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Renewable Energy: How to power the world without burning dead things
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Edit: Hmmmm. Let me first suggest you back off any simplistic explanations of the role of any particular greenhouse gas within our atmosphere, especially water vapor. There a vast sea of little details that your analysis is ignoring, although I personally tend to agree with your view of the relative importance of H2O emissions as an issue for the developers of a hydrogen economy. That said, I'd just like to point out that the gas that is attributed with the inglorious identification as having the highest impact on the greenhouse effect is water vapor! Check the greenhouse gas wiki. :^:
The fact is, that the time H20 is held in the atmosphere is completely irrelevant to measuring atmoshperic WV's greenhouse effect. The flow of water from evaporation to precipitation produces an average amount of water vapor present in the atmosphere (in tons for example) and it is the average amount of WV in the atmosphere that determines the overall thermal impact from WV's greenhouse effect not the airtime of a single molecule of water. Increase the average amount of water vapor for a period of time above some known point and you will see an increase in the warming effect. Currently the greenhouse effect of the existing flow of water through the atmosphere dwarfs CO2's greenhouse effect, and WV is currently a reactive greenhouse effect generator, though that would no longer be it's only role in hydrogen energy infrastructure. It is a positive feedback mechanism thought to magnify the effect of other greenhouse gasses, and may be the primary reason smallish increases of CO2 or other trace greenhouse gasses can have a large impact (secondary effect of warming). No one is certain that using a much more efficient method of creating WV (like a hydrogen fuel cell) instead of combustion on current scales would improve overall global warming trends or even maintain the status quo.
Above and beyond the greenhouse effect caused by water vapor, WV content is part of the measure of atmospheric energy (heat), because it represents heat not detected as sensible heat (Geology 106). So water vapor not only has a Greenhouse effect, but also has a heating effect in and of itself thanks to water's well know thermal properties that requires huge amounts of heat per gram to convert it from a liquid to a gas (it takes alot of kenetic energy to become a gas thanks to H2Os dipole natue). 8-)
You might want to be a little more open minded to the potential problems of fuck-tons of additional water vapor in the atmosphere on average, produced by a hydrogen fuel infrastructure on the scale of our current energy infrastructure, before you want to speak for the universal worries of climate change scientists.
I was about to mock you for the second half of your question, but then I remembered fusion.
So no, not yet.
The quantity of water in the atmosphere is held in a tight equilibrium via the hydrological cycle. If you pump more water vapor into the atmosphere it will rain out somewhere else. This is what ELM is talking about when says that the water's residence time in the atmosphere is too small to make a difference. There are similar mechanisms operating on CO2, but they occur over a much longer scale--millenia rather than days. Think about it this way--70% of the planet's surface is covered in liquid water. If a bunch of extra water could hang around stably in the troposphere it would already be there. Changing the temperature of the atmosphere will change its H20 content, but I'm extremely skeptical that simply pumping more water into the troposphere will make any difference whatsoever. It is especially absurd to think that the water created by a fuel cell will contribute to global warming since these can easily be made to produce liquid water instead of steam.
And your whole point about water vapor "having a heating effect in and of itself" due to its high specific heat is nonsense--it literally does not make sense. Condensation is exothermic--but the evaporation that put that water there in the first place is endothermic. I can't even tell what you're trying to get at, here. That the atmosphere's thermal conductivity will change as a result of changing humidity? That its average temperature will be made stabler? What are you saying?
Besides, we produce a ton of steam using all conventional power sources anyway.
[Edit: Also, hydrogen (except when fused) is not a power source--it's a storage mechanism. The efficiency of the process is borderline irrelevant; it's the ease of distribution, the per-unit cost, and the power density that will matter. That you lose energy on the whole is to be expected; we can easily replace that energy with some baseload power source of your choice--fission, solar, whatever. A fuel cell is much more like a battery than anything else.]
Just wanted to highlight some funny!
Ok, I take most of your points duders. I'm fully aware that this is a non-issue compared to the feasibility issues inherent in a hydrogen economy, but thank you for bringing up many additional examples of major problems with hydrogen power. In particular, my points are irrelevant if you simply make liquid water instead of water vapor, but that depends entirely on the actual fuel cell technology that ends up dominating such a hypothetical future energy market. The methane fuel cell I'm aware of (the Bloom Box) makes water vapor, I believe, so I might have over-generalized.
<Cue 10 examples of fuel cells which produce liquid water not water vapor.>
I was under the impression, that to get the same amount of usable energy out of hydrogen oxidation reactions as octane or methane combustion reactions, one would produce more water, but I'm willing to learn if I'm wrong. I thought this was because the energy captured for work is much smaller in a single hydrogen oxidation event than in a single combustion event, even assuming a much higher efficiency energy capture.
The major point I still disagree on with you guys is whether or not the lifetime of water vapor in the atmosphere is actually relevant to the heating effect it produces. Again, water flows in and out of the atmosphere and I acknowledge that, and water acts as a heat transport mechanism taking heat from the ground into the air vice versa, yes. However, in doing so it produces a layer of moistened air which has both a kinetic heating effect on the atmosphere, as heat is transported by water from the earth to the atmosphere, and it also produces a greenhouse effect by absorbing other light frequencies and emitting IR (similar to CO2 - look at the absorbtion band on the greenhouse gas wiki). It's like a blanket around the earth, that can grow or decrease in thickness (ppm of atmospheric content) and when it grows, it prevents additional heat from escaping just as when you switch to a thicker winter blanket for additional heating effect.
The fact that effects are somewhat transient seems to only be relevant in low frequency events or if you were to discontinue the continuous production of water vapor, but when you add a definite amount of additional water above and beyond natural processes continuously, as one would in an H2 economy, then there should be an increase in global warming. I think the assumption you guys are making, that when you add more water to the atmosphere then you just get more rain, is problematically simplistic at best. In addition, as the atmosphere heats, it's capacity to hold water vapor increases, and so as water adds more heat to the atmosphere the atmosphere in turn can hold more water (positive feedback). This increase in the average tonnage of water in the atmosphere above and beyond natural processes must to produce additional heat beyond natural processes even if that is a mostly short lived effect once the man made processes are no longer being performed. Perhaps we won't see that occur if the right fuel cells are in place, but right now we can only speculate what waste would be emitted by future hydrogen fuel cells, and my point is that under the right conditions water vapor could be considered one of those waste products.
Let me also mention, that while industrial activity does produce a hell of a lot of steam (I agree with you here CycloneRanger), most of that is contained within closed systems so that the stream can be put to work, spinning turbines and the like. I don't have a hard number on that, but knowing some sites I've worked at where they have boilers, they don't really want to lose any steam, because it does things.
However, now that I think about the problem more, I think I know of a way around it.
Instead of generating the H2 by electricity from the fuel cells which generate electricity from the H2, simply use something else to obtain H2 to begin with. Obviously, it would be pointless to burn shit to achieve, but you could use wind and solar to either obtain H2 through electrolysis, or I've heard that some kind of solar cell could be made that would simple use sunlight to obtain H2 directly. Either way, the nice thing about this approach is that it solves both the energy storage problem that wind and solar introduce, and the H2 generation problem for a hydrogen economy. Unfortunately, you must still solve for the storage and transportation problem. You'd need to come up with a pipeline design and other storage devices which can actually hold H2, but hopefully that's not an intractable problem.
Edit: On H2 storage - has anyone created an H2 storage chamber based on electromagnetism? Physical materials tend to be much too porous to hold in H2, but what about EM fields? I can imagine a rail car sized chamber that's constructed out of permanently magnetic materials, where the field strength would be just high enough to prevent the H2 from passing through the containment wall at storage pressures. No idea if that can be done, though.
Yes, it is by far the biggest greenhouse gas (Worth about 35 degrees C of heating if i'm correct). But it can't stay up, due to thermodynamics. And changing a degree or so in surface temperature doesn't change much to this balance.
In a hypothetical world in which there are no man-made adjustments to global greenhouse effect until we introduce a hydrogen economy, then we might see something along the lines which you describe, because the flow velocity of water through the atmospheric component of the hydrologic cycle might speed up without producing a denser average layer of atmospheric WV, but I very much doubt it, because of the Clausius-Clapeyron relation. Here's the nut: what would cause an increase in density of a greenhouse gas in our atmosphere? If the incoming flowrate is larger than the outgoing flowrate, then density will increase, and opposite is true as well. What you guys are arguing is that WV evaporation and condensation are so tightly coupled that an increase in incoming flow will guarantee an increase in outgoing flow, but this is an assumption backed up with no data or empirically derived physical laws, just hearsay. In fact, given the Clausius-Clapeyron relation this assumption is almost certainly incorrect.
What I'm getting at is that the only factor that makes a shit's worth of difference in terms of any greenhouse gas's effect on global temperatures is its average density over a given period of time, given a certain amount of insolation, and water vapor is no different (insolation = energy from the sun, not insulation which is simply thermal exchange shielding for those that don't know). The flowrate of a greenhouse gas entering and leaving the atmosphere has little to no bearing on the average temperature rise caused by those gasses, unless a corresponding change in average density occurs due to said change in flow velocity.
;-)
I don't understand why this phenomenon gets a pass from global warming scientists when we know that along with billions of tons of CO2 per year we inject into the atmosphere, that we are simultaneously injecting billions of tons of excess WV. However, I'm afraid I've made this topic more important than it really is, because there are many more critical problems with a hydrogen economy that have to be solved before we could possibly run into the situation I describe. I wonder if anyone has tried to test the associative link between increased average global temperatures, and increased WV density? If someone actually made the measurements, I haven't seen them, but it would be a quick way to prove/disprove me if someone can come up with that empirical evidence and show that the rise of global temp is not associated with a rise in the average density of atmospheric water vapor. (I'd look , but I'm at work and these things take too long just to type)
1) There already is 100x as much water in our lower atmosphere then CO2. So it's much harder for humanity to influence.
2) This water has a very short "cycle time." It falls down and goes back up all the time, it never migrates to higher levels of atmosphere. So anything we pump up comes down too.
3) This cycle is completely dominated by the amount of surface water, and the temperature at the surface.
When the global temperature rises, yes the amount of water that can be held up increases. Yes this may be a positive feedback, in that the extra water adds some extra global warming. But that doesn't mean it holds itself in place when the CO2 levels finally start to drop (note that this will take decades if not centuries, even if we stopped emitting right now). But here's the catch: If we stop all CO2 emissions, AND all H2O emissions (from burning CxHy and from H2), the amount of water in the air would still be exactly the same. Because the seas dominate anything we can do in that regard. We can't stop the seas from reacting to the global temperature increase in the most basic of thermodynamic ways.
I have never read or heard anything from anyone approaching an expert that releasing more water in the atmosphere is a long term problem. You are the one positing this, please back that up.
I never said that the CO2 emitted = H2O emitted, because that would clearly be the case only by happenstance.
As I said before, cycle time is mostly irrelevant for determining greenhouse warming effects for all greenhouse gasses. Only average density controls warming from greenhouse effect, because density, not cycle time, determines how much sunlight is transformed into IR by H2O, CO2, methane, etc. and sent to earth's surface. Average density may or may not be affected by changes in cycle time, but the onus is on you to show that relationship as established by empirical testing.
That is a huge leap. There is a big difference, millions of tons of water, which on the scale we are talking about is minuscule, but it is an exaggeration to suggest things would be "exactly the same".
Thank you for establishing that neither of us are experts in this field, though I never pretended to be. I'm just applying deductive reasoning and evidence to a number of claims and trying to make sense of it all. I'm not infallible, no one is, and I never claimed to be. I simply find the evidence enumerated thus far against WV being a global warming problem not very convincing. I'm not trying to prove that WV causes global warming (though surely there is a component that is due to WV), but rather I'm trying to disprove that there definitely is NO problem from emitting WV.
Just to clarify, I never said that WV emmissions are currently a problem or even a real long term problem at this time, because it seems like it would only have the potential to become an issue with a future hydrogen economy. It may never be a real problem, it might be one now that we have overlooked, I'm not final arbiter, so I won't claim that I know with 100% certainty which is the case. In fact, I'm simply defending the only guy in this thread so far with any connections to the future hydrogen infrastructure: TheGerbil (well I'm defending his buddies concerns actually). He's working on the H2 storage problem, but he works with scientists who are looking at a hydrogen economy from many angles, including scientists who do believe there could be a H2O emission problem.
I objected to electricitylikesme's blase rejection of actual working scientists concern over this issue as originally raised by TheGerbil, as simplistic in the extreme and ultimately unconvincing. Read back a few pages and you'll see what I mean. I found his citing of the chemical formulas as evidence as overly-simplistic and insufficient cause for the working scientists that TheGerbil cites to stop caring about such a potential problems while they work to develop components of a hydrogen economy.
You might be right, but don't forget that WV is also one of the bigggest positive feedback mechanisms as well.
I cannot guess what the TheGerbil tried to say, but it could mean a local effect. Which I guess is possible, but certainly not very likely. Note that current cars already produce about half as much water as a pure H2O cell with the same efficiency would (And H2O cells have higher theoretical efficiencies then internal combustion engines). Noone ever seems to complain about that.
I am not an expert in climatology, but I do have a background in physical chemistry (though any direct dealings with thermodynamics have been a few years)
Here's the thing: the reason cycle time with CO2 becomes a problem is because the rate of mass flow into the atmosphere is higher than the rate of mass flow out of the atmosphere, not because of the length of the cycle time in and of itself. This imbalance causes higher densities of CO2 than would otherwise exist in our atmosphere, which causes more heat to reach earth or be trapped in earth's systems.
This could also be the case for H2O, under the right circumstances in my opinion, but I'm not sure anyone can speak definitively on that.
The thing I've been trying to get across to you on the cycle time issue is that our emissions are continuous not discrete, so that by the time that 9th day rolls around and rain falls you have 8 more days of evaporation in the atmosphere, that are still waiting to be removed. The key to determining WV global warming/cooling effects is in determining the average density present in the atmosphere, because higer density = greater number of water molecules. Each H2O molecule sits up there for 9 days turning other frequencies of light into IR, so when you increase the number of H2O molecules on average present in the atmosphere you will increase the amount of IR sent to the earth thus increasing heat. Again density will increase if there is an inflow and outflow imbalance where more goes up than comes down, and maybe we could eventually be in that scenario.
Actually, you could just grind the bricks up, mix them with soil and dump them back in the ground. Nuclear waste management is a ~100 year problem, not a millenia problem. Pretending that it is is a concession to anti-nuclear groups.
But the reason why water isn't such a big deal is that it's 'decrease mechanism' (rain) responds hugely quickly to increased water levels. Pump up more H2O and don't increase the temperature and it will simply rain more. Each day will have a little bit more rain than it otherwise would have.
Compare this to CO2 where the decrease mechanism (being captured by organisms and slowly ground back into the core of the earth by crustal plates) is almost independant of the amount of CO2 there is and responds very slowly where it does respond.
That said, I do like your idea and I would extend it to suggest that we eliminate nuclear waste in this fashion until thorium reactors are made or breeders become usable by our energy sector, by combining nuclear waste with the raw sewage product "biosolids". Suddenly the biosolids market would grow and we wouldn't have to worry about them using our shit as fertilizer and feeding it back to us! ...Now where did I put that mile deep hole...
Two birds one stone!
That's an interesting assumption, but ask yourself - does it actually correspond to reality?
The issue with nuclear power in the US is entirely a public perception problem. Largely caused by a bunch of environmentalist who refuse to acknowledge their role in global warming by forcing coal plants to stay in use that could have been replaced with nuclear plants because apparently "nuclear" is a bad scary word to people who won't spend a day to educate themselves on something before they decide to hate it.
Did you see that I was responding to tbloxham's comments and not your earlier comments?
Did you notice I was making a joke about combining nuclear and human waste? (Perhaps the dirtiest kind of joke
Come on dude, you're smarter than that. I was won over by your superior plans for treating nuclear waste several pages ago. The only thing I pointed out is that there are still regulatory hurdles to overcome to turn such plans into action, but I'm still convinced that it's a worthwhile idea.
On a related note, having read the wikipedia article on greenhouse gas, I did not find any source for either of the following edit: the closest I found was on the wikipedia page for carbon dioxide, which still doesn't indicate that magnitude, but does at least cover it.
Someone post something hopeful to help me sleep.
edit: cant find the vid. I said "boned" above, but the presentor simply stated that we would feel the effects of dwindling (affordable) fuel in a big way.
I apologize on stating the wrong source to backup my knowledge about the Ocean as carbon sink. I'm sure it was something on the discovery channel or NPR that taught me that originally. I didn't know there was any continuing controversy over that point, since I learned about that years ago, so didn't really follow through.
If you're going to make a claim and expect us to believe it, you need to provide a source (I'll admit Wikipedia is actually a terrible one, but its easy and they usually do cite decent ones). An unspecified Discovery Channel or NPR show is not a source, although if you could provide a name that'd be at least close.
Until then, your point has no support and should not be taken seriously by anyone.
edit: For the TED video, he seems to dismiss nuclear pretty quickly, and I'm not sure that I buy his dismissal. He also doesn't consider thorium based fuel cycles that I caught. I'd agree we need to get fusion working, but the 5-10 years thing ... well, mostly it makes me think I found the wrong video.
Still not sure where you need a citation from me? For the Oceans as carbon sink? I thought you just said that you found corroborating evidence on the Carbon wiki? It'll have to wait until later if that's what you're requesting, cause it's time for me to commute home and pollute the shit out of this place.
Edit: As for people taking me seriously, meh. In my very short experience here when people take me seriously here they're just looking for an argument, which I'm more than happy to provide most of the time, but it's not really an important goal of mine here at Penny-Arcade's forums. I'm here for fun, to learn, and to have interesting discussions of things I'm not an expert in with other non-experts. Maybe you ought to take yourself less seriously before you give yourself a heart attack?
If the goal from a discussion is to learn something about a subject you don't know about, do you have a plan for making sure what you're learning is actually true that doesn't involve sources?
You're still attacking the wrong target, so save your energy and find someone who actually disagrees with you to get all snarky at, dude.
Fake Edit: BTW, what exactly is your background or connection to nuclear energy to begin with??
Real Edit: I will get you a citation for the Ocean carbon sink issue, but please be patient.
Oceans are the single largest carbon sinks. Doesn't mean it helps us much though, the ocean is slowly acidifying as the CO2 concentration in the air increases, which has all kinds of nasty concequenses (primary: slowly dissolving coral reefs and heavy outburst of big algae patches)
Let me point out to Syrdon, that the image is from 1996, so it has been pretty well known for some time that the Oceans are the largest carbon sink. That's part of why I genuinely assumed it was common knowledge; that and I've heard it from many sources since I first learned it. It really stuck out in my mind, because I had also thought that plant life was the major carbon sink of the planet for pretty much the first 12-15 years that I knew anything about global warming.
Can't watch it but I'm assuming it's like the peak oil doom crowd though, he discounts economics (that people will not necessarily use as much power as they do now in the face of higher prices), and it sounds like he gives nuclear the short end of the stick.
See a presumption that we'll be unable to generate enough power in 5-10 years are as valid as presumptions we'd be out of water by 1980 (made in 1970) or that the top soil would all be gone (made in 1950) by the 1970s.
Both of those issues are problems and serious concerns, but we didn't just run along until everything was fucked. There are actually people, serious people, and even mega corporations who don't want to see it happen. America, for example, if we just switched to CFLs we'd save fifty two fucktons of watts. Californians use half the electricity of the rest of the US per capita, and that's not all from heating (since the south is included in that), so discounting the demand side changing is kind of absurd
Why does energy consumption keep increasing, and why does it need to keep increasing?
Seriously, why don't we all just take a little time to make sure that we actually use as little power as possible on a daily basis, because it only takes a little effort. Switching to CFLs cut my electric bill in half when I lived in an apartment, and still represent a 30% reduction in electricity costs vs using incandescent bulbs to me now that I own a home. If people knew how easy it is to save lots of money (with the side benefit to us all of using less energy) without changing your lifestyle fundamentally, then people would be all over that shit, but most people haven't even thought about it.
Check out some articles for simple efficiency improvements from the magazine Home Power.
First Steps
Basics
Details
Eliminate Standby Energy Losses
good luck getting people to do that though =/
heck, we 'let it mellow' and doing such, we save over 8,000 gallons of water a year .... no problem.
edit: It's so easy to save energy, the fact is, most people can't (won't) be bothered