H2? Oh! New water-splitting technique pushes progress of green hydrogen Researchers in Spain have uncovered a new approach to producing hydrogen via water splitting which could help overcome some of the drawbacks to this promising alternative fuel source. In a study published in Nature Energy, Valencia University researcher José Manuel Serra, professor José M Catalá-Civera, and their colleagues …
Yep, and even ignoring safety concerns hydrogen is a bit of a faff to store, transport and transfer.
Some folk are looking at using amonia (one nitrogen and three hydrogen atoms) as an energy dense fuel - again using catalysts and renewable power sources:
https://www.sciencemag.org/news/2018/07/ammonia-renewable-fuel-made-sun-air-and-water-could-power-globe-without-carbon
One of them already has 18 atoms of hydrogen in the mix, and can easily capture and release more, but requires catalyst action to use. However that catalyst could be put in the car and used with the carrier directly, then the by product drained into another tank. Sorry, I can't remember the name of this wonder fluid, but I think toluene is one of the ingredients. It can be stored at room temperature and piped just like oil to the gas stations. Ammonia has to be kept at 300 psi, I believe and under some cold state with insulation also; the alternative is much better.
However once you get pure hydrogen it can be made into what is commonly called "blue crude", using a process the Germans discovered in WW2, so that would probably be even more practical - plus it works well in aircraft jets, and internal combustion engines - no battery needed. I read an article that said the carbon can be absorbed directly from the air, so it would be carbon neutral ( as long as the original H2 manufacturing process doesn't burn fossil fuel to power the making of hydrogen in the 1st place).
"The promise of hydrogen fuel cell powered cars, is that the garages can generate their own hydrogen in situ"
Instead of using half of that energy to directly charge battery and then use electric motor. Right.
Doesn't literally make any sense, H2 is just wasting energy in that scenario. Not to add enormous amount of weight and cooling systems etc. into car. At least as much as modern electric battery.
Zero benefits fom H2, just huge amount of cost.
TBF you can re-use most of the infrastructure that is used for Petrol and Diesel, adding csome more high pressure elements, it becomes pretty much a flamable liquid, but if you get it wrong cf hindenburg ----->
H2 is a good transport and storage medium for electricity, and its a lot better for the environment than Li-ion cells.
" you can re-use most of the infrastructure that is used for Petrol and Diesel, adding csome more high pressure elements"
No you can't. Hydrogen needs to be stored at -170C with major pressure (300bar or so) and *none* of the existing infra can handle that.
"H2 is a good transport and storage medium for electricity, and its a lot better for the environment than Li-ion cells."
It's literally *horrible* medium for electricity: Energy density is only 10% of diesel and it *leaks*.
H2 itself might be better than li-ion but generating, storing and transporting it is really a PITA and li-ion wins 6-0 in any rational discussion where people have the basic idea what kind of stuff H2 is to store and transport.
Basic rule is that you don't. It's as simple as that. Using electricity to make H2 to drive a car with that H2 is outright madness: Just *storing* H2 into car weights and costs more than battery for similar range.
Not quite. Hydrogen gas only has a molecular weight of 2. It's practically the smallest thing that exists naturally. Think about how tough it is to reliably store helium (atomic weight 4) because of its tendency to seep through even the tiniest holes; hydrogen is even worse than that. Containment and leaking have always been the biggest problems with hydrogen gas.
Such Hydrogen leakage is too small to pose any serious risk in most applications. And if there is a major leak, gasoline is far more likely to pose a problem than Hydrogen. It's actually not that easy to get Hydrogen to burn or explode, gasoline on the other hand is easy, and it burns for much longer
https://www.youtube.com/watch?v=7bFJK5kU_UQ&feature=emb_err_woyt
The real issue with Hydrogen is storage density. There are number of proposed solutions, but we're still waiting for one to take off.
Such Hydrogen leakage is too small to pose any serious risk in most applications.
I think the issue is more an efficiency issue than a safety issue per se.
If there is always leakage in hydrogen storage and transportation systems due to how hard it is to contain hydrogen, how much hydrogen do you have to produce to provide a sufficient supply at the point where it is converted back into energy in, say, a car engine?
How much is lost while being stored locally at the hydrogen manufacturing plant, through the pipelines, through the transport tankers (ships, trucks, trains), while in storage at hydrogen filling stations, then in the hydrogen tanks of the vehicles using it to produce their energy?
If the loss is significant over that entire journey, then a massive amount more hydrogen will need to be generated than is used to actually produce useful work. If sufficiently efficient (in terms of energy input and other resources) and cheap production can be implemented then this is only a minor concern, but still non-trivial.
Of course, if the manufacturing phase can be made efficient enough at small scales, localities with access to sufficient local raw resources (water, energy) could produce it on-demand at such filling stations rather than needing extensive hydrogen storage and transportation systems.
I thought they fixed that issue by using activated charcoal made from chicken feathers. The AC absorbs the Hydrogen like a sponge when under pressure, but it releases it when pressure is reduced. There's another issue with Hydrogen regarding storage too. Because Hydrogen will migrate through steel, you have a phenomenon that makes steel very brittle.
The real issue with Hydrogen is storage density. There are number of proposed solutions, but we're still waiting for one to take off.
Didn't they have a solution about 80 years ago that involved storing it in giant bags of doped canvas? That took off, as I recall. And carried passengers.
Foolproof. Nothing could go wrong.
'It's actually not that easy to get Hydrogen to burn or explode, gasoline on the other hand is easy, and it burns for much longer'
That is not just inaccurate, its completely wrong.
The flammability range of Hydrogen is from 4% to 74% in air, whereas gasoline vapor is from 1.4% to 7.6% in air. In laymans terms, any concentrations outside of those parameters, even with a continuous ignition source, the mix will not burn or explode. Any mixture within that range, it will readily combust. This difference is reflected in the different hazardous area classifications both materials are given by experts who know what they are talking about and don't rely on YouTube for their risk assessments.
Clearly, Hydrogen is a far more hazardous material.
You are confusing risk brought about by outside parameters with inherent risk.
Reduce the temperature and you won't have gasoline vapor to mix to the required explosive concentration but that same change in parameter would have no effect on the H2's flammability due to its greater gaseous phase range. At a higher temperature, have a H2 or gasoline leak into an enclosed space which already has a proportion of O2 and the likelihood of H2/O2 explosive combination is far higher due to its greater flammability range.
True - as far as it goes: Hydrogen just pools under the cealing and/or tries to sneak into enclosed spaces for that bigger and better Bang. I work with some cryogenic systems providing liquid H2 for research. We do spend *A Lot* of time on EX-rated Everything, Prevention of electrostatic phenomenae, Gas Detection and Ventilation!
"Not quite. Hydrogen gas only has a molecular weight of 2. It's practically the smallest thing that exists naturally. Think about how tough it is to reliably store helium (atomic weight 4) because of its tendency to seep through even the tiniest holes; hydrogen is even worse than that."
Not even close to true. Atomic weight is almost entirely irrelevant to size. Helium, containing a full shell of electrons, is the smallest atom that exists. And that's before you remember that H2 is a molecule that contains more than one atom and is therefore significantly larger again. Hydrogen does indeed have issues with storage, but there's no need to exaggerate things with such silly claims.
"Hydrogen does indeed have issues with storage, but there's no need to exaggerate things with such silly claims."
Obviously you haven't ever tried to actually store H2, but assume everything. 2% per week is about what we can measure. That's almost as bad as helium, in very real life application (laser cutting).
Safely isnt really that much of an issue from a technology standard.
Engineers are already looking at converting wind power to hydrogen (it was via electrolysis) as a more efficient method of transferring energy from offshore to land as the %of electricity lost to power transmission can be upwards of 6% - even at very high voltages (where windfarms use step up transformers to send the power). This would open up large shallow areas of sea which are not close to land, but have more consistent wind - such as Dogger Bank and potentially floating (rather than anchored) wave and wind power. Tankers or pipelines then 'tap off' hydrogen and return it to land.
One of the problems with gaseous hydrogen is that to have decent quantities of it, it needs to be rather compressed..... and compressed Hydrogen is perhaps the molecule most prone to leaking through other materials - as well as making others brittle. Steel is one of the worst to get brittle damage - though copper pipes are almost immune, they cant handle sustained pressures and is fairly porus, so complex material engineering is going to be required....
Another problem with storing compressed hydrogen is the weight of containers that can store it safely at the sort of pressure needed to match the energy stored in a similarly sized tank of petrol or diesel. The catch is that the weight of these containers is enough that, although the energy content per litre of hydrocarbon fuel can be matched easily enough by compressing the hydrogen, the total weight of the hydrogen tankful will almost certainly be much higher than that of the same sized tank of petrol or diesel.
Result: inferior performance and load-carrying capacity of the hydrogen fuelled vehicle when compared with its diesel or petrol equivalent.
but not much lighter (if at all) when you consider hydrogen cars also have to have sizeable a battery to cope with peak loads under acceleration and inverters on top of a fuel cell stack, plumbing, extra strengthening for crash protection, high-pressure connectors for refilling and the actual storage tank with the hydrogen in it...
"But MUCH lighter than the batteries of a tesla: 480 kg"
30l hydrogren tank about 50 kilos (300bar), insulation to keep it cool 10 kilos, fridge and cooliing pipes to keep it at -170C, 20 kilos.
And what happens when your fridge runs out of electricity? *POFF* says your H2 tank. Oops.
Just to keep the H2 cool you need to have fridge running 24/7. All of that is out of range and it's still much less than what (that model) of Tesla has.
"Result: inferior performance and load-carrying capacity of the hydrogen fuelled vehicle when compared with its diesel or petrol equivalent."
No. One of my customers has just started testing a heavy vehicle for demanding applications which is powered by hydrogen fuel cells. They (v serious and competent engineers) expect it do deliver the same performance as the diesel vehicles they also build. They're developing it because their industrial customers are asking for options to reduce their carbon footprint.
Another problem with storing compressed hydrogen is the weight of containers
Isn't that a problem of scale? It would be silly to power something small like an electric bike with hydrogen because the weight of the container and fuel cell will dwarf the small quantity of hydrogen it requires. But for something like a train it should have a much better power to weight ratio than batteries of equivalent energy. The crossover is likely somewhere between "passenger car" and "semi tractor".
A proof-of-concept ran not that long ago. In that one the hydrogen was in cylinders in the coach but it would be easy enough to get them underneath or go back to the traditional locomotive format.
With all these things starting at the bigger end is often easier as size and weight is less of an issue.
Most of the diesel powered passenger trains have a crappy bus engine buzzing away under every carriage because it was "cheaper to maintain". Now for short two or three coach units it probably makes sense but for all the long distance trains it has to be less economical.
I think you have to differentiate between different types of diesel passenger trains.
There are those with diesel engines under each carriage (like the infamous Pacers in the UK), but these tend to be for lines where station platforms are short, and the length of a traction unit added to the train will reduce the capacity of the train. These trains are really busses on rails, and were even made by bus manufacturers.
If you look at most passenger trains for faster lines, then you normally have a traction unit at the front, or at both ends, (and for some trains, even in the middle). But the highest load capacity trains often are diesel-electric units, where the diesel engines run generators, and the actual motive power of the train comes from electric motors, often on the axles of the carriages. These trains normally run as a set, with the traction units and the carriages not normally being split up during the life of the train.
For freight trains, it is normal to have traction units which are both the diesel generators and the electric motors, so that the freight itself is carried on unpowered trucks. This allows the trucks to be left to be unloaded and reloaded and the traction unit used to pull another train.
An open, fogging tender of liquid hydrogen towed behind a steam engine is the future.
Of course if you simply have a second tender of liquid oxygen, then you can make your steam on demand without the boiler.
Damn heroic job being a cryo-stoker bucketing the fuel into the firebox.
The chemistry behind this is incredibly fascinating.
Kubagen's step-changing material uses Kubas binding to its patented transition metal-based Kubas Hydrogen Sponge (KHS-1) to give hydrogen storage systems which project four times the volumetric density of 700 bar incumbents at five times lower costs, making hydrogen fuel cells an attractive alternative to lithium battery technologies, especially for long haul and off grid applications.
https://www.kubagen.co.uk/
"Kubas binding to its patented transition metal-based Kubas Hydrogen Sponge 2
And, as usual, this is patented snake oil until we see it in practise.
Hydrogen, as fuel, is a promised land of snake oil peddlers.
It's so easy to swindle money from believers it's a shame, really.
"as a more efficient method of transferring energy from offshore to land as the %of electricity lost to power transmission can be upwards of 6%"
And they'll fail. If you can transport (*) any amount of H2 without losing >6%, it's a miracle. And those won't happen in real life.
*) make it, put it in a container, move it from a container to vehicle/pipe, move it to another container (for use). 2% loss at every step sums to 8%. That's very, very optimistic estimate.
"so complex material engineering is going to be required...."
Yes. We just use this wonder material which doesn't exist, and most probably *can't* exist, and *no problems at all*. H2 is *slippery beast*. And that's a *major blocker*.
Room temperature supraconductivity is *much nearer* than this and when we have that, H2 is dead on arrival: Useless and inefficient for any use.
I think you have hit on the main reason why there is so much research in recombining recovered CO2 with hydrogen back into fuel: you end up with something that comfortably sits inside the established supply chain of tank wagons and pump stations, you end up with a more regular kaboom risk and from what I remember it didn't require much adaptation of existing combustion engines.
If I recall correctly there's even a form of storage-in-fluid for cell use which renders it kaboom free and usable in electric cars, but with a need to collect the waste product to "recharge" it - again, not hard for established infrastructure but it's more involved than just re-creating fuel.
I see this as a more promising approach to electric cars - batteries has a FAR lower energy density, yet take a long time to recharge. That last fuel cell approach would basically amount to emptying a tank and refuelling, as quick as a fossile fule powered vehicle, with FAR lower risk of it self-igniting or expose fire brigade crew to dangerous events in case of an accident. Lithium fires are not fun.
"are largely obsolete after cars/trucks have gone electric."
How many new fuel stations have you seen lately?
~30 years is what the undeground tanks last and then it's refresh or demolish anyway.
Also, electric cars are and will be *very expensive*. Average car purchase here in North is 3k euros.
You don't buy *any* electric car, even very used one, with that amount. Not in long time or possibly ever.
I took up your challenge
https://www.ebay.co.uk/itm/184913871895
Nissan Leaf 2013 (63 plate), Long MOT, 4 new tyres, ready to go. cold air con.✅ See original listing
Nissan Leaf 2013 (63 plate), Long MOT, 4 new tyres, ready to go. cold air con.✅
Item Ended
Condition:Used
“Ready for use, great little runabout or commuter in town cities etc, ~50 mile range. Excellent heat ” ... Read more
Ended:02 Jul, 2021 10:27:09 BST
Price:£2,795.00
Best Offer accepted
Postage:
Free collection in person
Located in:Watchet, Washford, United Kingdom
Seller:
originalenergy
Stores ~ 900 x the volume of the Palladium cube (with a bit of silver to cure embrittlement)
However this has killed cold-fusion experimenters.
I worked with H2 experiments, we never knew if one was burning (silently) tho’ we carried H2 detectors as a guide. Burning was good, not burning but leaking was more worrying if the value headed towards the LEL ~4%[http://conference.ing.unipi.it/ichs2005/Papers/120001.pdf]
"https://afdc.energy.gov/fuels/hydrogen_basics.html
I think you have the energy density the wrong way around.
"
You think wrong. afcd is talking about kilos, but you can't store or transport kilos of H2: It's always volume.
And then all of their claims fall totally apart. Energy density for gases is measured by volume and for H2 is *really poor*.
I loved the comment from Malte Janssen of Imperial college.
I bet he would have been with the ' Too fast to breathe' crowd at the advent of the railways.
Fine, continue with developing proven technologies but don't sweep something new and innovative under the carpet because you didn't think of it.
Valencia is my local uni and they do some good outside the box thinking.
Not really: Hydrogen is not what you want for storing energy. You might use it in a fuel cell to drive something but otherwise for transport and storage virtually anything else is preferable. But the chemistry and physics of electrolysis are also disadvantageous because breaking the O-H bond requires so much energy all at once. Other multiple step processes don't need as much for each step, which offers more scope for catalysts.
But it is still good research.
"It has nearly three times the energy density of petrol ".
Is that comparing liquid H2 with Petrol? Or Molar H2 with Molar petrol/ethanol (petrol being a mixture of molecule types).
Making and storing liquid H2 is non trivial so that's a fairly significant point to brush over and a Mole of gasious H2 is going to need a lot more space than a mole of liquid petrol even at high pressure
" as does refining, making and silos tribute on carbon fuels... and batteries and everything else !!!"
False analogy: Carbon fuels aren't *energy storage*, but *energy source*. You don't use an iota of energy to *make* them first.
You dig it from the ground, basically for free and you've 30MJ/L energy on hand.
For H2 every joule it has, has to be taken from somewhere else first, multiplied by efficiency. H2 is a battery here but carbon fuels aren't even near.
In terms of energy per kg it doesn't really matter what form the hydrogen is in, but for energy per litre, which is important for transport(*), hydrogen is at best one third of the energy density (LOx).
Convenient table on Wikipedia.
(*) Unless you don't mind your car/lorry being 90% tankage.
Mole is a unit of 6.02214076×10^23 molecules of a substance
H2 is tiny, Petrol and Diesel are 7-8 chain hydrocarbons and huge, capacity wise in the size of 1 mol of P/D you could get containment, cooling and easily 4 mol of Hydrogen.
its a highly efficent transport mechanism.
there are working vehichles with H2, by honda, toyota and hyundai, the H2 containment and storage takes up less space than the Fuel tank, has a similar range, and can be filled in aboiut the same time.
"its a highly efficent transport mechanism."
Yes, *on paper*. You seem to forget that it *has* to be at least -170C and >100bars or so *just to stay liquid*.
And when it doesn't: *BOOM* says your container. Hydrogen *is really bad stuff to transport*. Really.
Liquid hydrogen is a genuine pipe dream for hydrogen fanatics, it's not feasible in any large scale transportable application .
"there are working vehichles with H2, by honda, toyota and hyundai, the H2 containment and storage takes up less space than the Fuel tank, has a similar range, and can be filled in aboiut the same time."
And cost the same? Of course not, but more than the rest of the car combined.
Also, none of those use liquid hydrogen, but just compressed gas. That means very high pressure and that means weight. Funny you forgot that.
I wonder what the energy density is, or my humongous extra loud farts.
It reminds me, when i was married, i did one of my loudest farts ever when in bed. My wife woke up and sat up asking "What was that, what was that ??? ".
After i had finally finished crying with laughter, i announced what i had just done. Needless to say, she was not happy.
There are three ways to store hydrogen: compressed, liquefied or bound to e.g. nickel. Each of these methods suck in its own special ways.
The problems with liquefying hydrogen are that it takes a lot of energy to get it this cold, keeping it cold and finding a safe place where it can reliably remain cold. Not ideal for most situations.
Binding hydrogen to usually some metal molecule has the advantage that this is very stable and thus quite safe. The major disadvantage is that since it's a stable connection, it's hard and thus very slow to get the hydrogen to become unbound again. The other major disadvantage is that this storage method is very bulky and heavy, making it only suitable for situations where you need stationary storage and aren't too worried about how fast you can get hydrogen back out.
Finally, the most common method of storage and what is generally used for transport applications is to compress the gas and storing it in super-thick walled (composite) tanks. This has to occur at very high pressures as hydrogen has a stupidly unreasonable power-to-volume ratio. These hydrogen tanks have a very limited lifespan and need to be regularly inspected for safety reasons.
In industrial applications, the preferred method is to produce needed hydrogen on the spot, in limited quantities for immediate use. See the issues with storage for why.
As far as general safety goes, hydrogen is a fairly unique gas in that it is highly inflammable, more than anything else. If mixed with an oxygen ratio between almost nothing and close to saturation, it'll happily and violently detonate. Over the past years there have been multiple explosions at hydrogen refueling stations and production facilities, including an accident last year in California that show just how much of a liability H2 is in general use: https://www.cnet.com/roadshow/news/hydrogen-fuel-cell-car-california-explosion/
As mentioned by others, the amazing thing about hydrocarbons is that they are very stable, very dense and easy to store. Hydrogen without the carbon is essentially the opposite. Hydrogen reacts with everything (which causes the metal embrittlement and violent reaction with oxygen), is the exact opposite of dense and is very hard to store (see above).
Current suggestions for hydrogen in the fuel mix is to add hydrogen to the natural gas pipelines, but as we'll one day want to stop using natural gas, we'll lose the one easy(-ish) way to transport hydrogen that way. Maybe a methane-based economy makes more sense than a hydrogen-based one? Can still use steam-reformation with the methane to get hydrogen where it's needed, but avoid the headaches of storing and transporting of hydrogen.
Isn't that what they do in those recombined fuel trials? Combine recovered carbon dioxide with hydrogen to make "regular" fuel?
Key to all of this is availability of cheap electricity (as you're basically looking at ways to store electric energy in a form you can transport easily) and I think this will really take off once we have green and nuclear* energy to a point where their price point matches fossil fuel.
I must admit I have always considered battery stored power a bit of a stopgap until we had something with a far higher energy density.
* I'm thinking the newer LIFTR Thorium reactors here, which also could be operated directly at the temperature required for the most efficient way to produce hydrogen (thermochemical, which needs some 950ºC to work).
John Bucknell (former SpaceX engineer) is proposing to use the 700 degree heat output by future molten salt nuclear reactors along with helium turbo inductor pumps (originally proposed for nuclear rockets) to produce 1000 degree heat and methanol cheaper per MWhr equivalent of today's petrol:
https://youtu.be/Q1Fi3BnwL94
molten salt nuclear reactors
Those are just a nuclear scientist way of going, "Here, hold my beer and watch this!"
You take all the of problems there already are with conventional reactors, then add a chemical plant for in-flow cleaning of 700 degree (nice, red hot) radioactive material, that, being a molten salt, is also corrosive to all know construction materials.
The very best coal fired power plants would go to 750 degrees superheated steam. They could not go higher because of material limitations and they would still have to strip down the oven and the superheater every few years to a decade in order to replace cracked pipework.
Never mind if the magical chemical separation plant works (mind, they couldn't get THORPE to work), Imagine stripping down and replacing pipework, valves and pumps conveniently filled up with deadly radioactive soldified goop - every few years!
The whole concept Just proves that 20% of any population one cares to select - are Morons!
Yes pumping radioactive salt around pipes is not a great idea, as they will always leak, and when they do you have an even more difficult cleanup problem than with a sodium cooled reactor.
However there are two proposed ways around this problem. Thorcon and Terrestrial Energy both propose to use a pool type reactor in a can that is replaced every seven years (this is possible with a molten salt cooled reactor vessel as they are unpressurized and are not housed in a steam explosion resistant steel and conrete containment dome.
Moltex Energy has possible an even simpler solution of putting the fuel salt (a Chloride salt) in vented steel pins*, controlling corrosion by having a lump of zirconium metal in the bottom (to make the salt strongly reducing), thenhaving these pins cooled by a flouride salt in a pool type reactor. This gets rid of the need for an online chemical processing plant as the fission products just remain in the fuel pins which are removed from the reactor every few years like standard uranium oxide ceramic fuel pins in today's pressurized water reactors.
*Today's standard uranium oxide fuel pins have to be removed somewhat prematurely due to the build up of Xenon gas (a fission product) in them that prevents the reactor from sustaining a chain reaction, another problem is that that gas in the tubes builds up to about 60 atmospheres (I think). The Dounreay fast sodium reactor experiment in Scotland tried to deal with these issues by having a uranium metal alloy sitting in vented fuel pins (the uranium sat in liquid sodium inside a steel fuel pin). You wouldn't want to try this in water cooled reactor as sodium and water react violently, but in a sodium cooled reactor it isn't a problem.However as radioactive fission products of Cesium, Iodine, and Strontium are produced, the metals (which are gases at reactor temperatures) vented out into the sodium coolant outside, making it highly radioactive. In Moltex's design the Iodine is still reduced to a non volatile Sodium Iodide salt that stays in the fuel pin, but the Cesium and Strontium are converted into Cesium Chloride and Strontium Chloride non volatile salts that also remain in the fuel pins (precipitating Zirconium metal ZrCl + Cs > CsCl + Zr).
https://www.youtube.com/watch?v=7qJpVClxzVM&t=1164s
One good thing about Generation 4 nuclear reactors like that, is that if they get high pressure or heat, then a safety plug blows/melts and the fluid or fuel, dumps into a containment bucket and cools down. No China syndrome here!
Typically the spent fuel may be highly radio active, BUT the half life is like 50 to 100 years. So in one human generation the spent fuel is safe. Plus the current spent fuel we have in storage at present old reactors, can be used with most Gen 4 designs. There goes the radioactive waste problem!
The salt processing cycle adds size again, but in general I have the impression that a LIFTR is overall substantially smaller as it doesn't need the expansion safety space of nuclear plants operating with water as coolant/heat transfer medium. After all, the original (abandoned) idea was to make a nuclear powered plane.
Where I see this becoming VERY interesting is in shipping and military applications. Shipping is the quiet polluter of the globe - cruise ships may have stopped being petri dishes for a while, but freight has increased. As for military, the obvious place is flight deck ships and subs (if you can stick a nuclear generator in a sub with existing tech, imagine how much more you can do with a reactor that is less risky and bulky), but it may also end up as a mobile energy plant for an army. The current supply chain (and heat signature) of theater deployment involves a massive amount of fuel transport, imagine you can strip a lot of that by either running your own power plant, or even produce on demand fuel in some way.
All of this is still far off or may not even happen, but the possibilities are interesting - and far better for the planet..
Are you sure you are using half-life correctly? A 100 year half-life means that it will be half as radioactive after 100 years as it was at the start. So to reduce the radioactivity to 0.125 of the original values will take 300 years, and if it was very radioactive at the start, it will probably still be radioactive after 300 years,
Also, you have to know what the decay products are, as they could also be radioactive with their own half-lives.
Actually, the coldness of liquid hydrogen is a potential energy resource, as a heat sink. You can run a heat engine, with ambient temperature as the heat source, and cold hydrogen as the heat sink. Due to the large temperature difference, I expect this could be quite efficient. This means that much of the energy put into liquefying the hydrogen could be recoverable.
For the energy revolution the hydrogen will need to be turned into methane. This makes the hydrogen easily storeable and transportable. Furthermore, Methanation uses CO2 to turn hydrogen into methane. Thus, you can plumb the exhaust stream of something you can not avoid, e.g. garbage incineration, into the loop and avoid emissions.
Yes it is, You're actually better off capturing the methane and burning it than letting the methane go into the atmosphere, the net impact of the CO2 from burning it is less than that of the Methane itself. And in the process you can generate electricity. It's not at all carbon neutral, but if you've got the methane you might as well use it rather than let it escape.
And it's not just the thawing tundra that is a potential source. We have lots of it under the oceans and those deposits are becoming unstable
https://en.wikipedia.org/wiki/Methane_clathrate#Methane_clathrates_and_climate_change
You don't need to split the hydrogen off: you can reduce water with something like CO (carbon monoxide) and go this route to produce hydrocarbons which are easy to store and transport. Currently, this costs more than drilling for oil and gas, but then so does the industrial production of hydrogen, which means it would be a target at least for arbitrage (à la E10 petrol which is made from corn, which is grown using fertiliser made from oil…) if not downright fraud.
"technologies that are relatively mature"
Algae, water, carbon dioxide and sunlight to produce carbohydrates.
Carbohydrates plus yeast to produce alcohol.
Alcohol or maybe some derivative such as biodiesel plus ICE produces water and carbon dioxide as by-products.
Fuel is distributed through the existing system.
Some very ancient technology and nothing that's immature.
not a problem but several
1 the explosive range is about 5% to 75% oh H2 in air, so it goes bang very easily and often when and where you don't want it. methane has a range of 8% to 18%
2 it is almost impossible to store, steel is right out of the question, but nickel is used in some short exposure environments, so instead of $600 for your material its $20k and then you have to replace it regularly. Use ammonia instead.
3 and H2 you spill is lost permanently, it goes to the top of the atmosphere and drifts off into the deep cosmos, but there is a lot of it on Earth.
4 H2 has been an industrial hazard for a long time (centuries), thus it is well characterised and electrolysis a text book example for 150 years. So this may make this step cheaper, making H2 is not the problem, it is storing it, not losing it and not blowing yourself or your customer up in using it.
5 H2 can be a liquid, but at boiling point of 20K, the economics look bad so use ammonia
written by an engineer with two degrees and 20+ years in the fuel and fuel storage industry
Thank you for these. Instead of ammonia (NH3), what about the Sabatier reaction and methane (CH4) or even methanol (CH3OH). I am sure burning ammonia produces nitrogen oxides. Methanol has the decency to be a liquid at room temp and pressure. Probably as hazardous to humans as drinking petrol (or sniffing petrol) which we aware not to do.
I believe that ethanol (and its little brother methnol) has problems can be corrosive when stored or processed in metal. I haven't seen details of the chemistry so I could be much mistaken. One of the problems that have bedevilled fuel cells such as those pioneered by Toyota. Hats off to them for doing this before it was fashionable and attracted such massive subsidies and investments.
This is actually IMO the key feature - by turning a dissolved chemical into a catalyst using microwaves, they have avoided all the usual difficulties of trying to maximise a (the) catalyst's surface area (e.g. the "a lot of two-dimensional cells that are stacked together" comment in the article).
If you have such a power source, why not just use it to drive the wheels instead?
It is challenging but not impossible to directly power automobiles with wind, solar, or nuclear sources. Generally, wind, solar, and nuclear are better arranged as stationary power plants that deliver electricity to trains and trolleys, to battery-powered vehicles, or to chemical reactors that produce hydrogen for cars.
Two separate things: power and storage. Spain could probably already meet most of its power demands using solar power during the day, but not at night and also it also requires a lot of land, because yields are relatively low. So chemical storage, which can be produced when there is excess capacity, and then used when their is excess demand is required; build it up on windy nights and warm sunny days, use it up when it's cold and dark. You want something with high energy density that is easily transportable.
"However, if we are to meet 2050 targets, we are probably well advised to use technologies that are relatively mature and can be manufactured at a larger scale right now," Jansen said.
But, given that present 'mature' technology is massively capital intensive, would you invest in any if you'd just read this article? That's a big problem in many areas. A technology is developed that works, but someone already has something in the lab that will be simpler, cleaner, 50% faster, and 90% cheaper. Granted it will take 2-3 years to fully develop, but it means anyone investing now have to recoup all their capital costs in that 2-3 years before they become redundant, instead of over 10-20 years that the plant could probably run for. Which seriously increases prices for users, who won't switch.
See "Cost of EVs and problems charging them" as an example
Excellent. We must break this cult of fossil fuels and realise that gasoline is just a battery store of energy, just like these other forms of electric batteries and hydrogen. Even when other forms of energy become much cheaper we still have the psychological lock in of cult status.
"gasoline is just a battery store of energy"
Blatant lie: It's a *source* of energy. *Anything* else is *empty store* and you need to fill it first. That costs money, a lot of money.
" Even when other forms of energy become much cheaper"
"When"?
Tell us, have you any idea what hydrocarbons (crude oil) actually cost? I can tell you, it's less than 1 dollar per barrel. The rest is profit. Even less for natural gas.
Other forms will never be even near that, until we run out of basically free hydrocarbons. That may take much longer you think.
Ok.
* Hydrogen is hard to extract from wherever it currently resides - water..
* It's hard to store because it leaks through the tiniest gaps
* It might explode
It's all very well debating which is the biggest problem. In reality it scarcely matters because they're all pretty serious. Years (decades?) have been expended on trying to overcome these issues to power cars or buses but progress has been minimal. A handful of cars here, or buses there, but no one is prepared to risk volume production. I don't blame them.
But why on earth is anyone still bothering to fund this.
Is it that various funding bodies keen for green publicity are being conned by scientists who should be a bit more responsible?
(And while I'm in rant mode, doesn't pretty much the same argument apply to money spent on carbon capture and storage?)
there are mainstream H2 powered cars, Buses and Trains.
The same three statements apply to P/D
P/D are becomming increasingly expensive to find and extract
Hydrogen delivery and creation Mechanisms are progressing fast and becoming cheaper
Hydrogen is re-usable, Carbon capture and storage is akin to alchemy at this stage, and can't provide a solution now to the problem of climate change, that H2 is neatly placed to do.
"Hydrogen delivery and creation Mechanisms are progressing fast and becoming cheaper"
No they aren't, as there are .. eh ... material problems. H2 doesn't stay inside *anything*. Oh, it's easy to create with solar energy and if you use it on the spot, transport isn't a major issue.
Otherwise delivery isn't economically feasible in any scale. This has been tried since 1970s and progress is basically zero.
And that's an atom level issue, there's no way to solve it, even less fast or cheap.
Anyone claiming so has no idea what they are talking about.
"Hydrogen is re-usable"
Yea, same way as battery is, but the energy efficiency to do so is *horrible*. Even worse than petrol fueled car engine.
It makes sense only if the energy used to create H2 is free. In very large scale.
Even simple hydrocarbon (octane, for example) is 100* easier to store and transport
The military will fund alternates. Presently among the largest component of navies and aerial forces costs is the fuel bill and anything that can cut that cost is put in the good column. In the mid 60s Analog had a featured article (The Hydrogen Economy) about the soon on the scene fuel, Hydrogen, with it a picture of a Model T that had been modified to run on Hydrogen and have we left that place in the parking lot [car park]. Like fusion the research for making it practical will go on forever because the investment and employment is in the search sector .
Given the sunk costs of very-expensive equipment, I think they'll be turning their attention more towards synthetic hydrocarbons. The US Navy, for example, is researching ways to do this on their aircraft carriers (which have nuclear reactors onboard, plenty of seawater to exploit, lots of gas-guzzling jets to feed, and a limit to their carrying capacity which limits their tours of duty).
...nearly three times the energy density of petrol...
The slight snag is that a kilo of hydrogen occupies eleven cubic metres while three kilos of petrol doesn't get to a quarter on the fuel gauge.
So it has to be compressed, a lot.
Now, the other significant snag with hydrogen is it's the very devil itself to get to stay inside a fuel system so the firey bit of the process stays where it belongs. Putting it under massive levels of pressure only serves to make the inevitable kaboom larger.
" It has nearly three times the energy density of petrol (gasoline) or diesel "
That's BS. H2 0,08988 g/L, 286 kJ/mol, yes, but only 3MJ/L compared to 30 MJ/L of diesel.
As fuel is stored in a tank, i.e. a volume, weight is basically irrelevant and 10% of diesel means 10 times as large tank. Good luck on that.
Nasty fact any hydrogen fan tries to lose by referring to weight. Only you can't store or move weight, it's always volume.
Also H2 *leaks*.
2% per week is pretty normal in a large container regardless of the material (typically steel). It seeps between iron atoms in the grid and there's nothing you can do to stop that.
All this talk about electrolysis, and no one is mentioning all the pure O2 produced.
If that were fed (separately) to where the H2 is to be burnt, wouldn't it burn much better than with air?
Also releasing less nitrogen pollutants.
It could also make burning other stuff (e.g. rubbish incineration) much more efficient.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
