the result of a chemical reaction in which one or more compounds are converted to new compounds. Reactions like these are what is at work inside batteries.
In contrast, the phenomenon discovered by Tom Miller, Caltech professor of chemistry, and Franz Geiger, Dow Professor of Chemistry at Northwestern, does not involve chemical reactions, but rather converts the kinetic energy of flowing saltwater into electricity.
https://phys.org/news/2019-07-ultra-thin-layers-rust-electricity.html
More information: Mavis D. Boamah et al. Energy conversion via metal nanolayers, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1906601116
(Score: 2) by Immerman on Friday August 02 2019, @03:05AM (1 child)
I'm not paying to skim the paper, and the top several results from Google all have the exact same quote:
>"For perspective, plates having an area of 10 square meters each would generate a few kilowatts per hour -- enough for a standard U.S. home" Miller said.
Heck, they might all be republishing the exact same press release - I just searched for "watts"
I'm confident it was a units flub. Though I've heard that in the power industry (and perhaps researchers?), where "kWh" is the "normal" unit to be discussing, and is often shortened to just "kW" when speaking, in which case "kW/h" would in fact be the correct way to converse about instantaneous power - doubly so since it's pretty much a nonsense unit so that it won't confuse anyone (except outsiders, but how often do you talk to them about your work?)
At any rate, lets get to the meat of the claim: assume that Miller at least knows what they're talking about, and that "enough for a standard U.S. home" is correct. The average U.S. home consumes about 10,000kWh per year, or an average of a bit over 1 kW-hour per hour. Of course peak load will be a few times higher than that. So "a few kW hours per hour" would in fact provide for the average U.S. home, with a generous window for individual variability (or leaving out the batteries), and is almost certainly what he meant actually.
So this technology could supposedly produce a few hundred watts per square meter, which would put it roughly on par with solar panels in terms of peak generating potential per unit area. And I would presume this could be "stacked" in all sorts of interesting ways - how much surface area is in a car's radiator? If it could be made cheaply enough this might be a huge boon to seaside communities. Of course there is the question of how it actually stacks up to other forms of wave and tidal power. The lack of moving parts would seem to be a huge boon, but that's an awful lot of delicate surface area to keep clean and undamaged
(Score: 2) by hendrikboom on Friday August 02 2019, @11:52AM
Love the unit! It's probably what the original article needed in the first place!