March 5, 2010 weblog
Catalyst could power homes on a bottle of water, produce hydrogen on-site (w/ Video)
(PhysOrg.com) -- With one bottle of drinking water and four hours of sunlight, MIT chemist Dan Nocera claims that he can produce 30 KWh of electricity, which is enough to power an entire household in the developing world. With about three gallons of river water, he could satisfy the daily energy needs of a large American home. The key to these claims is a new, affordable catalyst that uses solar electricity to split water and generate hydrogen.
Using the electricity generated from a 30-square-meter photovoltaic array, Nocera’s cobalt-phosphate catalyst converts water and carbon dioxide into hydrogen and oxygen. The process is similar to organic photosynthesis, except that in nature, plants create energy in the form of sugars instead of hydrogen.
The hydrogen produced through artificial photosynthesis can be stored in a tank and later used to produce electricity by being recombined with oxygen in a fuel cell, even when the sun isn’t shining. Alternatively, the hydrogen can be converted into a liquid fuel.
"Almost all the solar energy is stored in water splitting," Nocera said at the first-ever ARPA-E (Advanced Research Projects Agency-Energy) conference last Tuesday. "We emulated photosynthesis for large-scale storage of solar energy."
With his start-up company, Sun Catalytix, Nocera hopes to make the system affordable enough to allow individual homes to generate their own fuel and electricity on-site. By distributing hydrogen production in this way, the new method could potentially solve the problem of hydrogen transportation.
“If I could store the sun in terms of a fuel, then at night when the sun goes down I can use the sun, effectively,” Nocera said in a company video. “What we’ve done is that we’ve made sunlight available 24 hours a day, seven days a week.”
In January, Sun Catalytix was awarded $4 million in government funding through the new ARPA-E agency. Modeled after DARPA, ARPA-E was formed to promote the development of advanced energy technologies - in this case, “direct solar fuels,” or “electrofuels.” Nocera explained that Sun Catalytix is using the financial support to take its prototype to the next level.
“Where Sun Catalytix is headed is that your house would become its own power station and gas station,” he said in the video. “All of a sudden, you don’t need any more energy from anybody else because you’re using the sun at your house.”
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User comments
How much of the total energy available in the H2 does it take to store (compress) the hydrogen in the "tank"?
Does the catalyst reduce the energy needed to split the H2O to H2 + O?
the big question, is it just another laboratory curiosity or commercially viable? Nothing clarifying any of the questions on the website, nor in the 4 referenced paper abstracts.
IE IS IT CHEAPER. Efficiency of dollars is what matters to me.
30kw*4=120kwh
120kwh/30kwh = 25% efficiency for hydrogen generation.
And a lot of water might be generated from the electric generation.
Peak solar radiance is 1KW per square meter with the sun directly overhead. 30 Sq meters would be 30 KW. The article says they need 4 hours to produce 30KWh of energy with a 30 Sq meter array. That's 25% conversion efficiency.
Just a thought:
Carbon dioxide being the main "pillar" of the AGW crowd. Water vapour being an even much stronger greenhouse gas. The produced oxygen could be contained aswell for later use (mainly for the reverse process).
When using the hydrogen to generate energy afterwards, the by-products of the process (CO2,water vapour) could be contained aswell. If this was used on a large enough scale and the CO2 stored + water vapour condensed, it could (to a certain level) directly compensate for the human-produced carbon dioxide.
This looks far too good to be true..
Hoax? Or hidden advertisement for an extended arm of the AGW machinery? Or maybe true? Time will tell..
Wether it will be viable or not depends on what it takes to make the cobalt-phosphate catalyst and what the waste products of the used process are, after all..
In the reverse process using a fuel cell and hydrogen as the energy source water is created as the byproduct. No C02 produced. So it truly would be clean.
Yes. Most of the time it is much less than 1KW per square meter (weather and the 1KW figure is only reached at midday).
Also this supposes that we have solar cells which are 100% efficient (which we don't - far from it). So the 30 sq meter figure goes up accordingly.
Add to that that most people in the cities do not have 30 sq meters of rooftop space (per family) but much less than that (think how much roof space a family has in a skyrise)
That said: If the catalyst is stable over a long period of time then this could be good for making largish solar power plants that store excess energy in hydrogen (or even help to switch over to hydrogen economy altogether).
Unless this MIT feller has rewritten the 2nd law of Thermodynamics . . .
Use the solarpower??
you would need to produce the catalist, containers...
But I don't see any details about its yield, catalyst stability and basic economical numbers (price tag of energy produced in such way).
Catalysts, by definition, don't get consumed in the process. You get some catalyst, and keep using it, and using it and using it. As such, its cost is just factored into the cost of your solar rig.
Where's the Carbon coming from? Combusting Hydrogen with Oxygen creates water and energy, no magical alchemy is taking place to produce Carbon.
That's not quite true. While the catalist does not get consumed in the reaction the catalyst usually degrades over time. If it is expensive and needs to be replaced ever so often then that might be a drawback
(Conversely fuel cells recombine H2 and O2 without the fuel cell membrane being worn down in the reaction, but the membrane does wear out over time. This is something that still needs to be figured out)
As for the article: making hydrogen and oxygen frome power and water is not exactly new. Everybody should have seen this in school in elementary chemistry class. The article/video doesn't really give any info on what is supposed to be new here.
And no: The process described is NOT similar to photosynthesis. Photosynthesis in plants uses CO2 and water to create sugars (at a dismal energy efficiency of about 3%), not water and energy to create hydrogen.
Bloom Box runs on Natural gas. They're incompatible technologies.
Richard Feynman
Sounds a lot like public relations to me! Are they taking into account things like the availability of cobalt and phosphates and the costs associated with their extraction, processing, transport etc... Didn't think so.
bloom boxes will quite happily catalyze pure H2.
Id be interested to know how you propose to store this hydrogen without needing some sort of cooler compressor and fail safe system, remember, hydrogen is combustible in as low as 4% concentration.
that wasn't supposed to sound so negative...
The risk of explosions is substantial.
The electrosynthesis of hydrogen in utility scale
solar plants might be feasible.
Yeah- a little sloppy there with the terminology.
Hopefully everyone ignored that, and looked for my point: Either much greater efficiency, or much lower cost required, realistically, to implement this tech. Ideal solution would be both, n'est pas?
The objections to the dangers of hydrogen would sound a lot less like denier wanking if lead acid batteries didn't explode, old ladies' houses didn't explode, furnaces didn't explode, cars didn't burn, dryer lint filters, extension cords under your bedpost. Get the drift?
Alcohol abuse, anyone? Drunk driving?
Let's talk technology, not politics. It's such a dead end.
Why not? If the is leak small then the gas will just move upwards (not pool on the ground like gasoline since it is lighter than air). If your basement is designed to let some air out at the apex then that H2 will simply escape into the atmosphere long before you will get to the 2% mark.
Also note that H2 'explosions' are quite tame. The energy per volume released at one atmosphere pressure (which is what escaped H2 would be at) is dismal. You could fill a whole room at that pressure and ignite it without much more than a noisy 'whoop' and no damage whatsoever to your house (doesn't anyone remember this experiment from chemistry class?)
If ignited the flame does not blow back into the leaky cannister (because it is pressurized). It simply burns off without exploding.
http://www.evworl...ryid=482
(for the home owners: as with oil reservoirs you probably would not have that reservoir in your basement but buried in your yard. So a flare off or a leak isn't really a problem. )
At a huge loss in efficiency. Oxidizer cells are dependent on multistage reactions. The fewer stages, the less efficient the device becomes.
If not, then we could solve our energy and sea-level-rise problems simultaneously by sticking a massive input tube into the ocean.
This is an extraordinary misleading statement. In your chemistry class you made sure your hydrogen was pure and had no air left in the mix. Hydrogen/oxigen mix is explosive over extremely wide range of concentrations (4-75%):http://www.engine...23.html. Gasoline is only 4.4-7.6%.
Filling your room with hydrogen will create an extremely explosive mix which is sure to fold your house as a house of cards.
Some demonstrations of clean H2 burning are missing the fact that leaking H2 is likely to accumulate and mix with air rather than by burned right on the outlet.
Hydrogen releases 241.8 kJ of energy per mol
Methane is more than three times that (891 kJ/mol)
Gasoline vapors have about 22 times (!) the energy content of hydrogen vapors.
Since we are talking about what would happen if a hydrogen pipe leaked the "per mol" (which is 22.4 liters for any ideal gas) is relevant since we are then dealing not with a pressurized gas anymore but with one at one atmosphere pressure.
Filling a room with hydrogen and letting it explode is NOT going to fold your house
Here's a video of a balloon full of the stuff exploding (i.e. already somewhat preesurized which we wouldn't even have in our case). It doesn't explode with much force.
http://www.youtub...YhJ2jHWw
Agreeing with jshloram's calculations above, overall they are talking a 25% efficiency. Since you can't get something from nothing, that means that the solar panels must be significantly greater than 25% efficiency.
So how is this better than charging batteries from a PV array? It sounds worse than something that's already not very cost effective (yet). Hydrogen is not the most friendly energy storage medium from the point of view of implementation cost or safety.
As much as we are being programmed to dislike them, hydro-carbons have a lot going for them.
now contrast this with a gas baloon exploding
http://www.youtub...RK4JfnEA
see the difference?
Yes. Just an incremental improvement at that, but certainly worthy of exploration and further study: Catalytic electrolysis of water into Hydrogen and Oxygen is not new, certainly, but the use of chemist Dan Nocera's new catalyst may be.
Yes, the originating source of power, Solar photovoltaic cells, is nothing new nor improved, and really just clouds the real science in this article, thus my 2 start rating for the overall story, but I would give much higher marks for the "red meat".
From the previous posters, I would assume that the technology in this article is a hoax. ARPA-E was duped.
By the way, 30 square meters is 18 feet by 18 feet.
I believe a lot of people on the planet have this much space available.
http://www.powerm...857.html
The gray box at the bottom, however, should clear up any false sense of dread peop�le have towards hydrogen. Natural gas/gasoline are _much_ more dangerous and we have no compunction about having them in our homes/cars.
No, no. Someone suggested coupling the above tech with a Bloom Box. The BB is just an oxidizer cell (a super efficient one at that), and as such would yield a paltry amount of energy release out of an 2H2 O2 -> 2H2O reaction.
The abstracts to the articles on the SunCatalytix webpage made mention of this catalyst producing an H2 equivalent from a proton accepting hydrogen phosphate rather than actually evolving H2 gas.
Is CO2 somehow involved in the production of H2 from this H2 equivalent? I don't have journal subscriptions available to me like I did when I was a student so if anyone could clarify I'd appreciate it.
Please explain how H20 and CO2 can be converted into H2 and O2. The author needs a lesson in chemistry unless the carbon breaks down into hydrogen through fission or through fission combines with hydrogen atoms to form oxygen. Maybe it is the fission or fusion that provided the energy.
This the third article on physorg that I have looked at today that indicates the authors grasp of science is negligible. Does anyone who has passed high school physics or chemistry look at this "stuff" before it is posted?
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