Guest Post by Willis Eschenbach
As a result of my post on energy storage entitled Getting Energy From The Energy Store, a few people brought up the idea of replacing our current energy sources such as gas and oil with hydrogen (often written as H2, because two hydrogen atoms make up one hydrogen molecule).
You see this on the web, that we could power our civilization on hydrogen, convert all the trucks and buses to run on hydrogen, they call it shifting to a “hydrogen economy”… and why not? You can burn hydrogen just like natural gas, you can run an internal combustion engine on hydrogen, what’s not to like? Here’s a typical intro to an analysis:
A Comparison of Hydrogen and Propane Fuels.
Hydrogen and propane have long histories of being used as fuel. Both fuels can be used safely if their physical, chemical, and thermal properties are understood and if appropriate codes, standards, and guidelines are followed. Although the properties of hydrogen have been compared to those of propane and methane, these comparisons were made to facilitate appreciation of the physical and chemical differences and similarities among these fuels. It is not possible to rank these fuels according to safety because plausible accident scenarios can be formulated in which any one of the fuels can be considered the safest or the most hazardous.
So what’s wrong with this comparison, between hydrogen and other competitive fuel sources like propane and methane?
What’s wrong is that people misunderstand hydrogen. Unlike say propane or methane, hydrogen is not an energy source. There are no hydrogen mines. You can’t go out and drill somewhere into a deposit of pure hydrogen and bring it back home to burn.
And why can’t we mine or drill for hydrogen and bring it home and burn it to power our cars?
The reason we can’t mine and burn hydrogen is simple … it’s all been burnt already. The nerve of nature! I mean, people are always warning that we’ll burn up all the fossil fuels, and now we find out that nature has already gone rogue on us and burned up all the hydrogen …
Figure 1. Burnt hydrogen, showing the hydrogen and oxygen atoms.
Most of the burnt hydrogen we call “the ocean”. Another bunch of burned hydrogen we call ice and rain and rivers and lakes. But there’s no hydrogen that is available for drilling or mining—it’s all bound up in other compounds. And as a result, hydrogen is not a source of energy—it is merely a way to transport energy from Point A to Point B.
[UPDATE April 17, 2023: It’s been pointed out to me that there is one small hydrogen well in Africa, and that there is hydrogen produced naturally by reactions with water in the depth of the earth. However, as far as we know currently, it only collects in commercial quantities under very unusual conditions. Most is constantly escaping in tiny seeps. In addition, the global annual geological H2 production, not usable production but total production, is estimated at 23 Tg/year, which contains energy equal to less than 1% of the world’s annual energy usage. A possible future energy source for the globe? Seems doubtful, but it’s early days, time will tell.]
And this in turn means that the main competition to hydrogen, what we should be comparing it to, is not natural gas, nor propane as the quote above says, nor any other gas.
Instead, the main competition to hydrogen, the true comparison, is to electricity, which is our current means of transporting energy. Saying that we could “power our civilization on hydrogen” is as meaningless as saying we could “power our civilization on electricity” … neither one is a source of power, they’re just different ways to transport energy around the planet.
This is not to say that hydrogen is not useful, merely to clarify what it is useful for—transporting energy from one place to another. It is not a source of energy, it is a way to move energy. This distinction is very important because it lets us make the proper comparison, which is not comparing hydrogen to propane as they did above, but comparing hydrogen to its real competition—electricity.
Now, compared to electricity as a means of transporting energy, hydrogen suffers from a number of disadvantages.
The first disadvantage results from what I modestly call “Willis’s Rule Of Small Stuff”, which states:
It is far easier to move electrons than to move molecules.
This rule has ramifications in a number of fields, particularly the transportation of energy. For example, consider the difference between moving a large amount of energy on a constant basis over say a hundred miles (160 km) by the two competing transportation methods, electricity and hydrogen.
For electricity, you just have to move electrons. So you string a pair of copper wires up on poles from Point A to Point B, and … well … that’s about it. You hook one end to a generator of electricity, and a charge appears at the other end of the wires. There’s not much leakage, not many problems of any kind. The system is robust and relatively safe, and able to withstand storms and temperature extremes.
Now, consider moving the same amount of energy as hydrogen. For that, you have to move molecules. First off, you need a pipeline. Now, we’re all familiar with pipelines for moving energy. The trans-Alaska pipeline is a fine example. Pump oil in at one end, add some pumping stations along the route to keep it moving, and oil pours out the other end.
Hydrogen, though, is a very difficult beast to pump through a pipeline. To start with, hydrogen has very, very low energy density. So you have to pump a huge amount of it, about 4,000 times the volume of gasoline or oil for the same energy.
Next, hydrogen is incredibly sneaky. Do you know how a rubber balloon filled with helium gradually loses its helium over time? The helium is small enough to go through holes in the rubber balloon, tiny holes that are too small for air to pass through. Well, hydrogen is even worse. It can escape right around a piston in a pump, and run happily out through the pipe threads in any pipeline connectors. It requires special gas-tight connections from end to end of the delivery chain. You can’t just stick the hydrogen pump nozzle into your gas tank like you can with gasoline or diesel. So moving the molecules of hydrogen turns out to be a much, much harder problem than moving the electrons with electricity.
The second disadvantage of hydrogen as a means of transporting energy is the low energy density mentioned above. In general, the energy content of fuels varies with their density. So for example, diesel has more energy per liter than gasoline, which is lighter. And alcohol is even less dense, so it contains less energy per liter than either gas or diesel.
Now, consider hydrogen gas. Figure 2 shows a chart comparing various materials regarding energy density in two different measures—megajoules per liter (MJ/L), and megajoules per kilogram (MJ/kg).
Figure 2. Energy density of selected materials. Vertical scale is in megajoules per litre, and the horizontal scale is in megajoules per kilogram. Hydrogen is at the lower right. Click to embiggen. SOURCE
This leads to an oddity. Hydrogen gas has a huge amount of energy per kilogram … but almost no energy per liter. Gasoline holds about 35 megajoules per liter (MJ/L). But even compressed at 700 bar (about 10,000 psi) hydrogen has only about 5 megajoules per liter. That means that you have to move a lot of hydrogen, or pack a lot of it into a car or truck fuel tank, to have enough energy for practical purposes.
Now folks are always claiming that this problem will be solved by adsorbing the hydrogen onto the surface of an as-yet-unknown sponge-like substance from which it can be recovered as hydrogen gas by heating the substrate. But that can’t possibly be as energy-dense as liquid hydrogen, and liquid hydrogen has only a measly ten megajoules per liter. So adsorbing it will not solve the problem.
Nor will liquefying it, seeing as how you have to keep liquid hydrogen at about 240 degrees C below zero (-405°F) … not practical.
And that means that if someone wants to store much energy, say at a hydrogen fueling station, well, they’ll need a whole lot of high-pressure tanks with special fittings, and they’ll need to be about six times as large as the corresponding gasoline tanks to contain the same amount of energy. Or if they are storing the hydrogen adsorbed onto the surface of some as-yet-undiscovered material, they won’t need to be high pressure, but they’ll need to be even bigger.
The third disadvantage of hydrogen as a transportation medium is safety. Yes, electricity is dangerous, of course. But electricity isn’t flammable, and hydrogen is extremely flammable. Hydrogen has an unusual quality. Most fuels only burn when there is a certain ratio of fuel to oxygen. But hydrogen will burn whether it’s a little hydrogen mixed with a lot of air, or a lot of hydrogen mixed with a little air. Not only that, but the hydrogen flame is colorless, smokeless, and invisible in sunlight … a very bad safety combination.
The fourth disadvantage of hydrogen is something called “hydrogen embrittlement”. Here’s a crazy fact. Hydrogen molecules are so small that they can leak out through solid steel. It can either react with steel, or it can leak right through the steel. But that minuscule slow leakage is not the real problem. The real issue is that hydrogen penetrating into and through the metal lattice weakens the steel, fatigues the metal, and decreases fracture resistance. In the long run, it can embrittle solid steel to the point where it cracks all the way through after only a slight impact.
The final disadvantage of hydrogen as a transportation medium is that after using hydrogen to transport energy from A to B, it is hard to convert the hydrogen back into other useful forms of energy. For example, electricity can be used to drive a crankshaft, heat a cup of tea, shoot a railgun projectile at supersonic speeds, energize a magnet, wash my clothes, power a laser, propel a train via linear induction, light up a football stadium, split water into hydrogen and oxygen, charge my computer’s battery, or to drive a chemical reaction against an energy gradient.
Out of all of those uses, hydrogen can drive a crankshaft with very low efficiency compared to electricity, and it can heat a cup of tea … yes, you can use hydrogen in a fuel cell to convert it back to electricity, but that kinda defeats the purpose.
I mean, isn’t it rather goofy to use electricity to create hydrogen, transport the hydrogen, and then convert it back to electricity??? What’s wrong with this picture? Why not just use the electricity directly?
All of this taken together, of course, is the reason that our civilization did not adopt the use of hydrogen as an energy transportation medium, and we settled on electricity instead … because, well, it’s kind of a no-brainer. For just about any purpose you can name, including transporting energy around for powering cars and trucks, hydrogen is well down on my list of good candidates.
Now, if I can just find out who burned up all the hydrogen and didn’t save it for the grandkids like Death Train Jim Hansen advised us to do …
w.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Eli Rabett says:
July 1, 2013 at 5:23 pm
As always Willis begins with an amusing troph about hydrygen: “But there’s none of it that is available for drilling or mining, it’s all bound up in other compounds. ”
without noting that the same is true of just about everything else, and those minerals, as with hydrogen, often come in oxidized forms.
No, it is not true. The fossil hydrocarbons we mainly use for energy production (and just about everything else) aren’t bound nor oxidized. If they would be, we couldn’t use them to generate energy by burning them.
Whole this “hydrogen economy” debate reminds me about the “car which runs on water” type of debate, which usually completely ignores basics of thermodynamics.
Hydrogen as the energy carrier (not resource – there’s almost no free Hydrogen in the nature) maybe can be useful for special purposes, mainly in space where the temperature is low enough and no oxygen around to relatively safely store it. But to base our earthly economy on it? I would think to believe in something like that is a simmilar absurd facts ignoring hype as is the CAGW hype, with the slight difference that while the CAGW hype mainly costs loads of money, the “hydrogen economy” is besides that also cappable to literaly blow things up.
Remember Challenger? An example what happens when something compromises a hydrogen tank. And that was NASA, the rocket scientists, who usually know what they’re doing and why. Imagine to give something like that to some environmentalist sect rednecks, who believe that to use hydrogen as fuel is just about almost something like to use diesel…
And any uncombined Hydrogen diffused into Space Billions of years ago. Gravity can’t hold it here in its elemental form, it’s too light.
David L. Hagen says:
July 1, 2013 at 5:37 pm
The best use of hydrogen as an “energy carrier” is to “chemically liquify” H2 by reacting it with CO or CO2 to convert it to Methanol (CH3OH).
Unfortunately Methanol is very toxic. Here in Europe the EU for example had the idea tha they’ll put it in the windshield cleaners to get rid of the overstock. Then some guys discovered a good bussines to buy bulk the ingredient and put it in the cheap spirits. The result was 39 dead, hundreds of blinds and otherwise impaired, unknown number of minor poisonings and nationwide prohibition until all spirits in the country were either controlled or destroyed.
http://en.wikipedia.org/wiki/2012_Czech_Republic_methanol_poisonings
I am all for hydrogen powered automobiles and truck but in one location only… Washington DC.
On second thought you can add NYC, LA and Boston too.
I also like Entropy, everything descends to it’s lowest energy state. I often use it to describe why cars rust.
A lump of Iron Ore spends billions of years being just that. It is very happy being a lump of iron ore as it is at its lowest energy state, it doesn’t want to do much, just sit there. But no, we know better.
So we come along and dig it up and then we inject huge amounts of energy into it and turn it into Steel, a material that is at much higher energy level. The Iron in the Steel responds as one might expect by seeking to return to its lowest energy state as quickly as it can. People have made careers out of seeking to slow down the reversion process.
Entropy tells you that there is no such thing as a free lunch. If that wasn’t true, then in the spirit of this example, why can’t we mine Steel ?
Two more items for consideration:
1. We don’t have a good cheap reliable hydrogen detector. (There are hydrogen detectors, but they also respond strongly to more common substances, like carbon monoxide. The solution is you have to have detectors for those other substances and subtract their signals to get just the hydrogen level. So there is no way to determine if you have a leak. As noted in the article, you can’t even hunt for leaks with a lit match effectively because you can’t see the flame.
2. Hydrogen can diffuse rapidly through hot metal, and more slowly through cold metal, causing hydrogen embrittlement. The really bad news is in steel hydrogen also latches onto the carbon atoms in the steel on the way through and converts them to methane so the steel is slowly weakened by decarburization.
Hydrogen in large quantities is tricky stuff to work with.
Another view on H2 http://www.minyanville.com/businessmarkets/articles/energy-F-tm-hmc-fuel-electricity/6/8/2009/id/22968
Well hydrogen will have its day “in the future”, when human kind gets all the energy we need from the top 1/16th of an inch of San Francisco bay. Well that is if they get to it before that top 1/16th becomes mud, like the lower levels of the Bay are.
Well if you note, I said “in the future.”.
I think gravity, is the only long range force that sucks. The other long range force electromagnetism , both sucks and blows all the time, which leads to Earnshaw’s theorem, that there is no position of stable static equilibrium, in an em field. No static configuration of charges is stable.
So gravity works well to hold fusionable fuels into a dense hot mass for long enough to ignite; it just has to suck in enough fuel to do it. We know it works with gravity, because we have one next door.
Willis Eschenbach says:
July 1, 2013 at 1:37 pm
Matthew R Marler says:
July 1, 2013 at 9:31 am
This is a silly post. Start with this: It is far easier to move electrons than to move molecules.
Lots more energy is moved in the form of molecules than electrons, as in oil tankers (ship, road and rail). oil and gas pipelines, coal barges.
Thanks, Matt, but dang … miss the point much? I didn’t say more energy was moved by electrons than by molecules. I said it was easier to move electrons than molecules.
So why do we bother to move the molecules at all? Burn them at the source and transmit the power over high voltage lines with the ~7% losses on the grid. Of course you know the answer(s) is that electricity is not an energy dense “fuel” due to the poor characteristics of batteries (or any electro-mechanical storage medium) and there are other requirements.
For a clear example, think about replacing the electrical grid in New York City with a fleet of thousands of tank trucks delivering the equivalent amount of energy in the form of gasoline, and then getting it up to the 85th floor or wherever the energy is actually needed … which one would cost more on an ongoing basis?
Here’s any even clearer example: home natural gas delivery. We seem to have come up with an infrastructure to handle that just fine. Why don’t all homes have electric heat? It’s easier to move those electrons, isn’t it? In fact I’m in the market for an affordable 5kW SOFC combined power unit for my house but they’re prohibitively expensive right now. My total thermal efficiency would be in excess of 80% with such a system using the little tube of metal that brings me CH4 right to my doorstep (well, south side of the house, actually). That is far in excess of the efficiency I get from a purely electrical system.
Here’s another example. Why do you think email is replacing printed letters with stamps?
Because it is cheaper and easier to move the electrons that make up an email than to move the molecules that make up a letter, particularly since to move the letter’s molecules you also need to move the molecules that make up the postman and his/her truck … electrons win again.
*sigh* Latency, of course. Now you can claim that that is because electrons are easier to move than molecules but you neglect the rest of the infrastructure problem. I can deliver essentially an arbitrarily large amount of data through mail if I want. Santa certainly has no trouble getting massive amounts of data every year in the form of real physical letters. I honestly have no idea how many e-mails, texts, or twits he gets. Up until relatively recently Netflix was sending FAR more data in the form of DVDs through conventional mail than streaming. I couldn’t find a quick link to the recent relative rates in the 2min I tried searching so maybe it’s already crossed over because of the latency thing.
Here’s a question for you: Since electrons are easy to move and photons are even easier, why don’t we all have gigabit to the home? There’s that pesky infrastructure again. And in many ways data is even easier than simple electrical power to lay (some, not all). But let’s use radio waves instead of conductors. That’s even easier! So why don’t we all have gigabit connections to our cell phones? I can tell you even with all of my 4G LTE bars and letters and cute little wave icons I’m sure as hell not getting even the 300Mbps I’m theoretically entitled to.
Oh, and electricity does catch fire, or rather it’s storage medium can. (HuffPo, really? Yeesh, I need to take a shower). And don’t forget the recent 787 experiences not to mention the occasional burning pants cell phone or laptop.
Matt’s right that it’s a silly distraction to dwell on the mass of electrons (or EM waves) vs. atoms. The other criticisms of H2 energy density and storage are legitimate, so why dilute from them with these side points?
There’s no such thing as a happy greenie.
Imagine their complaints if we sucked up our precious oceans to split H2O. Then they’d complain there’d be too much left over oxygen, causing wildfires.
I’m surprised they’re not complaining about us burning up oxygen with fossil fuels. Or maybe they’re too dumb to think of that one, much like sequestering CO2 is like suffocating plants that they haven’t thought of either, although they learned about photosynthesis in school. Dumb.
Best to leave the troglodytes behind while the rest of us get on with exploring the Universe.
Eli Rabett says:
July 1, 2013 at 5:23 pm
Goodness, Josh, miss the point much?
The point I was making is that because there is no drillable store of free hydrogen, because hydrogen is bound up in compounds by strong bonds, it is NOT an energy source. It takes more energy to break hydrogen free than you get back when you burn it. Not a source of energy in any sense of the word. Not even when you generate it “via low intensity power sources”. It’s just an energy transportation system.
And no, this is not “true of just about everything else”. It’s not true of any practical energy source. That is the definition of an energy source, that it contains more usable energy than was required to drill or mine it. That’s what the “source” part means.
And yes, this fact is designed to encourage the reader in a direction, but not in some sneaky way as you imply in your usual snarky manner.
It is designed to encourage the reader to notice that hydrogen is only a way to transport energy, not a source of energy, and that’s hardly an underhanded trick of any kind … and although I see that in your case I failed spectacularly, most people seemed to get the message without any problem at all.
Perhaps you might check your glasses, all that carrot-eating doesn’t seem to be helping your reading comprehension …
w.
Tsk Tsk says:
July 1, 2013 at 8:01 pm
Um … er … we do burn them, although often not at the source for various reasons (availability of cooling water, distribution of sources over a large area, transportation, land issues, the issue of power plant siting is complex). However, there are many, many power plants located at or very near the source.
As to whether it’s easier to move molecules than electrons, how about we test it. You send an express mail expedited delivery letter to say London, I’ll send an email, and we’ll see which one is easier, faster, and cheaper to deliver.
Why do you think that the telephone and the telegraph were invented? Why did the Pony Express go out of business? Because electrons move faster than molecules.
I fail to see why this issue seems so contentious. Are you seriously claiming it’s easier to move a letter around the planet than an email? Lets have a different race. I’ll move a kilowatt of energy fifty miles by electricity, and you move the same kilowatt fifty miles in a pipeline. Or a truck. Or a coal barge. Or a tanker.
Bet I get there first, for a simple reason … it’s far easier to move electrons than molecules.
w.
PS—Your screen name is odious. It puts an unpleasant pall over your communications, and true to your screen name, your tone is that you are scolding me for my transgressions. I’d change the name immediately, as well as the tone, but that’s just me …
[UPDATE] From Google, with the search term “define:”tsk tsk”
Is that really the message you want to send, that you are here to disapprove and tell us you are annoyed? Doesn’t exactly invite polite conversation …
I seem to remember from my materials science class the problem of metal fatigue caused by interstitial migration of hydrogen atoms. I think the term was hydrogen cracking or perosity, making it rather unsuitable for engines. Decent for Fuel Cells though as long as its clean.
I remember when Ford did their test drive across America with the “Think” car nearly 20 years ago. A team of engineers supported by a tanker of hydrogen were used to make the trip. What a colossal waste of time and money. All the policy people turned out in droves to witness their toy holy grail.
I always figured that if we could get CNG to take off in a meaningful way at 3600 psi with no reforming, the problems would be solved. H2 at 10000 psi with total steam reforming and mechanical cooling for a complete fill could be done but never as cost effectively as CNG.
Not saying that CNG is a panacea, but just a great deal better than H2 will ever be.
There is an old show called “One Step Beyond” that had an episode entitled “Where Are You?” in which the second half has a man showing up with a tablet that would allow you to use water to operate your vehicles.
One comment stands out, “Electrolysis is all you need. Water is made of the same stuff as rocket fuel…Hydrogen and Oxygen. Develop a tablet that quickly and efficiently separates those two substances and segregates them internally, then recombines in the engine in proper proportions. Yes, this is possible, folks!” Of course several more indicate a governmental/corporate conspiracy keeps this all under wraps.
Willis, great essay. How do I know this? By how your detractors fumble and stumble and behave like Keystone Kops (happy/sad/ironic metaphorical coincidence there) in their headlong rush to expose their own lack of research on the topic. Like Olaf says above, there is no such thing as a happy greenie…they are too busy being unhappy misanthropes to sit down and REMEDY their own unhappiness….by getting an education.
Thanks for the entertaining responses.
tumetuestumefaisdubien1 says:
July 1, 2013 at 4:45 pm
“Just btw. if you would transport by a conventional 2 meter diameter pipeline the hydrogen at 30 bar at a speed of say 50 meters/second, you anyway would get through just 31 GW. For same task you would need 3phase/3mount 2620 mm^2 cross-section cables (~35mm diameter for idea, although such cables aren’t in use and it would be made rather by several paralel lines using thiner cables) + zero cable at 440 000 kV electric power line. Such a power line would still fit in the 100 meter corridor “
—
Thank you for doing the math, but do you really think that it is possible to fit a 31 GW line, which is 50% more than the installation of the world’s largest power plant, three Gorges, into a 100 meter corridor?
However, what I had in mind was even bigger lines. Imagine that half of Europe’s energy consumption were to be produced from solar cells in Sahara. It’s doable, and it would require a negligible part of the desert. That part could even be a popular place to live if the installations were made in the right way to create shadows and cooler places in the desert.
The surplus energy produced during daytime has to be stored, and hydrogen may be a good alternative for that. The power lines required would need to have a total capacity in the magnitude of 1 TW, and then hydrogen pipes could be a good alternative.
There is another reason for using water (Liquid) for testing pressure vessels, it preserves the point of failure rather than blasting the vessel and everything around it to bits. The most famous use of such testing, AFAIK, was the BAC Comet in the 1950’s. The plane, except wings and tail, was submerge in a purpose built tank. The interior was filled with water and pressurised to failure point, preserving the damage.
Tangential comment on hydrogen storage density. Yes, although it is counter intuitive, mixing other stuff with Hydrogen lets you cram more hydrogen into the same space than using pure hydrogen. Lots of different reasons and ways to explain, I’ll just hit some.
In gases, there are the same number of gas molecules in any volume, so one liter of CH4 has as many molecules, and twice as much hydrogen, as a liter of H2. Of course, you have to break the CH bonds to burn the methane, so the energy per H released is a bit less, but you get more H (and you can also burn the C) per liter. True for any pressure until the you get liquid or solid.
In liquid, the individual molecules are generically attracted to each other so they stick close together instead of bouncing of the walls like a gas. But they are in constant motion, and need “elbow room”. The more attracted they are to each other, the tighter they pack. In solids, the molecules (or individual building units) take up relatively fixed positions in large organized groups.
Hydrogen as a molecule is small, but it takes far less space as an ion in a grid. (Most of the size of an atom is in its electron orbitals, an H+ ion is just a bare proton, it has no electron cloud at all) So as a hydride, you can get many H+ hanging around a heavy atom with a small tight electron cloud.
Even more density is obtained in metallic lattices. Solid metals have an extended “sea” of electrons instead of separate outer orbital shells, and then tightly held inner electron shells. Part of the hydrogen containment problem is the H2 can break up, add the electrons to the communal “sea”, and the two protons can pinball through the empty spaces. Eventually, a proton will either wander out (and usually take an electron back) or run into something that will capture it. (hence leaks and hydrogen embrittlement). With just the right spacing, you can dissolve many more atoms of hydrogen as H+ and e- than would fit in the same volume as H2 molecules, despite having to fit all the metal atoms in too. Too bad that the best are platinum group metals so, as observed in prior comments, your “gas tank” weighs half a ton and costs 15 million dollars.
Pons & Fleischmann of cold fusion infamy were investigating how the forces that permitted the increased density of the protons would affect atomic fusion potentials. After all, since the protons are closer together to start with, it should be easy (or easier anyway) to push them the rest of the way together. So far, we’re still the same 20 years away from fusion we were 20 years ago.
Willis, you missed one important property of hydrogen in addition to all the correct things you mentioned, which limits its use in the often proposed hydrogen economy.
Pumping anything, gases or liquids, through pipelines requires energy. And for every medium there is a length of the pipeline, where the energy required for transportation is equal to the energy delivered. I don’t have the exact data at hand, but for the transportation of natural gas, which is mostly methane, this lenght is ~1000 miles, while for hydrogen this is closer to only 100miles!
This is not a problem when the hydrogen is used as a raw material, as in the chemical industry (it only means higher costs), but when ENERGY is the thing to transport, then a pipeline quickly fails.
Willis,
your assumption that liquid hydrogen is the densest form of hydrogen is not true. There are examples of metal hydrides and chemical hydrides which offer higher hydrogen density, both per volume and per weight. I studied that in detail during my fuel cell activities in industry. Some public data can be found in the DOE program, e.g. this report of storage for fuel cell use in cars (pdf):
http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDQQFjAA&url=http%3A%2F%2Fwww.hydrogen.energy.gov%2Fpdfs%2Fprogress09%2Fiv_0_hydrogen_storage_overview.pdf&ei=-qPSUaTMPMSftAayxoDYCg&usg=AFQjCNEgWGLUXXdy-KfWRttrjRxu68N66Q&bvm=bv.48705608,d.Yms
Figures 3 and 4 (pages 392/4) tell the story.
However, fig 4 tells of an additional caveat to consider: not only have to get H into the (metal) matrix, you also have to get it off! And if this requires temperatures higher than available in the automobile, then it is not an option, as it would require to burn H to generate the temperature, which reduces the effective energy storage density.
But, do you know which easily available 3 compounds exceed hydrogen density of Liquid Hydrogen by a factor of 2 for gavimetric and a factor of 3 by volumetric density, and even the DOE Ultimate target? It is Methanol, Propane and Butane! All three have about 10wt% and 100g/l H. Methanol is liquid at room temperature, and the latter two, known as used e.g. for gas barbecue grills, are liquid at moderate compression (10 – 30 bar).
Therefore, the best “Hydrogen” car running on a fuel cell, powering an electric motor would be using those hydrocarbons! Of course, now it needs to have a reformer, a system which can extract the H out of the Propane/Butane/Methanol, on board too. Technically not a major hurdle, but currently too expensive.
Though this seems to be technically AND energetically feasible, I don’t expect it to happen, as the carbon in those 3 liquids will of course be converted to CO2 by the reformer, and we all know that CO2 is a poison/sarc.
What I don’t like is the deliberate lies and deception. Transport for London is STILL putting out the Green propaganda that their hydrogen busses are emissions free.
http://www.tfl.gov.uk/corporate/projectsandschemes/8444.aspx
But what they will not tell the public is that their hysdrogen comes from the gas reforming method, and so these busses are actually fossil fuelled. But since the hydrogen cycle is about 30% as efficient as a diesel bus, they put out even more emissions than a standard bus. Worse than that, the hydrogen generator is in East London, and so the emissions (including CO2) is being pumped out in East London.
So much for these hydrogen busses being clean….
jkanders says:
July 1, 2013 at 11:54 pm
“The surplus energy produced during daytime has to be stored, and hydrogen may be a good alternative for that. The power lines required would need to have a total capacity in the magnitude of 1 TW, and then hydrogen pipes could be a good alternative.
For local energy storage the hydrogen/oxygen electrolytic splitting – likely with high temperature electrolysis, where most of the energy would be provided as solar heat (- best for making high temperatures fully clean: sometimes I travel to Andorra through Pyrenees-Catalanes parc and on the way near Font Romeu there I always pass and admire the two solar furnaces there) not electricity – electrolysis consumes much less energy, when the water is overheated – and then burning again (I don’t think in such case you split by >1TW electricity the water to hydrogen and oxygen by hot electrolysis and then burning it back you would like to burn then the hydrogen with air, creating the variety of toxic pollutants with the atmospheric nitrogen and carbon you would need then get rid of using huge catalytic converters) maybe could be useful if you overcome the obvious problems with the burning hydrogen with oxygen (very high temperature, wide explosive mix ratio range). But I still don’t see a point why to transport all that hydrogen from Sahara to Europe, when for example for the 1TW – you would need at the 440 kVolt/2272 kAmperes band just twelve parallel 3 phasex1vein 150mm cable lines – which although being huge powerlink never built anywhere to my knowledge I still find way more viable than a 1TW-in-pressurized-hydrogen pipeline from Sahara to Europe.
Even high tension cables you can lay on seabed without much fear, but I doubt you can lay there a high pressure pipelines (-for 1TW you definitely wouldn’t be able to make it through using one) – Mediteranian between Sahara and Europe is active seismic region – there are two pipelines through mediteranian to Sicily, but they’re conventional for oil and gas and even that was quite a technological feat.
Btw: The energy consumption of EU now is 1900 mio toe from which 79% is covered by fossil fuels, 12% by 2-3 gen. nuclear, rest by renewables, mainly hydro. So gradually you would need >2.5TW in next much less than 100 years to cover the fossil fuels and U-235 depletion -if we assume the consumption wil not rise anymore. That would need ~size of Tunisia solar plant – and esecially if you would want to transport the energy using the hydrogen with losses it brings into the chain.
My opinion is – and I expressed it here already – that much better than do megalomaniac projects as “Sahara powering Europe by solar” (which I find rather unviable for variety of political, economic and even environmental reasons – how to recycle Tunisia size solar plant when its lifespan is over?!…) that way is more to go off grid for example using local scallable 4th generation Thorium based plants, with several orders of magnitude higher power generation intensity than any contemporary even cutting edge power generating technology can ever achieve. This would largely avoid the extensive fuel transportation and power networks, which besides losses are vulnerable to variety of threats from storms to terrorism.
Frankly, I don’t believe for a second anybody would be able to fully susbstitute for fast depleting fossil fuels in the given deadline (until ~2050 – optimistic general fossil peak prediction) using anything else than nuclear fission technologies of the 4th generation (even D-T fusion definitely will not be available then). Moreover I think the Sahara would be much better off if reforested (forests destroyed there in ancient times) than planted with statesize solar megaplants to feed Europe with energy, which can be obtained on the spot by much less expensive, less resources demanding and versatile technologies without need of high distance powerlines for anything else than backupbone, nevertheless much more likely giving the needed energy production potential.
tumetuestumefaisdubien1 says:
July 2, 2013 at 4:36 am
Many good points there my friend, you may be right concerning power lines, and I may also, future will show. But let me comment on one point:
“Moreover I think the Sahara would be much better off if reforested (forests destroyed there in ancient times) than planted with statesize solar megaplants to feed Europe with energy, which can be obtained on the spot by much less expensive, less resources demanding and versatile technologies”
To reforest Sahara would probably need a climate change which brings much more rein to the region, and I don’t think that is within reach of our technology.
But we can “reforest” a part of Sahara with a type of Solar cell “trees”. This type of constructions does not need to be negative to the local environment in the desert. It can be a highly desirable change. Cool shadows and a surplus of local cheap energy can vitalize the region and an attractive region for living can be created.
@Codetech
Stanford University has a very wellsupported paper that identifies a baseload capability for interconnected wind farms.
True, wind is not blowing all the time in any particular place. However, it does blow all the time, somewhere — and that somewhere is more locally consistent than the uninformed may think.
With almost decade old tech, Stanford identifies a 33% Windfarm Nameplate Capacity as an average baseload capability. e.g. a set of interconnected windfarms with a Nameplate capacity of 3000 MW – provides a dependable baseload capability of 999MW – continuous.
Enjoy an informative read.
“It was found that an average of 33% and a maximum
of 47% of yearly averaged wind power from interconnected farms can be used as reliable, baseload electric
power.”
http://www.stanford.edu/group/efmh/winds/aj07_jamc.pdf
Of course that does not change the fact that hydrogen has too many warts to be used as a medium for bulk energy exchange over distance.