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MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

wired.co.uk

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Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#51

Post by erikpukinskis »

johnny22 wrote: post #30
photophotoplasm wrote: post #26

> MIT's artificial leaf is ten times more efficient than the real thing This doesn't surprise me, to be honest. Organisms have evolved to be fit enough to survive, and efficiency above a certain level might not affect an organisms fitness (or might even affect it negatively).

yes, if the plant sucks up too much power it might get too hot and lose too much of the often more scarce water. or something like that anyways..

Photosynthesis stops above a certain temperature due to quantum effects anyway, so there's a natural governor. And I assume plants' vascular system also does some cooling.

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#52

Post by deadbadger »

prawn wrote: post #13
mhb wrote: post #12

Earlier quoted context omitted.

But 45 hours and one day aren't that different.

Well, different but I agree, not different enough to call one highly unstable and the other stable.

Certainly not when you're trying to judge energy payback horizons for a device incorporating silicon, nickel and cobalt, all of which come with significant costs of production. What if the degradation isn't linear, as seems very likely? Obviously it's a significant improvement, but 45 hours' operation tells us virtually nothing about the device's likely practicality.

The real problem here is that, as usual, we're forced to speculate about what should be straightforward facts, because the story in the OP is based on a dumbed-down press release relating to a talk we can't see, describing research we can't freely access (http://web.mit.edu/chemistry/dgn/www/pubs/publications_2011....), and as a result contains almost no actual information. So it's grandiose claims "we could power the third world!" without any means of assessing whether they're even plausible.

None of this is to say the new cell isn't really interesting, of course. But it's just so typical of science churnalism.

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#53

Post by DannoHung »

ars wrote: post #48
berntb wrote: post #20

Earlier quoted context omitted.

>>Solar panels are already good enough that they are used in developed countries such as USA and UK. Are they perfect? No, they cost too much, and they don't generate enough electricity, but they are used none-the-less. Does no one follow energy news, except for oil prices and the Polywell project?! :-) Many estimates talk about soon reaching "grid parity" in large parts of the world. If this leaf isn't good enough,…

BTW one reason that Grid Parity is a moving target is that one of the input costs to making solar power is energy. When energy (hydrocarbon fuel) becomes more expensive, instead of making solar power cheaper in comparison, it has no real effect. Instead, regular power becomes more expensive, which makes building solar power also more expensive, and the net result is a wash.

That seems weird. That would imply that the lifetime energy capture of a solar panel is roughly equivalent to the creation and installation energy cost.

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#54

Post by MichaelApproved »

Natsu wrote: post #42
bad_user wrote: post #38

Provide every house on the planet with an artificial leaf and we could satisfy our 14 terrawatt need with just one gallon of water a day. One gallon of water a day, in case we are talking about freshwater, is waaaay to much. In case you haven't noticed, there are regions in this world with a freshwater deficiency (precisely those third world countries which would benefit from something like this), and one gallon of w…

> One gallon of water a day, in case we are talking about freshwater, is waaaay to much. I wonder if there's any reason why it couldn't use saltwater? I guess it's possible that the salts would cause trouble or clog things up, but...

Salt water tends to corrode things or the salt builds up and clogs things (See the issues Japan is having putting salt water into their reactors).

Also, depending on the materials used, I believe it also creates chlorine gas as a byproduct.

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#55

Post by luckyfish »

corin_ wrote: post #2

If this is as good as it seems to be, why is the focus purely on the third world? Unless I'm missing something, this could bring cheap and extremely environmentally friendly energy to developed countries too. If it's purely a case of "they need this more than we do", why not either just license out the technology to companies who can use it, or develop it themselves for developed countries. Either way, they could tak…

A better use for this technology in the west would probably be inside of a powerplant, because generating power from hydrogen is probably cheaper in a large scale power plant than using a fuel cell.

My guess it's pretty hard to deploy new technologies inside of powerplants. It takes years of testing, larger sums of money, and very long sales cycles.

So it makes more sense to develop a grid-less version for the developing world, that would serve both as a commercial product and as a proof of concept for the technology, and would take much less time and money to deploy.

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#56

Post by dctoedt »

Is "photosynthesis"[1] the correct term? Seems to me that "photolysis"[2] would be closer (although readers would get the gist of the former more quickly).

[1] http://en.wikipedia.org/wiki/Photosynthesis

[2] http://en.wikipedia.org/wiki/Photodissociation

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#58

Post by mryall »

tesseract wrote: post #21
corin_ wrote: post #6

Earlier quoted context omitted.

Solar panels are already good enough that they are used in developed countries such as USA and UK. Are they perfect? No, they cost too much, and they don't generate enough electricity, but they are used none-the-less. By the sound of it, this new creation would be more efficient, either in price, electricity generation, or both, than traditional solar panels - if that wasn't the case, why on earth would any project u…

I don't see, in the linked article, a comparison of the efficiency of this device to that of existing solar panels (which are quite a bit more efficient than natural leaves).

> [solar panels] are quite a bit more efficient than natural leaves ...

Got a citation for that? I'd be interested to learn more.

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#59

Post by antihero »

jbri wrote: post #4
corin_ wrote: post #2

If this is as good as it seems to be, why is the focus purely on the third world? Unless I'm missing something, this could bring cheap and extremely environmentally friendly energy to developed countries too. If it's purely a case of "they need this more than we do", why not either just license out the technology to companies who can use it, or develop it themselves for developed countries. Either way, they could tak…

Earth receives about 1.3 to 1.4 kW per square meter from the sun (and that's before the atmosphere absorbs and reflects a huge chunk of that) - which is effectively an upper bound on the energy that can be produced by any solar power source. A playing-card sized device is going to take more than a day to produce a day's worth of electricity for a current developed-world lifestyle, even if it were 100% efficient.

What if we covered our houses with them? Instantly I'm dreaming of lush, green cities, covered with the stuff :)

Re: MIT's artificial leaf is ten times more efficient than the real thing (Wired UK)

#60

Post by rbanffy »

Is it my impression or this device produces energy and water? It apparently works with seawater and, since its exhaust is hydrogen and oxygen that will be recombined in a fuel cell, the end result will be solar power and desalinated water.

I believe this alone is almost more interesting than the power output.

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