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.
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About 10-12 years ago, I talked to a guy from the Electric Power Research Institute (EPRI). At that time, there was a great deal of interest in proton exchange membrane (PEM) fuel cells, which use hydrogen for fuel. A lot of people were promoting these things as the next great invention for producing electricity for a multitude of applications including transportation. Efforts were focused on converting hydrocarbon fuels into hydrogen but the dirty little secret was that in addition to producing CO2, such processes do not provide chemically pure hydrogen. Thus, when the impure hydrogen was “burned” by the fuel cell, the contaminants tended to “poison” (disable) the catalysts so the cell lost efficiency and ultimately failed. EPRI was conducting research (perhaps just a paper study) to see whether it was feasible to run nuke plants at 100% power 24/7 and use the excess power during off-peak hours to electrolyse water into hydrogen and oxygen. Since electrolysis is a process that uses electricity, the grid could be used to power hydrogen production equipment that is distributed to be near the points where needed, thus reducing transportation problems.
@ur momisugly jdallen
Your link could hardly be more dated and obsolete. “Wind three times cheaper than nuclear power” obviously depends upon the outrageously nonsensical figure quoted by anti-nuclear nerds
that a 1000 MW plant would cost over $15 billion. And the claim that “no one is interested in nuclear energy” could hardly be more inaccurate in today’s world, as opposed to the long ago
world of 2004, when preposterously idiotic claims were being made for solar and wind power by their supporters,accompanied by ridiculous claims about the cost of nuclear, which is almost 4 times the actual cost today, after 10 years of inflation. Wind power is pactically defunct – Britain is building nuclear,not offshore (o onshore) wind anymore, despite the large volume of winds available. Lovin’s claim of 30 to 35 % capacity for wind turbines is way above the average, and nuclear plants average roughly 90% capacity, usually 4 times that of wind. Wind power we now know , based on actual experience costs at least 3 times nuclear Nuclear operating costs became the cheapest form of energy production in 1999. Lovins is, quite frankly, nothing more than hot air. His “solution” to what is now a non-problem (energy) is simply “use less, drive less, or the same old environmentalist crap. Lovins completely missed the fact that we have plenty of energy – just the energy contained in our nuclear wastes (which can be burned by a fast reactor or Thorium reactor) could provide all the electricity this country needs for the next 1000 years.
And I must point out the enormous land waste of solar – a solar farm large enough to produce the same amount of electricity as a typical modern 1500 MW nuclear reactor would require 80,000
acres of land.
I also should point out the often irrelevant issue of energy per pound, volume, etc in comparing energy sources. The electrons stored in an electric car weigh nothing, yet electric cars weigh more that gas powered vehicles. Obviously the reason is because the storage medium (batteries) weigh a lot – the Tesla Model S battery pack weighs nearly 1000 pounds. Comparing energy per pound/volume is also misleading – e…g. the energy in a gallon of gasoline is in large measure “wasted energy” as it is released as heat. Some can be used to heat the car in cold weather, but energy must be expended (running the water pump, fan) to get rid of most of it in the winter and all of it in the summer.
I would like to add, that most rockets that send stuff into space don’t use hydrogen for the first stage. They usually use RP-1 or equivalent, which is a refined kerosene ( a lot not all lol). Second stage usually is hydrogen.
So even rocket scientists know hydrogen is limited. Hence why I am planning to build my rocket with kero instead of hydrogen.
jdallen says:
July 1, 2013 at 1:35 am
“Cheap, specious shot, Mr. Watt.”
I don’t think the article is a “cheap, specious shot”. I think it is quite sober overview of some of the hydrogen prohibitive disadvantages. I just have one objection – Anthony writes:
“And that means that if someone want 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.”
There actually is the material and it was discovered already in prehistory by nature itself. The material is called carbon. Together with the hydrogen it forms so called hydrocarbons.
For instance the most simple one is methane CH4, which also happens to to be the most energy dense common hydrocarbon and although having 2.6 times less energy density per kilogram in comparison with liquid hydrogen -it is actually an energy source, chief compound found in natgas (also found in oil and coal), not just energy transport medium -it can be stored compressed at 250 bar without cryogenics, not at 690 -it is liquid at -160 C not -253 C…
Then we have a little bit complicated ones propane and butane with even little bit less energy density 2.9 times less than liquid hydrogen, and liquids as diesel (mixture of mainly paraffins, napthalenes and alkylbenzenes) with energy density 3 times less than liquid hydrogen -can be stored in unpressurized container as it has low volatility, simmilar density per kilogram but little less per liter has gasoline (mix of various C4-C12 hydrocarbons), as it is more volatile than diesel it should be stored in airtight containers. etc.
I think Anhony is very right.
The hydrogen is not much viable.
It is even dubious if it is a good fuel for the applications where the energy density is absolute priority. Which I think was chiefly the case of fuel for the past generations of the rockets – Even in rocketry the hydrogen was largely abandoned for many disadvantages, which overweighted the only advantage – the energy density of hydrogen if liquid or compressed at very high pressure.
Why not viable? Besides the technicalities making hydrogen very difficult to handle you need energy to produce it – and if one would have the energy, there are now technologies available able to synthesize almost anything from the hydrocarbon realm including easy to handle liquid fuels as diesel, gasoline and kerosene.
So why hydrogen? – which is very difficult and costly to handle and potentially very dangerous?
The question is rather what we do when the reserves of fossil hydrocarbons (the magic stuff carbon which binds the hydrogen) as energy source will be depleted. Where we get the resources of the huge energy which runs our technological civilization?
It is not much time left…
Even with the shales the total hydrocarbon reserves are there for way less than century at the curent levels of consumption and my opinion after thorough sonsideration of the subject is that the general hydrocarbon fossil peak will occur before 2050! (my estimation given the current proven and likely reserves, including shales, and and on the other hand trends of consumption is 2045 plusminus 5 years) If the fossil resources will be not fully substituted for until then, the technological civilization as we know it with economy based on growth will cease to exist. A system can’t run without energy and the function of system decay in case the system has less energy readily available than needed to sustain itself is exponential. This is much more actual threat to mankind than a CAGW.
I’ll add that not even the currently used nuclear technologies, with dubious safety record, based chiefly on fission of the Uranium 235 in light water reactors to produce steam for turbines will save us – there’s not much U-235 left, it is very scarce and the current technologies using it are very inefficient making practically available as electricity only up to 0.2% energy contained if conversion efficiency is taken into account. The remaining reseves of U-235 are barely enough for existing nuclear powerplants until the end of their lifetime. It is true there’s quite alot of Uranium in sea water, but the cost to extract it is 10 fold than from conventional resources.
Even if we would find the way how to safely and inexpensibly handle the hydrogen, where’s the energy needed to produce it?
My opinion is that the energy is in one element, much more abundant than Uranium-235. In the naturally occuring Thorium 232. Currently it is the “waste” from mining rare earths.
The technology how to use it most efficiently was researched in 1950-60s in USA under the programme MSRE in Oak Ridge National Laboratory and demonstrated viable with research reactor already in 1969. Then abandoned mainly for political reasons. Recently it gains again steam, although still very very modestly.
According to my inside informations from the researchers the amount of money which would be needed to develop this into fully commercially viable technology is in order of ten billion USD. That divided is less than 1 day living cost per person even for the poorer half of the mankind – to finance it and have it. If we would divide the sum only between the inhabitants of the rich west, it would be then way less than 100$ one should contribute to have energy resource technology cappable to run this civilization for at very least thousands of years given the proven Thorium reserves. Moreover the thechnology would produce “by the way” many other things than electricity – Pu-238 and Sr-90 for longlasting nuclear bateries for space research, rare isotopes as Molybdenum-99 for medical purposes, xenon for lighting, rhodium, ruthenium and palladium for electronics and catalytic converters, neodymium for strong magnets, abundance of desalinated water for agriculture where scarce, energy for hydrocarbon fuel synthesis, energy for fertilizer production, and last but not least the energy for the water electrolysis and thus oxygen and the discussed hydrogen production.
I know, you ask, why on earth when they waste so much money everywhere all the time for nonsenses, including “carbon pollution” fighting, why we already don’t have it?
A lack of political will perhaps? Too many greens with confused antinuclear stances there for decades? Frankly, I don’t really know. But rarely I agree with J. Hansen and I think he is right it is a disgrace.
If I go back to the hydrogen there are other isotopes of it: Deuterium and tritium. Deuterium is found in the nature and is quite very abundant – 0.0312%mass of all hydrogen on our planet is Deuterium. It can be together with the Tritium used in the nuclear fusion reactors and the energy density of their appropriate mix then would be 2.6 million times higher per kilogram than of the liquid hydrogen. Problem is that Tritium is except traces not found in the nature and again must be produced in the nuclear reactors. Also, unlike the MSRE technology, despite huge amounts of money invested in the fusion technology development, sober estimates don’t expect it to be commercially available sooner than in several decades. (Not speaking about Deuterium-Deuterium fusion, which is even much harder to achieve.) That could be for us all too late.
Matt:
A number of years ago, there was a guy who argued that we should use hydrazine as a primary propellant for orbital rockets (not just for final stages and smaller engines).
When I pointed out that it was a nasty, horrible substance to work with, and would be nearly impossible to manage in thousand ton lots, he just handwaved the problems, claiming it was all just “engineering issues.” My assumption was that he didn’t care, since he wasn’t going to be the person handling it…
Kajajuk says:
July 1, 2013 at 5:18 am
Did you read what you said before you posted it?? It makes absolutely no sense!
And that is the problem w/ watermelons; thinking in silos with no connection between the silos leads to absurd beliefs that have no basis’ in the real world.
BC
I might also point out how ludicrous burning H2 to produce water and permanently removing oxygen from the biosphere actually is, a problem which can’t be overcome unless the H2 is source from water electrolysis, an incredibly inefficient process.
ps there is another potentially useful Hydrogen carrier for fuel cells that is ammonium (NH4) in its various forms, for example I’m told kg for kg you can get a bit of energy out of ammonium nitrate.
Willis, Another excellent article that explains the properties and myths of hydrogen that impact it’s usefulness as a clean fuel.
As one who has designed and worked on numerous H2 plants over a number of years, I can confirm the accuracy of your post on the challenges of handling H2. Most H2 is manufactured in a high temperature reforming process using natural gas as a feedstock. Steam and natural gas are fed into tubes inside a high temperature furnace. CO2 is a large byproduct of manufacturing hydrogen in this process so the myth that burning H2 is clean neglects this fact.
Virtually every refinery in the world uses hydrogen plants since H2 is used extensively to remove sulfur and upgrade heavy oils at high pressures and temperatures. Massive amounts of H2 are used in this upgrading of crude oils. Also hydrogen is extensively used in Chemical plants in the manufacture of the many plastics and products that we use everyday.
I remember the foolishness of our MSM and government several years ago touting the clean H2 cars that we would all be driving, knowing full well how we manufacture large quantities of H2 from natural gas.
Willis is correct, H2 is not an energy source, but it does have important applications in clean fossil fuels and chemical products. By the way the so called bio fuels are also dirty and require extensive clean up using H2. There is lots of sulfur in wood and most of the other cellulosic biofuel feedstocks that needs to be removed.
When will the MSM do it’s homework and stop misleading us??
cirby:
I tend to find when the person doesn’t have to handle something they don’t seem to care. Hydrazine is only good anyway for small orbital movements (which I am sure you are aware).
I do find after starting this rocket project a lot of people seem to have no idea. Keep asking me where I will get Hydrogen from, when you explain its better to use a fossil fuel, aka kero. They tend to go weird. Then crap on about it being dirty and I need to use a ‘clean’ fuel.
Remember when they were touting hydrogen to replace gasoline in cars a few years ago? At the time I wondered where they would get all that hydrogen. That all faded away, as reality caught up with idealism.
@jdallen
If the author of your Harvard Mag article had ridden his bicycle about a mile down the road he could have talked to some real engineers about the realities of a hydrogen economy before he wrote his article.
Thanks again Willis!
I once, not too long ago actually, debated with someone who was a carbon dioxide and methane hater, with regards to AGW and climate change, who told me methane had “4 carbons”, I kid you not!
Nice piece Willis.
You’ve hit the nail squarely on the gad as usual.
Jdallen, you really don’t know the first thing about it, do you? Mind you, it would seem you omitted to read the article – and if you did, you didn’t remotely begin to understand it.
Shoo!
There is one way in which hydrogen may become an integral part of energy generation – see
http://arxiv.org/abs/1305.3913v3
On page 23 of the report in the above link is the same diagram as in the post by Willis (whose posts I always enjoy reading).
The scepticism at the time of Fleischmann and Pons announcement of cold fusion in 1989 one can understand. Using the sort of dirty tricks (data manipulation), “consensus” and ad hominem attacks, familiar to readers of this blog, was enough to drive this area of investigation well away from main stream science. However, there are still men with integrity who are prepared to go against the accepted “settled” science and support work on this phenomenon. Brian Josephson (Cambridge) and Rob Duncan (Missouri) – a former sceptic – are examples. There are also business men like Rossi who, admittedly with a dubious past, have recognised an opportunity.
Perhaps hydrogen and nickel may indeed be a source of future energy, but in a completely different way from the “hydrogen powered future” referred to in the first comment.
@jdallen
You cited a blog nearly 9 years old. In nearly a decade, nothing has really advanced in the ‘hydrogen economy,’ has it? Otherwise,you would quote something not so out-of-date.
Where are the hydrogen power stations? Where are the hydrogen-powered cars? Heck, where’s my flying car?
Seriously, you have to learn to tell the difference between speculative, Utopian fantasy and the real world, Myself, I love watching those Ancient Astronauts ‘documentaries’ on the History Channel, but I know they are just wild-eyed speculation without any basis upon verifiable fact.
I enjoy the immensely convoluted imaginings of the likes of Mr J D “cheap shot” Allen and his greeny chums but I wonder why they continue to speculate about all these pointless sources of energy when we already have abundant cheap energy available. We have nuclear to provide electricity. France does it very well and has done safely and cheaply for 50 years. We are developing new nuclear technology all the time. We can now burn the waste from the old “bomb” plants. We have nuclear powered ships ( Nimitz class) which could provide most of our deep ocean transport if applied to cargo and tankers. We have small modular nuclear power plants such as the Westinghouse AP1000 which can be built in 36 months, (without allowing for bureaucratic shenanigans) and deliver 1GWe close to the demand area. We have enough gas to provide heating, which is probably it’s most efficient use, rather than converting it to electricity, and when it runs out, if ever, we can heat with nuclear electricity. We have enough oil for road, rail and air transport and if it runs out we can manufacture liquid fuel from coal as the Germans did in WW2. A better use of coal if we do not have to waste it on generating electricity.
I struggle hard to find a problem in any of this relatively simple and already applicable scenario. If I progress this 100 years into the future, assuming that mankind has not been removed by the Yosemite or Canary Island super volcanos or by a huge asteroid strike, then my words will still apply. We will have even more efficient nuclear, possibly liquid thorium, ( fusion will still be twenty years in the future) We will have much better insulation and building practices, taking the pressure off gas consumption and making it more economical to heat and cool with electricity. We will have marginally more efficient internal combustion engines but possibly better use will be made of road trains, rail trains and larger air liners. (A useful battery/electric car will still be twenty years in the future). There will still be massive amounts of coal available for liquid fuels. Go forward another 100 years and it will be much the same. People will still not be wearing lycra jumpsuits in the street and eating soylent green. So, I ask myself, what is the problem? I must be too stupid to see it!
bobl says:
July 1, 2013 at 6:24 am
I’m told kg for kg you can get a bit of energy out of ammonium nitrate.
Yes, especially if that energy is released in a fraction of a second, as happened in a French fertilizer factory a few years ago, killing a lot of people in the factory and far beyond… Also the prefered energy storage of Anders Breivik in Oslo, killing 6 people with a car bomb filled with that material. And of Timothy McVeigh for the Oklahoma City bombing killing 168 people…
On second thought, I would prefer hydrogen, seems somewhat safer to me…
Actually, Patrick, in the industrial gas business it is quite common to do pneumatic pressure testing because we don’t want any residual water in the system. When it’s done, there is a safety blast radius observed.
I have heard (sounds counter intuitive) that Metal hydrides can store more hydrogen per cubic foot than the density of liquid hydrogen. The problem is the “metal” part of metal hydride… its heavy! For stationary sources its OK, weight is not a problem for most stationary sources. You can treat a hydrogen fuel cell with its fuel like a battery (that’s what it really is).
There seems to be alot of expertise in the comments of this blog. I have a question. What about spliting (cracking) ammonia to get hydorgen (NH4).
Thanks Willis, I like the electrons vs. molecules analogy.
Eric Worrall says: July 1, 2013 at 2:09 am
[…]
I tell you what – I’ll give the hydrogen a go, if someone pays for my super insulated tropical vivarium where I can grow bananas in Colorado.
I know of a greenhouse with a passionfruit tree at 7000+ ft on Basalt Mountain, Basalt CO. No extraneous heating is required, the summer heat is stored in the ground, literally the earth floor. I did a spread sheet for the heat/mass storage contingent on average temperatures, altitude and humidity for this guy. He builds commercial greenhouses that use little to no artificial heating with this method.
“PiperPaul says:
July 1, 2013 at 7:17 am
Actually, Patrick, in the industrial gas business it is quite common to do pneumatic pressure testing because we don’t want any residual water in the system. When it’s done, there is a safety blast radius observed.”
You will find many of the components, especially large capacity tanks, are water pressure tested before installation. It’s the safest test as there is no “blast radius” risk. That’s my point. Post installation is a different ball game!
The problem with metal hydride storage for hydrogen gas is that it takes high temperatures to get the hydrogen out of the hydride lattice after storage – on the order of 300C.
The weight-to-storage and cost-per-liter issues are pretty much impossible for vehicles, and also daunting for industrial plant uses. When you look up the available ones for lab use, you start seeing 2000:1 ratios for weight/storage…
One application I found that might work out: forklifts and lift trucks. Due to the need for very heavy vehicles, having a two-ton hydride tank on a 1000-pound-capacity forklift makes a certain amount of sense.
When people talk about a hydrogen economy, all they’re really talking about is hydrogen for transportation and maybe for energy storage to balance out the variability of renewables.
For both of these functions, methane is infinitely more practical. We can use methane from the ground for now because it is cheap and make our own from CO2 and Water later.
Kajajuk says:
July 1, 2013 at 5:18 am
“Hydrogen would be a viable option as a “non point” energy source i.e. convert excess electrical production from all sources into hydrogen instead of sending the excess into the ground. But that would require a government/industry tuned towards the public good (or long term residual profits) and less so to corporate profits…good luck with THAT.”
You mean we could solve all kinds of problems with money losing businesses? Hey, how about you occupy a larger island in the carribean just next to Florida and demonstrate it.
Wait…