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Mimicking Photosynthesis To Split Water
Posted by
kdawson
on Sun Aug 17, 2008 08:19 PM
from the just-add-volts-and-put-it-in-the-sun dept.
from the just-add-volts-and-put-it-in-the-sun dept.
plantsdoitsocanwe writes "An international team of researchers led by Monash University has used chemicals found in plants to replicate a key process in photosynthesis, paving the way to a new approach that uses sunlight to split water into hydrogen and oxygen. The breakthrough could revolutionize the renewable energy industry by making hydrogen — touted as the clean, green fuel of the future — cheaper and easier to produce on a commercial scale." This was a laboratory demonstration only and the researchers say they need to bring up the efficiency.
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Logic, in my Slashdot article? (Score:5, Funny)
This was a laboratory demonstration only and the researchers say they need to bring up the efficiency.
Shame on you, submitter. This is Slashdot, you're supposed to write a sensational story and let the comments tell us why it actually won't work. If you're going to write things that make sense and treat us like adults, you're missing the entire point.
Re: (Score:3, Funny)
Well, there went the logic.
Cambrian Explosion of alternative energy technique (Score:5, Insightful)
We are in a phase similar to the Cambrian Explosion, when all sorts of lifeforms with weird body plans gave it a shot . . . but which were winnowed down to a few by the time things started to crawl on land. Chances are just a few of the many alternative energy techniques being fooled about with will pan out commercially . . . but this is a necessary process.
Now, cue the cranky "Gee, Slashdot posts stories about dramatic advances in solar energy all the time; why doesn't my car run on solar cells yet?" posts.
Re:Cambrian Explosion of alternative energy techni (Score:5, Insightful)
It is easy to get a breakthrough in one criteria if you shaft the other ones.
As an example, you could very well produce hydrogen very efficiently from sunlight without any fancy tech by simply focusing enough sunlight to raise the temperature to 2500 C, at which point water spontaneously separates into hydrogen and oxygen through thermolysis. This would be possible completely without moving parts, no toxic materials, and no new technology.
Problem? It would be much more expensive than making hydrogen from natural gas.
This is why these vapourware stories are so useless. There will be a vast number of ways to convert solar energy into hydrogen or electricity, I could start listing various ways to do it in all kinds of elabourate manners, but it does not mean any of them are good, nor does it mean any one of them is likely to be more efficient than simply using a conventional steam turbine and solar concentrators.
Seriously, what you are attempting to beat is something which, depending on temperature achieved, can have up to 40% conversion efficiency, economies of scale, and uses well tested technology. When you can beat solar thermal then you can start trying to have a go at nuclear or coal, which have a number of other advantages. Simply finding yet another way to convert solar energy into useful work is quite a different thing from solving our energy problems.
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Re:Cambrian Explosion of alternative energy techni (Score:5, Insightful)
This sounds like a bit of a red herring to me.
Are you saying that we should abandon any new idea or technology if, in its infancy, it isn't better than what we already have? I think that would put an end to a great deal of innovation that we could benefit from in the future.
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Re:Cambrian Explosion of alternative energy techni (Score:5, Insightful)
No, I'm merely saying that the fact that you can invent many different ways of doing soemthing is in no way an indication that fundamental problems with it will suddenly vanish. It is not rational to expect solar to suddenly become a silver bullet merely because there is a lot of proposed ways to make solar cells.
Perhaps an analogy is in order. There are LOADS of ways to convert nuclear energy into electricity. There's turbines, direct electrostatic conversion, magnetohydrodynamics, thermoelectric solid state devices, sterling engines, brayton cycles, thermochemical hydrogen production, high temperature electrolysis, etc etc...
Now despite of this you don't see people randomly assuming the price of nuclear is going to drop by a factor of ten within "a few years", because people know that with nuclear, as with solar, and as with coal, the most efficient ( in watts/dollar terms ) generation scheme is to heat one side of a turbine and cool the other one. The other techniques, while interesting from a scientific perspective, are simply inferior in one way or another. They may be inefficient, fragile, may not scale, may involve expensive materials / maintainence etc...
What gets on my nerves with the way these solar technologies are described as major breakthroughs is that they ALWAYS, without exception, are described as something which will revolutionise the energy situation, without as much as a shed of proof that they will even be economical, durable, efficient... They are always along the lines of "Here is yet another way to use solar energy, IF it turns out to be cheap ( which we have no evidence suggesting it will be ) THEN it will change the world.".
That's not a breakthrough, it's speculation of greener grass with no evidence to back it up.
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Re:Cambrian Explosion of alternative energy techni (Score:5, Informative)
It's pretty obvious you are looking for a different breakthrough and it's a certainty you won't find it if you are unwilling to entertain NEW knowledge that MAY be relevant.
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Re: (Score:3, Insightful)
Hmmm, they invented a novel polymer membrane that mimics "a key process in psynth", wasn't it a novel kind of membrane that made fuel cells possible? IANA Industrial Chemist, their contact details are all over the article.
"That's good"
That's the point! It helps 'self-educated' geeks tell the difference between science, psudeo-science, and hype outside their sphere of expertise (or lack therof), OTOH there maybe no hope for those like the troll who
Re:Cambrian Explosion of alternative energy techni (Score:5, Interesting)
No, they're starting with the exact same (expensive) membrane used in fuel cells -- nafion [wikipedia.org]. They've just taken this membrane and added a manganese-based catalyst to it.
I'm amazed that most people never point out the huge, glaring flaw in this notion of setting up big solar electrolysis plants in the sunny desert southwest. Let's ignore the problems of how corrosive the released hydrogen is to your system, which usually makes solar electrolysis have short lifespans. Let's do the same with the free oxygen. And the water. And let's ignore algae growth, which is a problem in most systems that mess with water. And let's ignore hydrogen embrittlement when it comes to raising storage and transportation costs. And let's ignore how huge hydrogen storage tanks have to be due to its very low density, a fact that makes the prior issue even worse. And let's ignore that it has a ridiculously low ignition energy, burns in almost any fuel-air mix, readily evolves deflagrations to detonations, pools under overhangs, enters pipes and follows them to their destinations, burns clear and vigorously, and so on. And let's ignore that leaked hydrogen destroys ozone. And let's ignore that fuel cell stacks are quite inefficient, and that a fuel cell stack strong enough to power a car will cost you hundreds of thousands of dollars. We're talking about *consuming lots of water in a desert* -- enough to power vehicles around the world. What the heck kind of plan is that?
Electricity is our common energy storage and usage medium. Why are we talking about "very low" efficiency, in-the-lab, probably horrible lifespan and very costly hydrogen-solar cells when we could put photovoltaic cells or solar thermal on the same land, get much better effiency from a much cheaper system, transmit the electricity efficiently (92.8% average in the US), rectify it efficiently (~93% charger efficiency), charge/discharge it efficiencly (96%-99.9% in li-ion), and convert that to kinetic energy efficiently (85-90% typical electric motor efficiency in a normal drivecycle), in a vehicle that uses batteries that cost *literally* an order of magnitude less than said fuel cells, can level-3 charge in as little as 5-15 minutes (depending on the type), and have longer lifespans to boot?
The "hydrogen economy" is just a silly concept; nothing about it makes sense in comparison to an EV economy with modern automotive li-ion batteries.
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Re:Cambrian Explosion of alternative energy techni (Score:4, Funny)
Good luck raising cash for investment while being extremely sober in your analysis!
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Re:Cambrian Explosion of alternative energy techni (Score:5, Insightful)
How about we let them work out the bugs before posting to slashdot?
Two reasons:
1) The possibility is interesting even if the probability is currently uncertain. ("Of what use is a baby?")
2) Even if it was obvious that the process couldn't be scaled up in any economically feasible manner, it's still interesting to some people on a basic science level.
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Re:Cambrian Explosion of alternative energy techni (Score:5, Funny)
That clearly depends on its tensile strength.
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Re:Cambrian Explosion of alternative energy techni (Score:4, Informative)
What bugs? Did they NOT mimic photosynthisis? - Did you find a methodology error in their paper? Do you know of published contra-evidence?
"Seems a lot of the stories get posted to get into "the media" without having the required science/adverse analysis/hostile counterpoint process done."
The science has been published in a respected peer-reviewed journal and comes from two leading scientific institutions down here in Oz. Did you have some other 'process' in mind?
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Re:Cambrian Explosion of alternative energy techni (Score:5, Insightful)
This wasn't an engineering design, it was pure research. "Can we do this?"
The answer is yes. Now the engineers can try to find a way to do it within constraints, whether environmental, economical or both.
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Re:Cambrian Explosion of alternative energy techni (Score:4, Insightful)
The sun's surface temperature is more than 5000 C , so the laws of thermodynamics certainly don't prevent you from reaching 2500 C using the light emitted from it.
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Re: (Score:3, Informative)
Another use for this technology would be a sort of energy pack that goes on the roof. A water line goes in, hydrogen comes out and is stored in a fuel cell which powers the house.
Fuel cells don't store hydrogen - they use it as fuel. Hydrogen storage is a can of worms entirely separate from the fuel cell that has its own challenges.
Problem is what to do with all the waste oxygen.
Um, what problem ? You either store it, too, and use it when your fuel cell generates electricity, or you just release it into t
Re: (Score:3, Interesting)
I agree with you. How about these guys?
http://web.mit.edu/chemistry/dgn/www/research/e_conversion.html [mit.edu]
They bounced into the news a few weeks ago.
Re:Cambrian Explosion of alternative energy techni (Score:5, Interesting)
Actually, your answer to why your car doesn't run on solar yet is rather simple. Because we haven't needed solar power to win a war yet. Nuclear got everything it needed to get off the ground, working, demonstrated, and dropped. It was needed to fight a war. Radio, space ships, etc? Same things. The US Military is just starting to come to the conclusion that half their vehicles exist solely to deliver fuel and supplies to the other half(the fighting half) and that there is a huge risk in running tankers full of Diesel and gas to forward areas, as they become very easy targets. Destroy the supply lines, and those 70Ton M1A tanks become very large, immobile targets. Add to that, the skyrocketing cost of fuel the military has to buy. (not to mention, the huge costs of keeping 50% of your peopled tied up in support roles).
THat is why the military is starting to look at things like solar, small nuclear plants, etc. They are looking at hybrid vehicles that work like a train, the whole powertrain is electric, powered by a generator. Some of these vehicles are pretty cool, they could sit there and idle at the forward CP, and you just plug all your radios and equipment into the truck. No need to lug a generator with you.
I have a feeling things are going to improve quite quickly over the next few years. Nothing improves technology like fat government contracts!
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Re:Cambrian Explosion of alternative energy techni (Score:5, Informative)
Gas as in gasoline is rarer the hen's teeth in the US Army, the only place I remember it being used is in the mess for running stoves, ovens, and water heaters; and I retired back in 1985. I wouldn't be surprised if there weren't new stoves that ran on JP4, military jet fuel and or water-clear kerosene by now. Gasoline is just nasty dangerously flamable stuff especially around bombs and bullets.
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Re:Cambrian Explosion of alternative energy techni (Score:5, Interesting)
In the late 1980s a mountaineering stove came out that could run on those fuels - the whisperlight international. Admittedly one of the first of them was hurled into a crevasse on Mt Erebus in Antarctica by a critic. However the later ones were better and there have been lot of other multi-fuel stoves since then.
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Re:Cambrian Explosion of alternative energy techni (Score:4, Informative)
We still use JP for our mil vehicles, but we use a lot of NTVs (non tactical vehicles) now which are from I have seen over the last few years a fairly even mixture of gas and diesel.
The stoves, heaters, and yes, we have a/c now in even the training tents, all run off electricity which comes from generators that are fueled by something brought in by contracted companies. Diesel? Gas? I don't know because I haven't seen the paperwork for the contracts. It all depends on who we contract out for the generators and what kind of generators they bring in for us.
I think that was the biggest change in Army ideology over the last 20 years or so... they've shifted a huge portion of the green suiters' work onto civvie companies and contractors.
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Re:Cambrian Explosion of alternative energy techni (Score:5, Insightful)
You know what a joke during the early times of the Newcomen steam engine was? You need three mines to run a steam engine. One mine where you apply it, one coal mine to fire it and one silver mine to pay for it.
Know what? It changed.
If people would've taken the position you have now and ignore Newcomen's development, the industrial revolution would not have happened, at least not in the way we know it. Yes, the steam engine was horribly inefficient and in most cases uneconomical until Watt made his improvements. After that, though... well, you know history I'm sure.
What we have here is not even yet the equivalent of a Newcomen machine. This has a long, long way to go, give it a decade and good funding and this can go a long way.
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Re:Cambrian Explosion of alternative energy techni (Score:3, Interesting)
That is very much how the motor car industry started out - you had well over 3000 startup companies all across North America and Europe, experimenting with the combustion engine, and inventing different improvements (carburettor, cooling fan, 2-stroke, 4-stroke and 8-stroke engines). Eventually, over time they merged together to form larger companies and eventually forming a handful of corporations.
How many solar panels would they need on a car to have a completedly closed system (solar panels to generate
Not new (Score:5, Informative)
This was a laboratory demonstration only and the researchers say they need to bring up the efficiency.
There have been numerous such laboratory demonstrations on different ways to produce hydrogen easily. But the attempts to bring up efficiency are just what failed.
Re: (Score:3, Informative)
Re:Not new (Score:5, Informative)
I don't think so, although I initially thought the same thing.
The MIT process (from July 31 /.):
"..catalyst is made from cobalt, phosphate and an electrode that produces oxygen from water by using 90 percent less electricity than current methods, which use the costly metal platinum."
The Monash team (todays /.):
"..using just sunlight, an electrical potential of 1.2 volts and the very chemical that nature has selected for this purpose". The chemical seems to be "a form of manganese".
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need to bring down cost too I bet. (Score:3, Interesting)
Why not just put in a solar panel? 3x the efficiency of the best plants and none of those messy chemicals, plus much better applicability.
Re: (Score:3, Informative)
Because normal electrolysis of water isn't very efficient at producing hydrogen.
This is a system for generating Hydrogen which can then be stored and used as a fuel either in an internal combustion way or with a fuel cell.
Solar panels are a way to generate electricity which then must be stored and used. Storage of electricity is generally a pretty big inefficiency, and solar panels only really work when the sun is out, so they necessitate storage or supplemental energy generation systems.
Re: (Score:3, Interesting)
I've got sunlight and I want hydrogen. Whoops, the inefficiency in the solar cell is still part of the process.
Re:none of those messy chemicals? (Score:5, Funny)
You don't win friends with salad.
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Not as good as advertised. (Score:3, Informative)
Re:Not as good as advertised/ Fixed URL (Score:4, Informative)
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Voltage != energy (Score:4, Interesting)
If you had to apply a potential of 1.2V to catalyse the reaction then that is OK so long as the process is chomping very little current and is instead getting the bulk of the energy from the light.
Of course if it is using a lot of electrical energy and just a small amount of light energy then it isn't really much improvement over electrolysis.
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plants can split molecules? (Score:4, Funny)
they must be working up to the atom. this means war! bomb the crap out of those planty bastards.
Photosynthesis is Inefficient (Score:5, Interesting)
Photosynthesis has a maximum theoretical efficiency [fao.org] of about 11% from sunlight into energy stored in biomass (eg. the plant). But in the wild, it's only 3-6% efficient.
Familiar PV cells already get 15-25% efficiency; experimental concentration cells get over 45%. And the PV outputs electric current, not just biomass to burn inefficiently.
Those cells cost a lot more energy to make than plants do, but they last over 30 years, while most plants don't.
I'm not so sure that mimicking photosynthesis is such a great way to go.
Carbs (Score:3, Interesting)
FTFA: This process of "oxidizing" water generates protons and electrons, which can be converted into hydrogen gas instead of carbohydrates as in plants.
Well, hydrogen is nice and all, but I can see an equally compelling reason to work on generating carbohydrates (preferably edible) with this method instead. Especially in places with no plants where having a food source would be awesome - places like long-range manned space flights, as-yet-un-terraformed planets like Mars, and god-forsaken hell-holes like the middle east and the Sahara.
"Soylent green is...well, it's sunlight and carbon dioxide...and 1.2 volts"
Re:I'll believe it when I see it (Score:5, Insightful)
Let's give them some credit at least. They've managed a break through in science and just because it's not perfected yet, you feel the need to disregard it completely? They obviously know it needs more work, they admitted so in TFA.
Give 'em a break man.
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Re:I'll believe it when I see it (Score:5, Insightful)
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Re:I'll believe it when I see it (Score:5, Insightful)
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Re:I'll believe it when I see it (Score:4, Insightful)
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Re:I'll believe it when I see it (Score:5, Interesting)
Nah, after GUT [wikipedia.org] there's still TOE [wikipedia.org] to shoot for. And after TOE we can really start developing theories about parallel universes with twisted GUTs and ticklish TOEs. There's always more work.
And if all else fails, there's always the "soft" humanist sciences. There's as much work there as you can make up.
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Re:I'll believe it when I see it (Score:4, Funny)
porn.
everything's been done in porn...
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Re:I'll believe it when I see it (Score:5, Funny)
I think this is awesome news personally.
Next stop: Cold fusion! :)
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Re:I'll believe it when I see it (Score:5, Insightful)
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Re:I'll believe it when I see it (Score:5, Interesting)
How many plants move around? How many animals use photosynthesis to get the energy to move around? What is the ratio of plannts / animals in the world?
If evolution is a teacher it is telling us that sunlight is so diffuse that you need vast areas of collectors to power even a small number of things that move about. Unfortunately, we want to move a lot of stuff using minimal impact on our surroundings, so we want something less diffuse in nature.
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Re:I'll believe it when I see it (Score:5, Insightful)
How many animals use photosynthesis to get the energy to move around?
Ultimately, all of them.
What is the ratio of plants / animals in the world?
It is extremely high, necessarily.
Compact energy sources are finite and have quite significant impact on our surroundings. In order to move the most amount of stuff possible, humans must learn to disintermediate plants.
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Re:I'll believe it when I see it (Score:5, Insightful)
So indirectly, cows are solar-powered, aren't they ?
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Re:I'll believe it when I see it (Score:4, Insightful)
30 years?
I think that is a bit long. If you think tech takes 30 years from initial lab stages to general practice I think you've missed some history classes. Try reading up on the Manhattan Project and Computers sometime.
While it is true that development can take decades it often goes much quicker.
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Re: (Score:3, Insightful)
There is quite some variation. We are still waiting for the fusion reactors. In regards to the computers, it all depends on what you mean by initial lab stages and general practice. If you consider Babbage's difference engine (proposed 1822) as an initial lab stage and the availability of affordable computers for the masses (1970 sometime), the computers took 150 years.
Re:Water Shortage (Score:4, Interesting)
It's better than that. If you take non-potable water and produce pure hydrogen, then when you burn the hydrogen you get potable water. One popular demonstration of the "greenness" of hydrogen cars is to catch the water dripping from the tailpipe in a glass and drink it. I'd only try that if your hydrogen is pure, of course. ;-)
I still favor electric vehicles over hydrogen, however, at least for the next few decades. Electrics have only one significant problem stopping mass deployment - energy density of batteries. Hydrogen has many - the cost of producing hydrogen, the cost of compressing or liquefying the hydrogen, the impermanence of liquid hydrogen ("venting"), the safety concerns of carrying around enough hydrogen to power a car without a "Hindenburg effect", and the cost of a new infrastructure to transport megatons of hydrogen to fueling stations scattered across your country.
Or maybe that's just my EE degree coming through.
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