Here's the paper behind the PR announcement. Some interesting bits but I wasnt able to figure out anything about the possible cost to operate the device https://www.nature.com/articles/s44221-023-00139-9
The principle of this type of device has been around usually as a thought experiment for years (simple electrolysis or water evap from solar power).
Sadly they have not been efficient.
What they appear to have innovated on (skimmed summary only) is using newer tech to add a carbon mesh for filtration of dirt and raise the device to protect it, and allowed more sunlight through the panel to evaporate the water more efficiently.
By themselves some of these things may already be patented or done in academia, but this looks like the first time I've seen them all combined in a single device.
Nb. another similar device is a pool cleaner using solar to ionize the water, useful in small volumes, a few of those plus these devices may help clean small drinking pools.
>...which produces green fuel with a solar-to-hydrogen efficiency of 0.13 ± 0.03% and 0.95 kg m−2 h−1 of water vapour as the feed for the PC and collectable purified water. This integrated system maintains operational stability in seawater and other aqueous waste streams for over 154 h due to the isolation of the PC from contaminants in the liquid feedstock.
So, wildly inefficient, but if the device is cheap enough to produce, could still be worthwhile where there are no other options. I know there is some interest in floating solar panels, which would probably be significantly more efficient (can centralize the hydrogen/H2O production at a large scale facility), but that struck me as introducing a host of engineering problems vs finding some unused land.
Exactly. It's manufacturing + installation + maintenance + infrastructure cost that define what this costs. I'm guessing these would need quite a bit of maintenance and attention. Things get dirty, hoses get blocked, etc. And of course reservoirs for fuel and clean water fill up. You are not going to put these in the middle of the ocean probably.
This looks like it is designed for small scale usage close to where people live.
> The device ... could be useful in resource-limited or off-grid environments, since it works with any open water source and does not require any outside power.
Or in a country where the gov privatised the water companies and then these companies started dumping sewage in all the waterways instead of doing there jobs, like in England.
If this is inefficient, what are you comparing to? What is the best way to purify water or produce hydrogen with solar energy? Is there a good way? Certainly producing electricity first can't be the most affordable way?
So now we are going to deploy thousands of mostly metal and plastic devices into contaminated seas to produce fuel and water, which will in turn just be used to make humanity even more efficient and expanding....
What I hate about this device is that it doesn't give anything back to the polluted sea. It doesn't try and clean anything. It just takes...takes away from an already wounded wild environment fuel and water, and leaves it just as polluted as before.
That's how we are -- always taking from the earth without giving anything back. We should have the philosophy that whatever we take, we should try and give back at the same time. So, if we remove 1 cup of water, we should try and remove 1 cup of toxic substances too or construct some natural, protected area in return.
How does your stewardship calculation deal with energy poor regions that burn pretty much anything, regardless of associated long term health risks? Or more generously, is no benefit realized if solar generated hydrogen replaces some useful crude oil derivative?
If being a good steward is your priority (and more power to you if so), then this is probably the wrong post to get maudlin over. I mean, how else will you power an autonomous ocean plastic-picker-upper? :)
