http://www.physorg.com/news85074285.html
A look at why a hydrogen economy might not be the answer to our future energy needs.
epic
A look at why a hydrogen economy might not be the answer to our future energy needs.
epic
Hydrogen might not be the answer?
- Thread starter epicstruggle
- Start date
Oh really? So we can't eliminate losses of storing liquified and compressed hydrogen by using solid state hydrogen storage, or metal hydrides? Oh, and there's no way to obtain H2 other than by electrolysis utilizing the age old technique, nevermind biotech and nanotech.
Then the author glosses over the whole problem of electricity storage, which traditional batteries are terrible at from a density, lifetime, and pollution point of view. He does not mention the fact that if you don't use hydrogen for storage, you'll have to use flywheels, thermal, compressed air, superconducting rings, or some other form, such as a futuristic nanotech chemical battery that hasn't been invented yet.
The electric car died because the batteries were immensely expensive and had a high failure rate. Even today, if the electric batteries in a hybrid break down, which they do (MTBF 5 years), they cost anywhere from $1000-$5000 to replace.
Moreover, there is little discussion by the author of the total amortized cost per driver to upgrade the entire electricity grid, for the current grid cannot carry enough power to recharge 100 million vehicles everynight, in addition to powering everything else.
Yes, it is probably the case that hydrogen will never be as efficient as lithium-ion storage, then again, will lithium-ion storage ever reach the energy density of gasoline or fuel cells by weight? Or the reliability of internal combustion or fuel cells?
The author seems to have his own axe to grind, his "electron economy", but conveniently doesn't cover the third possibility, that we'll all be driving flex-fuel vehicles using biodiesel or other renewables and won't be using electricity at all, because the efficiency of biological processes at storing solar energy densely still rules everything.
That wasn't really a very good article Epic. Last I checked we had plenty of water, it is fresh water we need more of. IT specifically says water is becoming rare, that is dumb. There are many other places where it says dumb things as well. I am not saying hydrogen is the answer, and I don't even personally think it is all that viable, but this article is nothing new or interesting on that front. It is just more of the same old complaints, which by the way are not really accurate. Such as saying it isn't worth while since you don't get as much energy out as you put in. Well if you made fossil fuels from carbon and hydrogen you wouldn't either it all depends on what you start with. If you tried making coal you sure would find it a wasteful process too. What you say nature already made it through the use of tons of energy? Well then you should talk about SMR formed hydrogen...
Mintmaster
Veteran
You have any links about these possibilities? They sound interesting.
Anyway, I'm pretty sure that whatever's the cheapest way of making hydrogen is what'll be used. AFAIK there's a long way to go before any technique will approach electrolysis let alone steam-reforming and whatever's used in IGCC. I'm not particularly convinced about the carbon sequestration that'll be necessary for those methods of hydrogen production to help the environment. (I'm rather cynical that anything but coal will be used for the majority of power generation for many decades.)
For the very long term future, though, I'd hope we eventually stop using fossil fuels for electricity, in which case hydrogen makes sense.
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tongue_of_colicab
Veteran
hehe than we will see russians drinken out of their cars 
The efficiency of hydrogen production can't be calculated by using electrolysis alone. The electrolysis process today, takes energy generated by burning very high power density fuels stored over millions of years, and puts them on the electric grid. If you use electricity like this to power electrolysis, you then have to compress/liquify the gas, and store it, and after accounting for the entire pipeline, one ends up with woefully bad figures for electrolysis (something like 15-22%) This is how the real economic efficiency of a fuel source is calculated, and in that regard, using electrical grid power from other fuels to power electrolysis, to store it, to power fuel cells, is pretty terrible and one can argue you are immensely wasting the already converted electrical grid power.
If on the other hand, you don't use electricity already on the grid, but instead, produce it via say, photosynthetic processes in algae, or fermentative processes in bacteria, the same economics don't apply. Now one has to calculate the costs of the inputs and storage. For algae in a bioreactor, hooked up to a fossil fuel plant's flue gasses, the inputs are cheap. So the remaining costs are related to maintaining the bioreactor, and converting the results into usable fuel (methane, ethanol, hydrogen, etc)
The university of Berkeley recently succeeded in making Algae that produces hydrogen 100,000 times better than standard algae, and that's before they really did any serious genetic engineering. They just identified a pathway, and put the Algae on a diet devoid of sulphur to switch on a dormant gene. If they can get another factor of 100 better by further engineering, Algae bioreactors will be economically cost competive with *coal* according to them.
Sure, maybe the Algae still aren't as efficient as plain ole electrolysis, given that they have to spend energy doing other stuff, like cell division, but sunlight is an abundant and free input, and algae are cheaper to manufacture than additional electrolysis tanks, additional coal plants, and additional solar cells.
The other issue with "old style electrolysis" is separate production and storage. I read proposals years ago for combination cycle systems, using future nanotechnology. The idea would be your storage tank does the electrolysis. For example, you build a solid hydrogen storage system using a mesh of nanowires (typically nanotube-like). The anode/cathodes are nano versions, which sequester the hydrogen into a prison, and transport the oxygen away, where it may be used to recover some energy. It's sort of like hydride storage, only the hydride itself can exist in either "electrolysis mode" or "release mode" If it could be made to work (and there is no theoretical reason why it couldn't), it would alleviate a major problem today in the H-economy, which is first H2 is produced by electrolysis, then it must be distributed through expensive (to make and to run) systems, and compressed, or liquified into storage tanks.
Even onsite production doesn't get around the losses, since even if you use a hydride to store the hydrogen, you still must pump it in at sufficient pressures to pack the metal, and then you have to cool the hydride unless you want to melt someone's car, since the storage process releases tons of heat.
As for CO2 sequestration, if you look at a company like GreenFuel, they install an Algae bioreactor on the CO2 stacks of your Coal Plant, and remove 40% of CO2 and 86% of NO2, with no modifications to Algae. Far from sequestering it, one feeds it to algae to produce methane, ethanol, and H2, or one feeds the algae to something else to get more of what we want, nor neccessarily burning it for energy (which might release GHGs)
Might sound crazy at first but I think that is exactly what's holding back the process on the political side. Ethanol would be great but that's exactly the alcohol you knock yourself out with, and as such it carries high taxes in most countries. Building a large energy economy on ethanol would open many avenues for tax circumvention and also for just theft and getting shit drunk.hehe than we will see russians drinken out of their cars
Methanol is somewhat consumable but toxic (makes you blind among other things). You'd constantly have to educate people not to drink it (it makes you drunk too, so it has that attraction).
Propanol AFAIK is pretty hard to get from just letting plants rot in your bathtub. It takes some extra energy to get those longer molecules, and that's bad for overall energy efficiency/cost. It's toxic too.
WhiningKhan
Regular
For supplementary energy, sure. But do you think we can get enough booze to replace fossil fuels?
Quoted from quickly-googled Cornell University news item. And that's only talking about US and gasoline for cars, not a total ethanol economy.
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tongue_of_colicab
Veteran
Cant they just add a dirty taste to it? thats whats happens with ''spiritus'' (wouldnt know how its called in english) too. That stuff basically is alcohol and water but they added a dirty taste to it so people wont drink it. But in russia you have the same stuff but without the bad taste so people just drink it instead of wodka because its cheaper since there are no taxes on it (its supposed to be for cleaning windows and stuff like that).
The thing is that fossil fuels won't last much longer and something needs to be done. Whatever that something is, it won't need to beat gasoline because when this becomes relevant gas will be impractically expensive. It just needs to beat hydrogen and I think it can.
Re that article, corn is probably very far from optimal. You want something that grows fast at any time of the year, and with high sugar content if you can manage. Classic food-oriented agriculture won't solve all the challenges there, but think multi-layer algae fields in water tanks on rooftops. On the ocean. Restricting yourself to corn seems just so artifical, it's almost the worst possible choice they could have made to throw out the idea. Even if you don't go all-fancy there are a number of "classic" agriculture products that perform better.
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Umm you are not up on that then
SMR is 78% efficient. The very best electrolysis is somewhere below 45%
Or as wiki says
http://en.wikipedia.org/wiki/Steam_reforming
I am actually fairly informed about this topic.
The thing demo talked about also was achieved as I understand from trying to shorten the wee little arms that collect sunlight to allow it to penetrate deeper in the vat of organisms.
Unfortunately it is cyclical in nature and they are not making a sustained output that high.
None of these solutions solve the artificial "problem". They are all vastly less efficient than oil and nuclear. That is why we use, oil.
They're all very painful failures to a "problem" that is politically motivated, and can only end when civilization stops using energy (and therefore dies).
________
Web Shows
They're all very painful failures to a "problem" that is politically motivated, and can only end when civilization stops using energy (and therefore dies).
________
Web Shows
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tongue_of_colicab
Veteran
Civilisation managed without electricity for hundreds of years so I dont think it will be such a big deal. Sure, the world as we know it will change alot and some things will get worse but would it really be that bad if we all went a hundred years back? Sometimes I do feel bad we dont have things we had back than anymore.
Saying oil is stupid.
Try producing oil from water and CO2 and see what kind of efficiency you get?
It isn't an artificial problem, it is a real problem unless you happen to live in Saudi Arabia.
Using methane to produce hydrogen is very high efficiency, the problem is still really in storage and transport. The solid state storage described might work out, but it might not.
The thing is if you use SMR you might as well just use the methane itself, but then you are back to pollution.
There are many industrial plants, that produce hydrogen as a waste product. Like with the production of ethylene for plastics production. They filter out that, and simply burn everything else to power the reaction. Adding a second filter stage might make a lot of sense, and produce hydrogen very cheap.
WhiningKhan
Regular
There are, yes, but sugar beet still gives only something like double the ethanol yield. So, only half of all land area would have to be used for this single purpose...
The point of that article was exactly to bring out the downsides of the existing corn-based programs.
But whatever plants would be used, I have a gut feeling that the distributed infrastructure for handling an operation of that scale would set remarkable challenges for its economics. I hope it works out, but I don't see why we should concentrate only on ethanol as you suggested. Eggs in one basket and all that.
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