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As it stands, I don't see how hydrogen proponents in either vehicles or energy distribution can recoup the head start of pure electric. The best electrolysis +

by yholio 6y ago

As it stands, I don't see how hydrogen proponents in either vehicles or energy distribution can recoup the head start of pure electric. The best electrolysis + fuel cell cycles commercially available are maybe 35-40% efficient (electric-electric). Maybe someday, 20 years from now, some quantum catalyst gizmo will push that to 90%. For vehicles you then need another step of compression to force the hydrogen inside a very high pressure tank - by the laws of thermodynamics this can only cost you energy regardless of any technological advancement. Meanwhile, electric batteries today are over 90% eficient on the whole charge-delivery cycle, the industry is rapidly gaining momentum, charge networks are built, the cost of components only goes down. Compared to hydrogen, battery electrics are today where internal combustion cars were compared with electrics 100 years ago: the market has spoken and the massive economies of scale of the winner will relegate the competitor to very specialized niches. And once you lose the hydrogen vehicles, the whole distribution network becomes a very dubious business proposition. Why build H2 pipes that need expensive and inefficient electric conversion endpoints, when you can rely on and extend the existing electric distribution networks? Indeed, you can store hydrogen, but what advantage do you have by storing it closer to the consumption point, instead of a grid connected hydrogen battery that generates, stores and consumes hydrogen as requested by the smart grid? In that scenario, hydrogen becomes just one of multiple competing energy storage technologies, together with pumped storage, grid connected batteries etc., all together helping to regulate intermittent renewables.

eggy 6y ago
I would like to see a cost comparison from true start to finish. What is the manufacturing/resource cost of making batteries? What is the efficiency or cost of producing the electricity to charge the batteries? How does this compare to making the photocatalyst and compressing and/or distributing the hydrogen compare? I remember seeing a breakdown of making batteries, distributing them, and charging them, compared with oil resource procurement, refining, and distribution. I'll take a look again, but does anyone have such a table reference? Thanks!
gpapilion 6y ago
Electric still has some major disadvantages particularly around refuel times. That’s the one major area I see, and the distribution story is better for electric but also still evolving. For example the 6 chargers at the mall aren’t really enough, and scaling to a few hundred isn’t easy or viable.
- newacct583 6y ago
  > scaling to a few hundred isn’t easy or viable That seems wrong to me. I mean, objectively I'd expect the construction expense of a gasoline fueling station to be much higher than just running more electrical distribution lines to a major shopping area. I think you're making the mistake of comparing the "cost" of new construction to the sunk cost of existing infrastructure. Those gas stations don't last forever and the cost to disassemble and rebuild them needs to be part of your analysis.
- smegger001 6y ago
  It scales faster than building out a whole new infrastructure especially since it gets to piggyback off of existing electrical distribution networks, and any one with a driveway/garage can charge there own vehicle by plugging it into the wall albeit slower than at a purpose built charger. many of those will have a personal charger though so even that will be faster. also batteries are less prone to explosive decompression in a accident than storage tanks of highly compressed explosive gas.
exabrial 6y ago
Real Engineering did a video about this and committed the same fallacy. Engineers nearly always overlook practicality and chase perfection. Heres the thing: It's not about efficiency, it's about convenience. Transferring 2700 megajoules of energy to an f150 via gasoline in a few minutes is very convenient, something that would take a Tesla a few hours. If consumers were concerned with efficiency the same way engineers were, we'd all be driving electric hummers and cybertrucks. Hydrogen isn't aiming to be as efficient as batteries. It's assuming to be as convenient as gasoline, but with little environmental impact.
- ttul 6y ago
  Also, it’s not just an option for passenger vehicles. Natural gas can be replaced with hydrogen in the existing pipeline network, providing distribution of heating gas at extremely low cost and with a very minimal investment in retooling of existing furnaces.
  - exabrial 6y ago
    Hydrogen pipelines with probably never be a thing. It's safer and more convenient to just produce h2 at the distribution point. The oil refinery/pipeline model exists because of the difficulty in synthesizing hydrocarbons, whereas h2 is (relatively speaking) far easier to create.
    - _jahh 6y ago
      I believe OP is thinking more municipal pipes that feed individual buildings rather than a distribution pipeline like Keystone XL.
  - yholio 6y ago
    Aside from blending small amounts on hydrogen in existing methane feeds, no one will do this. Pure hydrogen is a dangerous gas that burns much hotter than methane, can seep trough the tiniest of cracks that methane/propane cannot and can even penetrate the crystal lattice of common metals such as steel, leading to embrittlement and catastrophic failure under normal use. By the time you upgrade the methane infrastructure to handle it, you will build a whole network all together. And there is also an economic argument: methane/propane work because they are pure energy coming from the ground, you can only burn them to recover it. To produce Hidrogen, you need electric energy, or some very hot source that could be turn to electricity at a high efficiency. It makes zero sense to generate hidrogen in order to burn it for domestic heating, when the equivalent electric energy could give 3-5 more heat using electric heat pumps.
rarefied_tomato 6y ago
Simple counterargument: you can't make a large electric plane. The energy density of a battery is too low.
- yholio 6y ago
  Nor can you make a hydrogen plane with current (compressed hidrogen) technology, its tanks would be much too bulky and heavy. Unless you are proposing to transform planes into some sort of foam-covered Space Shuttle external tanks storing liquid hidrogen, our best bet for carbon neutral flight is some sort of fuel synth or biofuel.
lowercase1 6y ago
1. Hydrogen distribution might be able to use/share natural gas infrastructure (not high yield so embridlement isn't as big an issue) 2. Hydrogen is used for chemical processes (refining/ammonia) that can serve as a first step even if use for energy storage never becomes feasible. 3.Hydrogen is cheaper to store (<$10) per kWh than basically anything else (>$50). But it basically won't be relevant until we have 12 hours of storage and zero marginal cost electricity 50+% of the year. Then it may be cheaper than overbuilding renewables or capturing gas emissions to cover the last 10-20 percent
- neaanopri 6y ago
  If there's abundant pure hydrogen, synthesizing methane gets a lot easier, and we can use natural gas infra with no modifications. One of the cases I think about for Hydrogen is moving energy around globally. The Sahara has tons of energy potential, but nobody lives there. How can we move that energy around efficiently, even across continents? Definitely not "batteries on boats"
  - deleted 6y ago
    [deleted]
  - sunstone 6y ago
    A project has been announced to move energy from the Australian outback to Singapore, a distance of over 3000km mostly underwater.
laumars 6y ago
I’m not going to pretend to be as well researched on this point as yourself but one thing you hadn’t mentioned is the environmental impact of disposing batteries. Isn’t that the biggest complaint against electric cars (in much the same way that fission reactors are criticised for the radioactive matter that needs to be disposed of — albeit the timescales involved are different by orders of magnitude).
- _jahh 6y ago
  if anything it's the environmental and social impact of the mining of the minerals vs the disposal.
- DarmokJalad1701 6y ago
  > the environmental impact of disposing batteries Why would anyone want to discard these batteries with precious minerals? 1. Their lifetime is measured in decades (first in EVs and then in grid-storage) as compared to single-use for gas. 2. They (at least the various types of Li-Ion cells) are 100% recyclable. Battery production will probably switch to "urban mining" once enough has been manufactured to supply the global fleet. Tesla recently mentioned during their battery day presentation that they plan to do exactly this. Re-manufacturing batteries will be far cheaper than mining fresh raw materials once enough EoL batteries are available.
  - laumars 6y ago
    That’s interesting. I wasn’t aware that was now possible with battery tech. Thanks for the explanation.
    - bananabreakfast 6y ago
      check out https://www.redwoodmaterials.com/ https://www.redwoodmaterials.com/ All EV batteries are 100% recyclable and this company was founded by the original CTO of Tesla to do just that.
Aerroon 6y ago
The problem with electric is the specific energy of batteries (how much energy per weight). Current batteries used in cars top out at around 300 Wh/kg. That's 1.08 MJ/kg. Gasoline has a specific energy of 46.4 MJ/kg. Hydrogen has even higher specific energy, but with hydrogen you need a lot of weight for safety reasons. Hydrogen probably isn't going to give you much note than gasoline in specific energy. That's still 40 times better than batteries though. As an aside, body fat has a specific energy of 38 MJ/kg.
- yholio 6y ago
  For hydrogen, the mass of the gas itself is negligible compared to the weight of the tank used to store it in compressed form: Therefore, an advanced composite container holding 5.7 kg of CH, would provide a range of 300 miles in a hydrogen vehicle, but will require a storage space of 260 liters (69 gallons) and weigh about 230 lb (104 kg). This will then be about nine times bulkier and three times heavier than a typical 7.5-gallon gasoline tank. (https://www.fsec.ucf.edu/en/consumer/hydrogen/basics/documents/task2_gaseous_h2.pdf ) So what you get overall is on par with the best batteries that are becoming available - which however have much better volumetric energy density. This is especially important at higher speeds: the energy required to accelerate a large mass can by recovered with a high efficiency using regenerative braking, while the friction of a bulky vehicle with air is lost (alternatively, passengers will drive a larger vehicle than required since the internal space is insuficient).
- theshrike79 6y ago
  Electric engines convert those Megajoules to actual motion much more efficiently than combustion engines.
- bananabreakfast 6y ago
  This is a disingenuous comparison. The specific energy of gasoline does not matter unless put into context with the efficiency of the mechanism extracting it into useful work. The mechanism in this case is an internal combustion engine and its efficiency is around 10%. The mechanism for extracting useful work from a battery is an electric motor, and it achieves ~98% efficiency. Which means gas is only ~4X more dense in terms of actual useful energy. So a battery pack weighing 4x more than full gas tank to get the same range is not unreasonable at all and is basically what a Tesla is.
zbrozek 6y ago
I think we're going to see a diversification in energy storage and power delivery systems for different applications. There's lots of uses for hydrogen beyond running your passenger car. It's a feedstock into a lot of chemistry (hydrogenating food, making fertilizer, reducing ores) as well as various high temperature processes. It looks like you can blend it at some modest proportion into existing natural gas infrastructure to lighten its environmental burden somewhat. Closer to my personal sphere, I'd be interested in using it for longer-term energy storage. It'd be amazing to be able to have some onsite high pressure or even cryogenic storage of hydrogen to be able to store a summer solar surplus for use in the winter. And yes, that's in addition to batteries to handle short term (hours up to maybe a week) of generation/load mismatches. I'd probably want to turn some back into electricity, but I'd be happy to simply burn a bunch too.
- smegger001 6y ago
  >Closer to my personal sphere, I'd be interested in using it for longer-term energy storage. It'd be amazing to be able to have some onsite high pressure or even cryogenic storage of hydrogen to be able to store a summer solar surplus for use in the winter. Hydrogen really doesn't like to be stored though. It also ruins any storage vessel it is kept in long term. You see Hydrogen is the smallest atom, small enough to fit between atoms of other materiel. and it will work its way through materials and sometimes bonding with the material sometimes just escaping, this creates a spoilage of the materiel the holding vessel is made of resulting in hydrogen embrittlement, creation of cracks and voids inside the metal, About the only materiel we believe to be immune are carbon fullerenes and graphene. Which we have had problems producing at scale. as for cryonic storing it you are just adding another energy cost to they system because you are spending more energy still to chill the hydrogen >It looks like you can blend it at some modest proportion into existing natural gas infrastructure to lighten its environmental burden somewhat. and this makes less since. You have to spend more energy to make the H_2 by splitting the H2O than you get out of burning the H_2, so adding it to natural gas to make it more environmentally efficient doesn't make since as you are increasing the net energy cost of the system than just burning the natural gas.
  - 6y ago
samstave 6y ago
Less pollution in the future and less need for lithium? So maybe that’s a better trade off for the planet.
adamcstephens 6y ago
How should we obtain enough electric generation to offset the lost of hydrocarbons?
ed25519FUUU 6y ago
Hydrogen has an energy density of 120 MJ/kg. Gasoline has an energy density of 46.4 MJ/kg. Lithium ion batteries at 2.5. They’re not even in the same ballpark.
- newacct583 6y ago
  Only aircraft care, though. Fuel weight in other applications is basically a non-issue except for really niche gadgets.
- yholio 6y ago
  > Hydrogen has an energy density of 120 MJ/kg. Divide that by 15 to get real world densities of compressed hydrogen composite storage tanks, you need a 104 Kg tank to store 7.5 Kg of hydrogen, for a total of 111.5 kg when full.
TheRealPomax 6y ago
So, you don't see how EV could take over from gasoline? Because you're describing the exact same "the infra's not there, and the tech's not good enough" situation as before. If hydrogen extraction can be be made efficient enough to economically make more sense than batteries, that's the only necessary criterium. If it can, the rest is a matter of time. If even with this approach it can't, then it won't happen. It's really just economics.
konschubert 6y ago
The efficiency argument is brought up a lot, but it ignores that Energy is cheap, Storage is expensive. If storing a KWh of power costs 50 Cent in a battery and 5 Cent in a fuel cell, then it doesn’t matter if you pay 10 or 20 Cent per KWh of fuel. Of course this is an example with made up numbers, but the point is valid.
ed_balls 6y ago
Electric cars are at the sweet spot. If you look at larger vehicles e.g. Semi-trailer truck, battery doesn't make sense. To have a good range you would need 5 tons of batteries which limits your cargo and it's not economic. Then you have electric ships and planes.
bumby 6y ago
Yours is a very good post, I’m just curious of you could elaborate on >electric batteries today are over 90% eficient on the whole charge-delivery cycle Isn’t the most common electrical delivery via natural gas power plants which are generally 40%-50% efficient? Meaning the 90% is a downstream measure from the source and not really “whole cycle”? It would be interesting to see comparisons of the true life-cycle efficiency of different modes of energy delivery and storage.
benlivengood 6y ago
Hydrogen may be cheaper as energy storage for meeting peak load on a mostly-renewable electrical grid. In the short term (20 years) the loss of thermodynamic efficiency isn't much compared to the ability to re-use existing steam turbines from natural gas plants. Water and carbon fiber is much more widely available than the precursors to batteries and so the working medium is more accessible world-wide. If there's a place for hydrogen in the electrical grid then there will be cheap hydrogen available for other potential uses and the market will likely find some niches. Long-haul transport is a big one; instead of electrifying all freight rails in a country use locomotives with hydrogen fuel cells.
atlgator 6y ago
As long as we have coal plants powering our electrical grid we should seek alternatives that would replace or reduce reliance on them.
- bananabreakfast 6y ago
  This is entirely false. It's called the long tailpipe theory. Every study that suggests this conclusion was published by Oil companies in the 90s to shut down California's effort to switch to electric cars by the year 2000. No actual study has ever found this conclusion and in fact all find the opposite. Even with the worse polluting power generating plants, charging an EV directly off of the massive grid power generation is far more efficient in terms of pollution than burning gas inside your car.
deleted 6y ago
[deleted]
phkahler 6y ago
I don't think hydrogen powered vehicles are viable. But what if solar-splitting of water followed by electricity generation with a fuel cell turned out the be more efficient than the best solar cells? I doubt it, but it seems like a maybe.
dmead 6y ago
most of the universe is hydrogen. it's easier for a base on some other planet to find hydrogen than set up a battery factory.
- mr_toad 6y ago
  Hydrogen is abundant in gas clouds, in Stars, and gas giants. But unbound molecular hydrogen (H2) is basically nonexistent on terrestrial planets since their gravity is insufficient to hold onto it.
ZeroGravitas 6y ago
I think you're correct as far as you go, but hydrogen has other uses, as an input to chemicals such as Ammonia that are currently produced and/or used in ways that release CO2. Just Ammonia for fertilizer alone generates 2% of annual CO2 emmisions, so that alone is a market worth targetting in both environmental and business sense. As soon as the inevitable policy response kicks in there will be a massive market for green ammonia (and therefore hydrogen). Ammonia has a decent shot at being a shipping or aviation fuel too, but many of its alternatives need the same input of green hydrogen anyway so can share costs and scale with Ammonia production. As for intermittent renewables, we're approaching the point where we shift from mostly underproduced and only occasionally overprovisioned to them being near permanently overprovisioned and needing to find uses for that electricity that can be rarely halted to help the grid a few times a year. Hydrogen production fits the cost profile for long-term/seasonal storage that no lithium battery can hit, even if they drop in price even more than currebtly predicted.
ashtonkem 6y ago
There are some applications where energy density is far more important than energy efficiency. Airplanes come to mind. You would accept the pumping losses when it comes to filling a 737 with hydrogen, because you literally can’t make that plane work with batteries at this point in time.
- kjaftaedi 6y ago
  Glad to find this in the responses. Air transport is quite possibly the best use case for hydrogen fuel that I can think of, and likely the only way we'll get sustainable air travel in the near future.
  - rootusrootus 6y ago
    Wouldn't it be easier to just work on efficient synthesis of jet fuel? Then we could just keep the rest of the infrastructure the same. Sometimes I wonder if that would end up being a solution for cars, too. It would certainly solve a few difficult edge cases that electrification will have a hard time overcoming.
    - mr_toad 6y ago
      > Wouldn't it be easier to just work on efficient synthesis of jet fuel? Some synthetic fuel production processes require hydrogen, so a cheap hydrogen source would still be useful.
- rootusrootus 6y ago
  > when it comes to filling a 737 That brings up an interesting point. I wonder how much of a factor fuel is in dictating the preferred size for an airliner. Maybe if the fuel economics and physics change, we'll see an evolution towards larger numbers of smaller point-to-point airliners.
dghughes 6y ago
Transportation aside hydrogen storage is great for its energy density. Storing it locally probably as a hydride. I'm picturing home use replacing oil or gas with hydrogen combined with a fuel cell. It would be great for high demand situations where solar plus a battery setup capacity was too low. For example winter little sun (low on the horizon too) and a long cold spell.
_fizz_buzz_ 6y ago
1.) There is already a 240 km hydrogen pipeline network in Germany (and probably in other countries as well) [1]. It connects chemical plants in the rhein-ruhr region. So there is already a huge market for hydrogen. These chemical plants will need hydrogen in the future. If we want to get away from using oil and gas and become CO2 neutral, we need a solution for those industries. 2.) I don't see air travel happening with batteries (except really short distances or really small planes). Weight is just too much of a factor in air travel and the energy density is just too far off with batteries. Hydrogen would maybe be a solution or some fuel that is synthesised from hydrogen. [1] https://industrie.airliquide.de/wasserstoffanlagen https://industrie.airliquide.de/wasserstoffanlagen
Hypx 6y ago
It should be pointed out that stationary systems can easily exceed 40% if we really wanted to. By combining heat and power generation you could push net efficiency out to 60% or higher. You also don't need to worry about compression or mobile storage saving you some more efficiency there too.
qPM9l3XJrF 6y ago
How about e.g. aeronautical applications where energy density is valuable?

by yholio 6y ago

eggy 6y ago

I would like to see a cost comparison from true start to finish. What is the manufacturing/resource cost of making batteries? What is the efficiency or cost of producing the electricity to charge the batteries? How does this compare to making the photocatalyst and compressing and/or distributing the hydrogen compare? I remember seeing a breakdown of making batteries, distributing them, and charging them, compared with oil resource procurement, refining, and distribution. I'll take a look again, but does anyone have such a table reference? Thanks!

gpapilion 6y ago

Electric still has some major disadvantages particularly around refuel times. That’s the one major area I see, and the distribution story is better for electric but also still evolving. For example the 6 chargers at the mall aren’t really enough, and scaling to a few hundred isn’t easy or viable.

newacct583 6y ago
> scaling to a few hundred isn’t easy or viable That seems wrong to me. I mean, objectively I'd expect the construction expense of a gasoline fueling station to be much higher than just running more electrical distribution lines to a major shopping area. I think you're making the mistake of comparing the "cost" of new construction to the sunk cost of existing infrastructure. Those gas stations don't last forever and the cost to disassemble and rebuild them needs to be part of your analysis.
smegger001 6y ago
It scales faster than building out a whole new infrastructure especially since it gets to piggyback off of existing electrical distribution networks, and any one with a driveway/garage can charge there own vehicle by plugging it into the wall albeit slower than at a purpose built charger. many of those will have a personal charger though so even that will be faster. also batteries are less prone to explosive decompression in a accident than storage tanks of highly compressed explosive gas.

exabrial 6y ago

Real Engineering did a video about this and committed the same fallacy. Engineers nearly always overlook practicality and chase perfection. Heres the thing: It's not about efficiency, it's about convenience. Transferring 2700 megajoules of energy to an f150 via gasoline in a few minutes is very convenient, something that would take a Tesla a few hours. If consumers were concerned with efficiency the same way engineers were, we'd all be driving electric hummers and cybertrucks. Hydrogen isn't aiming to be as efficient as batteries. It's assuming to be as convenient as gasoline, but with little environmental impact.

ttul 6y ago
Also, it’s not just an option for passenger vehicles. Natural gas can be replaced with hydrogen in the existing pipeline network, providing distribution of heating gas at extremely low cost and with a very minimal investment in retooling of existing furnaces.
- exabrial 6y ago
  Hydrogen pipelines with probably never be a thing. It's safer and more convenient to just produce h2 at the distribution point. The oil refinery/pipeline model exists because of the difficulty in synthesizing hydrocarbons, whereas h2 is (relatively speaking) far easier to create.
  - _jahh 6y ago
    I believe OP is thinking more municipal pipes that feed individual buildings rather than a distribution pipeline like Keystone XL.
- yholio 6y ago
  Aside from blending small amounts on hydrogen in existing methane feeds, no one will do this. Pure hydrogen is a dangerous gas that burns much hotter than methane, can seep trough the tiniest of cracks that methane/propane cannot and can even penetrate the crystal lattice of common metals such as steel, leading to embrittlement and catastrophic failure under normal use. By the time you upgrade the methane infrastructure to handle it, you will build a whole network all together. And there is also an economic argument: methane/propane work because they are pure energy coming from the ground, you can only burn them to recover it. To produce Hidrogen, you need electric energy, or some very hot source that could be turn to electricity at a high efficiency. It makes zero sense to generate hidrogen in order to burn it for domestic heating, when the equivalent electric energy could give 3-5 more heat using electric heat pumps.

rarefied_tomato 6y ago

Simple counterargument: you can't make a large electric plane. The energy density of a battery is too low.

yholio 6y ago
Nor can you make a hydrogen plane with current (compressed hidrogen) technology, its tanks would be much too bulky and heavy. Unless you are proposing to transform planes into some sort of foam-covered Space Shuttle external tanks storing liquid hidrogen, our best bet for carbon neutral flight is some sort of fuel synth or biofuel.

lowercase1 6y ago

1. Hydrogen distribution might be able to use/share natural gas infrastructure (not high yield so embridlement isn't as big an issue) 2. Hydrogen is used for chemical processes (refining/ammonia) that can serve as a first step even if use for energy storage never becomes feasible. 3.Hydrogen is cheaper to store (<$10) per kWh than basically anything else (>$50). But it basically won't be relevant until we have 12 hours of storage and zero marginal cost electricity 50+% of the year. Then it may be cheaper than overbuilding renewables or capturing gas emissions to cover the last 10-20 percent

neaanopri 6y ago
If there's abundant pure hydrogen, synthesizing methane gets a lot easier, and we can use natural gas infra with no modifications. One of the cases I think about for Hydrogen is moving energy around globally. The Sahara has tons of energy potential, but nobody lives there. How can we move that energy around efficiently, even across continents? Definitely not "batteries on boats"
- deleted 6y ago
  [deleted]
- sunstone 6y ago
  A project has been announced to move energy from the Australian outback to Singapore, a distance of over 3000km mostly underwater.

laumars 6y ago

I’m not going to pretend to be as well researched on this point as yourself but one thing you hadn’t mentioned is the environmental impact of disposing batteries. Isn’t that the biggest complaint against electric cars (in much the same way that fission reactors are criticised for the radioactive matter that needs to be disposed of — albeit the timescales involved are different by orders of magnitude).

_jahh 6y ago
if anything it's the environmental and social impact of the mining of the minerals vs the disposal.
DarmokJalad1701 6y ago
> the environmental impact of disposing batteries Why would anyone want to discard these batteries with precious minerals? 1. Their lifetime is measured in decades (first in EVs and then in grid-storage) as compared to single-use for gas. 2. They (at least the various types of Li-Ion cells) are 100% recyclable. Battery production will probably switch to "urban mining" once enough has been manufactured to supply the global fleet. Tesla recently mentioned during their battery day presentation that they plan to do exactly this. Re-manufacturing batteries will be far cheaper than mining fresh raw materials once enough EoL batteries are available.
- laumars 6y ago
  That’s interesting. I wasn’t aware that was now possible with battery tech. Thanks for the explanation.
  - bananabreakfast 6y ago
    check out https://www.redwoodmaterials.com/ https://www.redwoodmaterials.com/ All EV batteries are 100% recyclable and this company was founded by the original CTO of Tesla to do just that.

Aerroon 6y ago

The problem with electric is the specific energy of batteries (how much energy per weight). Current batteries used in cars top out at around 300 Wh/kg. That's 1.08 MJ/kg. Gasoline has a specific energy of 46.4 MJ/kg. Hydrogen has even higher specific energy, but with hydrogen you need a lot of weight for safety reasons. Hydrogen probably isn't going to give you much note than gasoline in specific energy. That's still 40 times better than batteries though. As an aside, body fat has a specific energy of 38 MJ/kg.

yholio 6y ago
For hydrogen, the mass of the gas itself is negligible compared to the weight of the tank used to store it in compressed form: Therefore, an advanced composite container holding 5.7 kg of CH, would provide a range of 300 miles in a hydrogen vehicle, but will require a storage space of 260 liters (69 gallons) and weigh about 230 lb (104 kg). This will then be about nine times bulkier and three times heavier than a typical 7.5-gallon gasoline tank. (https://www.fsec.ucf.edu/en/consumer/hydrogen/basics/documents/task2_gaseous_h2.pdf ) So what you get overall is on par with the best batteries that are becoming available - which however have much better volumetric energy density. This is especially important at higher speeds: the energy required to accelerate a large mass can by recovered with a high efficiency using regenerative braking, while the friction of a bulky vehicle with air is lost (alternatively, passengers will drive a larger vehicle than required since the internal space is insuficient).
theshrike79 6y ago
Electric engines convert those Megajoules to actual motion much more efficiently than combustion engines.
bananabreakfast 6y ago
This is a disingenuous comparison. The specific energy of gasoline does not matter unless put into context with the efficiency of the mechanism extracting it into useful work. The mechanism in this case is an internal combustion engine and its efficiency is around 10%. The mechanism for extracting useful work from a battery is an electric motor, and it achieves ~98% efficiency. Which means gas is only ~4X more dense in terms of actual useful energy. So a battery pack weighing 4x more than full gas tank to get the same range is not unreasonable at all and is basically what a Tesla is.

zbrozek 6y ago

I think we're going to see a diversification in energy storage and power delivery systems for different applications. There's lots of uses for hydrogen beyond running your passenger car. It's a feedstock into a lot of chemistry (hydrogenating food, making fertilizer, reducing ores) as well as various high temperature processes. It looks like you can blend it at some modest proportion into existing natural gas infrastructure to lighten its environmental burden somewhat. Closer to my personal sphere, I'd be interested in using it for longer-term energy storage. It'd be amazing to be able to have some onsite high pressure or even cryogenic storage of hydrogen to be able to store a summer solar surplus for use in the winter. And yes, that's in addition to batteries to handle short term (hours up to maybe a week) of generation/load mismatches. I'd probably want to turn some back into electricity, but I'd be happy to simply burn a bunch too.

smegger001 6y ago
>Closer to my personal sphere, I'd be interested in using it for longer-term energy storage. It'd be amazing to be able to have some onsite high pressure or even cryogenic storage of hydrogen to be able to store a summer solar surplus for use in the winter. Hydrogen really doesn't like to be stored though. It also ruins any storage vessel it is kept in long term. You see Hydrogen is the smallest atom, small enough to fit between atoms of other materiel. and it will work its way through materials and sometimes bonding with the material sometimes just escaping, this creates a spoilage of the materiel the holding vessel is made of resulting in hydrogen embrittlement, creation of cracks and voids inside the metal, About the only materiel we believe to be immune are carbon fullerenes and graphene. Which we have had problems producing at scale. as for cryonic storing it you are just adding another energy cost to they system because you are spending more energy still to chill the hydrogen >It looks like you can blend it at some modest proportion into existing natural gas infrastructure to lighten its environmental burden somewhat. and this makes less since. You have to spend more energy to make the H_2 by splitting the H2O than you get out of burning the H_2, so adding it to natural gas to make it more environmentally efficient doesn't make since as you are increasing the net energy cost of the system than just burning the natural gas.
- 6y ago

samstave 6y ago

Less pollution in the future and less need for lithium? So maybe that’s a better trade off for the planet.

adamcstephens 6y ago

How should we obtain enough electric generation to offset the lost of hydrocarbons?

ed25519FUUU 6y ago

Hydrogen has an energy density of 120 MJ/kg. Gasoline has an energy density of 46.4 MJ/kg. Lithium ion batteries at 2.5. They’re not even in the same ballpark.

newacct583 6y ago
Only aircraft care, though. Fuel weight in other applications is basically a non-issue except for really niche gadgets.
yholio 6y ago
> Hydrogen has an energy density of 120 MJ/kg. Divide that by 15 to get real world densities of compressed hydrogen composite storage tanks, you need a 104 Kg tank to store 7.5 Kg of hydrogen, for a total of 111.5 kg when full.

TheRealPomax 6y ago

So, you don't see how EV could take over from gasoline? Because you're describing the exact same "the infra's not there, and the tech's not good enough" situation as before. If hydrogen extraction can be be made efficient enough to economically make more sense than batteries, that's the only necessary criterium. If it can, the rest is a matter of time. If even with this approach it can't, then it won't happen. It's really just economics.

konschubert 6y ago

The efficiency argument is brought up a lot, but it ignores that Energy is cheap, Storage is expensive. If storing a KWh of power costs 50 Cent in a battery and 5 Cent in a fuel cell, then it doesn’t matter if you pay 10 or 20 Cent per KWh of fuel. Of course this is an example with made up numbers, but the point is valid.

ed_balls 6y ago

Electric cars are at the sweet spot. If you look at larger vehicles e.g. Semi-trailer truck, battery doesn't make sense. To have a good range you would need 5 tons of batteries which limits your cargo and it's not economic. Then you have electric ships and planes.

bumby 6y ago

Yours is a very good post, I’m just curious of you could elaborate on >electric batteries today are over 90% eficient on the whole charge-delivery cycle Isn’t the most common electrical delivery via natural gas power plants which are generally 40%-50% efficient? Meaning the 90% is a downstream measure from the source and not really “whole cycle”? It would be interesting to see comparisons of the true life-cycle efficiency of different modes of energy delivery and storage.

benlivengood 6y ago

Hydrogen may be cheaper as energy storage for meeting peak load on a mostly-renewable electrical grid. In the short term (20 years) the loss of thermodynamic efficiency isn't much compared to the ability to re-use existing steam turbines from natural gas plants. Water and carbon fiber is much more widely available than the precursors to batteries and so the working medium is more accessible world-wide. If there's a place for hydrogen in the electrical grid then there will be cheap hydrogen available for other potential uses and the market will likely find some niches. Long-haul transport is a big one; instead of electrifying all freight rails in a country use locomotives with hydrogen fuel cells.

atlgator 6y ago

As long as we have coal plants powering our electrical grid we should seek alternatives that would replace or reduce reliance on them.

bananabreakfast 6y ago
This is entirely false. It's called the long tailpipe theory. Every study that suggests this conclusion was published by Oil companies in the 90s to shut down California's effort to switch to electric cars by the year 2000. No actual study has ever found this conclusion and in fact all find the opposite. Even with the worse polluting power generating plants, charging an EV directly off of the massive grid power generation is far more efficient in terms of pollution than burning gas inside your car.

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phkahler 6y ago

I don't think hydrogen powered vehicles are viable. But what if solar-splitting of water followed by electricity generation with a fuel cell turned out the be more efficient than the best solar cells? I doubt it, but it seems like a maybe.

dmead 6y ago

most of the universe is hydrogen. it's easier for a base on some other planet to find hydrogen than set up a battery factory.

mr_toad 6y ago
Hydrogen is abundant in gas clouds, in Stars, and gas giants. But unbound molecular hydrogen (H2) is basically nonexistent on terrestrial planets since their gravity is insufficient to hold onto it.

ZeroGravitas 6y ago

I think you're correct as far as you go, but hydrogen has other uses, as an input to chemicals such as Ammonia that are currently produced and/or used in ways that release CO2. Just Ammonia for fertilizer alone generates 2% of annual CO2 emmisions, so that alone is a market worth targetting in both environmental and business sense. As soon as the inevitable policy response kicks in there will be a massive market for green ammonia (and therefore hydrogen). Ammonia has a decent shot at being a shipping or aviation fuel too, but many of its alternatives need the same input of green hydrogen anyway so can share costs and scale with Ammonia production. As for intermittent renewables, we're approaching the point where we shift from mostly underproduced and only occasionally overprovisioned to them being near permanently overprovisioned and needing to find uses for that electricity that can be rarely halted to help the grid a few times a year. Hydrogen production fits the cost profile for long-term/seasonal storage that no lithium battery can hit, even if they drop in price even more than currebtly predicted.

ashtonkem 6y ago

There are some applications where energy density is far more important than energy efficiency. Airplanes come to mind. You would accept the pumping losses when it comes to filling a 737 with hydrogen, because you literally can’t make that plane work with batteries at this point in time.

kjaftaedi 6y ago
Glad to find this in the responses. Air transport is quite possibly the best use case for hydrogen fuel that I can think of, and likely the only way we'll get sustainable air travel in the near future.
- rootusrootus 6y ago
  Wouldn't it be easier to just work on efficient synthesis of jet fuel? Then we could just keep the rest of the infrastructure the same. Sometimes I wonder if that would end up being a solution for cars, too. It would certainly solve a few difficult edge cases that electrification will have a hard time overcoming.
  - mr_toad 6y ago
    > Wouldn't it be easier to just work on efficient synthesis of jet fuel? Some synthetic fuel production processes require hydrogen, so a cheap hydrogen source would still be useful.
rootusrootus 6y ago
> when it comes to filling a 737 That brings up an interesting point. I wonder how much of a factor fuel is in dictating the preferred size for an airliner. Maybe if the fuel economics and physics change, we'll see an evolution towards larger numbers of smaller point-to-point airliners.

dghughes 6y ago

Transportation aside hydrogen storage is great for its energy density. Storing it locally probably as a hydride. I'm picturing home use replacing oil or gas with hydrogen combined with a fuel cell. It would be great for high demand situations where solar plus a battery setup capacity was too low. For example winter little sun (low on the horizon too) and a long cold spell.

_fizz_buzz_ 6y ago

1.) There is already a 240 km hydrogen pipeline network in Germany (and probably in other countries as well) [1]. It connects chemical plants in the rhein-ruhr region. So there is already a huge market for hydrogen. These chemical plants will need hydrogen in the future. If we want to get away from using oil and gas and become CO2 neutral, we need a solution for those industries. 2.) I don't see air travel happening with batteries (except really short distances or really small planes). Weight is just too much of a factor in air travel and the energy density is just too far off with batteries. Hydrogen would maybe be a solution or some fuel that is synthesised from hydrogen. [1] https://industrie.airliquide.de/wasserstoffanlagen https://industrie.airliquide.de/wasserstoffanlagen

Hypx 6y ago

It should be pointed out that stationary systems can easily exceed 40% if we really wanted to. By combining heat and power generation you could push net efficiency out to 60% or higher. You also don't need to worry about compression or mobile storage saving you some more efficiency there too.

qPM9l3XJrF 6y ago

How about e.g. aeronautical applications where energy density is valuable?