[HN Gopher] Photocatalyst splits water into H and O2 at quantum ...
___________________________________________________________________
Photocatalyst splits water into H and O2 at quantum efficiency near
100%
Author : bookofjoe
Score : 444 points
Date : 2020-12-26 10:15 UTC (12 hours ago)
(HTM) web link (fuelcellsworks.com)
(TXT) w3m dump (fuelcellsworks.com)
| corty wrote:
| Interesting news, but it should be noted that quantum efficiency
| is only a part of overall efficiency. 100% quantum efficiency
| means that for 1 photon of sufficient energy you get 1 split
| H_2O. But it doesn't take into account which part of sunlight
| would be usable (there will be an energy cutoff) and what
| efficiency at channeling sunlight photons onto the catalyst your
| setup will have.
|
| Also, I'm missing the environmental conditions. If the process
| only works at >9000MPa and >9000K, it will be useless...
| thereisnospork wrote:
| It appears to be good science, but lousy engineering. To be
| fair to the original, the whole 'this research will save the
| planet shtick' is pretty much boilerplate for any paper[0].
|
| Photocatalytic H2 production will never be practical vs even
| boring old solar->electricity->Water-splitting. Literal acres
| of catalyst and transparent plumbing are not cheap or
| maintenance free, never mind that a hydrogen 'farm' producing
| mixed hydrogen and oxygen will make the Hindenburg look like a
| tea candle in comparison.
|
| re the conditions: the energy cutoff appears to be at around
| 370nm, so it essentially operates under UV light only, at
| atmospheric to a few bar pressure and close enough to room
| temperature.
|
| [0]e.g. Every nanotechnology paper is going to claim to all but
| revolutionize one or more of: drug delivery, cancer treatment,
| materials science, or my favorite, lithium batteries. Nine
| times out of ten though they are just taking <insert metal> and
| making <insert shape>: something which is useful to know how to
| do, but not typically revolutionary.
| mensetmanusman wrote:
| Too add: In materials research the term quantum efficiency, QE,
| implies that there are other efficiencies to consider.
|
| E.g. in the OELD space, it is talked about that the materials
| developed have near 100% QE. This is useful terminology because
| researchers know that there are other efficiency losses that
| need to be improved on, and that this one can now be considered
| 'finished' (although, some even look at other effects to try to
| go above efficiency 'maximums' that appear fixed at first
| glance: https://news.mit.edu/2019/increase-solar-cell-output-
| photon-...).
|
| Note: For OLEDs, although the QE is high, the light output
| efficiency is not very high due to internal light guiding
| effects.
| graderjs wrote:
| Other readers should not be discouraged by the above comment.
| Although it's disappointing to see this lazy skepticism as the
| top and longest lived comment.
|
| For a serious paper and a serious forum, I think a comment owes
| it to that seriousness and its readers to carefully investigate
| before displaying contempt.
|
| Under Methods:
|
| _Photocatalytic reactions_
|
| _Photocatalytic reactions were carried out in an overhead-
| irradiation-type glass vessel connected to a closed gas
| circulation system. Prior to each reaction, all air was
| evacuated from the reaction system and filled with Ar (about 1
| kPa unless otherwise noted). The suspension was subsequently
| irradiated using a Xe lamp (300 W, full arc). Evolved gases
| accumulated in the closed gas circulation system were analysed
| by gas chromatography (GC-8A, Shimadzu Co., thermal
| conductivity detector, Ar carrier gas, molecular sieve 5 A
| column). The STH efficiency was measured under simulated
| sunlight irradiation (AM1.5G, 9 cm2 illuminated area, solar
| simulator HAL-320, Asahi Spectra Co.). The STH efficiency was
| determined according to the following equation_
|
| We can clearly see it is 1 atmosphere, and reasonably assume
| it's "ambient temperature" plus 300 W Xe lamp irradiation. And
| it mentions nothing about "sunlight" but we can get consider
| the light spectra from the lamp. Comments should in future
| refrain from being inaccurate and lazily put together like the
| above. I think this goes doubly so for revolutionary and energy
| type tech that can be radically transformative. Good comments
| should push brave new science into the light, not drag it down
| into the dark of existing confirmation bias.
| x86_64Ubuntu wrote:
| Where did we get 1 atmosphere/101kPa from?
| graderjs wrote:
| Sorry the "1 atmosphere" should be "1 kPa" which is about
| 0.01 atmosphere. I didn't remember my chemistry units. Still,
| something you can get to with a normal vacuum pump in a lab.
| [deleted]
| antonvs wrote:
| The comment you replied to did not "display contempt." It
| pointed out a caveat for quantum efficiency, and that the
| linked article did not mention the environmental conditions.
|
| You could have contributed constructively, but you chose
| instead to bring down the tone. It is your comment that is
| not appropriate to a "serious forum."
| chrisweekly wrote:
| But the linked article did mention environmental
| conditions, justifying the "lazy" criticism.
| wizzwizz4 wrote:
| But you did bring down the tone in an otherwise excellent
| comment. Assume good faith, please.
| rat9988 wrote:
| I assume it was in good faith and that he didn't read the
| article. Lazy and good fatih aren't in odd.
| mootzville wrote:
| Commenting on another commenters comments as "bringing down
| the tone" in regards to their comments about another
| commenters comments "displaying contempt" is what really
| "brings down the tone" for me.
| arcticbull wrote:
| Thing is I at least didn't see the top post as bringing
| down the tone. They posited questions as folks here do
| and added to the topic. I for one would not have even
| known what to ask without the top comment.
|
| You assumed a lot of negativity and bad intent from the
| person and what they wrote that I didn't see.
|
| HN isn't meant to be a cheer squad for anything new, IMO.
| It's meant to be a forum for folks to discuss and people
| will have differing reactions but so long as they add
| something interesting, the comments are welcome, again
| IMO.
| cheschire wrote:
| I have been chastised (rightly so) by dang for name-calling
| when referring to someone's pedantry. I resisted at first
| because I did not call the person pedantic, merely referenced
| their pedantry.
|
| In this same way I see your wording as calling the GP "lazy"
| even though you did not use the specific grammatical form.
|
| If your post is not too old by the time you see this, I
| suggest finding another way to word your message to get the
| same point across.
| vendiddy wrote:
| I think deleting the word lazy, deleting the 2nd paragraph,
| and deleting the 2nd part of the last paragraph would get
| the same point across.
| rattray wrote:
| Thank you for sharing some of the environmental conditions of
| the test.
|
| I do remain curious how this might generalize to real-world
| efficiency...
| adrian_b wrote:
| Actually that comment was justified, because the article says
| that while the quantum efficiency is around 96%, the water
| splitting worked with ultraviolet light having wavelengths
| between 350 nm and 360 nm.
|
| Only a very small fraction of the solar light is ultraviolet
| light, so the usable efficiency of such a device is quite
| low.
|
| While this research result is very interesting as a
| demonstration of what can be done, it is very unlikely that
| this is a path that can lead to the best way of capturing
| solar energy.
|
| Either multijunction photovoltaic cells or thermal devices
| can capture around half of the total solar energy.
|
| If splitting water is desired, that problem can be solved
| separately, using electrical or thermal energy, and it should
| be able to reach similarly high efficiencies as with these
| photocatalysts.
|
| The combined efficiency of the 2 processes should be still
| far greater than the efficiency of direct water splitting,
| which is constrained by the lack of enough ultraviolet light
| in the solar spectrum.
| jjcm wrote:
| Is the wavelength restriction a blocker though? There's
| already use of quantum dot film to shift light wavelengths
| into spectrums more suitable for growing plants[1].
| Theoretically shouldn't this be able to be used to shift a
| larger percentage of the light spectrum into the 350-360nm
| range, resulting in a far higher actual yield?
|
| [1] https://ubigro.com/
| adrian_b wrote:
| Your example converts high-energy light (ultraviolet or
| blue) to low energy light (red). This process is easy and
| it can be done with quantum dots, as you say.
|
| The reverse process of converting red light to
| ultraviolet light, as it would be needed for this water
| splitting, is far more difficult and it has much lower
| efficiencies, especially when the input light has a low
| intensity. (The common green-light pointers convert
| infrared to green, but that works because the input is a
| laser beam with high intensity, so that optical media can
| behave non-linearly, and it still has a low efficiency).
|
| So no, wavelength conversion would not work.
|
| The only thing that would work would be to replace their
| semiconductor crystal with one having a much lower
| bandgap, like the silicon, gallium arsenide or cadmium
| telluride that are used in photovoltaic devices.
|
| However any such non-oxide semiconductors would be
| chemically unstable in contact with the nascent oxygen,
| so that would still not work.
| kelvin0 wrote:
| Another researcher I was following along these lines, and it
| faded away:
|
| https://en.wikipedia.org/wiki/Daniel_G._Nocera --- "Sun
| Catalytix, a startup for development of the artificial leaf. The
| company was bought by Lockheed Martin in 2014" ---- "In 2009,
| Nocera formed Sun Catalytix, a startup to develop a prototype
| design for a system to convert sunlight into storable hydrogen
| which could be used to produce electricity"
| dmix wrote:
| Do you mean talk of the tech faded away or the organization got
| consumed by the bigger firms R&D and you didn't hear much about
| it?
|
| Edit: found a good article on the topic
|
| > The hardest part of innovation often comes after you make the
| discovery, as Nocera learned.
|
| https://www.nationalgeographic.com/news/innovators/2014/05/1...
| buovjaga wrote:
| The lab is still active:
| http://nocera.harvard.edu/Publications2020
|
| Publications from 2020 include "Practical challenges in the
| development of photoelectrochemical solar fuels production
| (Sustainable Energy Fuels)"
| zootm wrote:
| Looks like the paper referenced is from May, if you have a
| subscription to Nature:
| https://www.nature.com/articles/s41586-020-2278-9
| hatmatrix wrote:
| And the accompanying overview/summary:
| https://www.nature.com/articles/d41586-020-01455-w
| NieDzejkob wrote:
| If you do not have a subscription to Nature: https://sci-
| hub.se/https://www.nature.com/articles/s41586-02...
| JorgeGT wrote:
| Nice, it appears that my parent's ISP is doing DPI and a MiTM
| attack to block Sci-Hub (and I _do_ have a subscription to
| Nature).
| traceddd wrote:
| Which ISP do you use?
| JorgeGT wrote:
| It's Vodafone Spain.
| tsimionescu wrote:
| Is it possible they are simply blocking DNS or the IP(s)?
|
| MiTM should be impossible on HTTPS - if they somehow
| obtained legitimate certs for sci-hub , you should really
| announce someone at Mozilla and/or Google.
| JorgeGT wrote:
| They appear to do deep packet inspection looking at the
| SNI and insert an invalid certificate from Allot,
| redirecting the connection to a very short "Vodafone
| can't show you this" website:
| https://pastebin.com/RHwPWBug
|
| It appears to work with ESNI activated in Firefox.
| Interesting to see these techniques in use...
| muxator wrote:
| > Por causas ajenas a Vodafone, esta web no esta
| disponible
|
| "Due to causes independent on Vodafone, this website is
| not available".
|
| How so? This is plain false. I bet they do not even
| inform their customers that the connectivity service they
| sell is endangered by Deep Packet Inspection.
| mcbits wrote:
| That just means the decision to block the site was made
| by someone outside of Vodafone. Assuming they face
| meaningful penalties for noncompliance, I wouldn't
| consider it false. But it would be nice if these kinds of
| messages identified who is to blame.
| mhh__ wrote:
| Virgin Media give you a message for blocked porn, but not
| the VPNs they stop you accessing.
|
| It's quite insidious - the VPN blocks are textbook
| government overreach.
|
| If we ever have a written constitution in the UK we need
| rules stopping the government fucking about with this
| stuff (As it seems to be the entropic end-state of all
| policy to protect the children)
| bawolff wrote:
| Sometimes people use the phrase mitm loosely to mean
| sniffing SNI and then blocking the connection in some
| fashion.
| JorgeGT wrote:
| Apologies if the usage is incorrect. They appear to
| indeed sniff the SNI and then inject a one-line website
| with a self-signed certificate:
| https://pastebin.com/RHwPWBug
| dwightgunning wrote:
| Thanks both for taking the time to acknowledge and
| explain the subtlety. Helps somebody like me who's
| casually following along to better understand both
| scenarios.
| IncRnd wrote:
| That isn't true except for the case of cert pinning. This
| sort of MiTM (or redirection at the very least) reglarly
| happens from employers, isps, and many others.
| perlgeek wrote:
| my ISP's DNS resolver just returns NXDOMAIN for that.
| $ dig @8.8.8.8 sci-hub.se. +short 186.2.163.219
| semi-extrinsic wrote:
| what happens if you try the .st TLD?
|
| .se is Sweden, I was surprised to see that they haven't
| taken down sci-hub.
| perlgeek wrote:
| sci-hub.st works here (Telekom in Germany).
| Yetanfou wrote:
| Use the Telegram bot @scihubot, that will probably evade
| the DPI trap. Just send the DOI or the full article name to
| this bot and you'l either get a PDF back or a message about
| the article not yet being in the database.
| [deleted]
| kseistrup wrote:
| The original article at
| https://www.nature.com/articles/s41586-020-2278-9 is
| unfortunately behind a paywall.
| daenney wrote:
| Over here: https://news.ycombinator.com/item?id=25542822
| redis_mlc wrote:
| Usually it's my favorite of (+):
|
| (+) diamond anvil pressure cell at 1 million atmospheres.
| tim333 wrote:
| The abstract of the paper makes it sound good:
|
| >Overall water splitting, evolving hydrogen and oxygen in a 2:1
| stoichiometric ratio, using particulate photocatalysts is a
| potential means of achieving scalable and economically viable
| solar hydrogen production. To obtain high solar energy conversion
| efficiency, the quantum efficiency of the photocatalytic reaction
| must be increased over a wide range of wavelengths and
| semiconductors with narrow bandgaps need to be designed. However,
| the quantum efficiency associated with overall water splitting
| using existing photocatalysts is typically lower than ten per
| cent1,2. Thus, whether a particulate photocatalyst can enable a
| quantum efficiency of 100 per cent for the greatly endergonic
| water-splitting reaction remains an open question. Here we
| demonstrate overall water splitting at an external quantum
| efficiency of up to 96 per cent at wavelengths between 350 and
| 360 nanometres, which is equivalent to an internal quantum
| efficiency of almost unity, using a modified aluminium-doped
| strontium titanate (SrTiO3:Al) photocatalyst3,4. By selectively
| photodepositing the cocatalysts Rh/Cr2O3 (ref. 5) and CoOOH
| (refs. 3,6) for the hydrogen and oxygen evolution reactions,
| respectively, on different crystal facets of the semiconductor
| particles using anisotropic charge transport, the hydrogen and
| oxygen evolution reactions could be promoted separately. This
| enabled multiple consecutive forward charge transfers without
| backward charge transfer, reaching the upper limit of quantum
| efficiency for overall water splitting. Our work demonstrates the
| feasibility of overall water splitting free from charge
| recombination losses and introduces an ideal
| cocatalyst/photocatalyst structure for efficient water splitting.
|
| Not so sure about the fuelcellsworks article clickbaiting up the
| 'quantum' bit when all it means is one photon splitting one H2O.
| Retric wrote:
| Splitting H20 also means a free floating oxygen atom which will
| eventually form O2 and produce waste heat.
|
| The quantum efficiency is therefore likely a meaningless number
| in practice. Though it's handy from a scientific perspective.
| ben_w wrote:
| "Quantum efficiency" is a specific and long-used term, even
| though the word "quantum" (like "exponential") gets abused for
| clicks: https://en.m.wikipedia.org/wiki/Quantum_efficiency
| wincy wrote:
| You mean that my loan originator telling me housing prices
| would be increasing exponentially was hyperbole? Because I'm
| really counting on my 256 thousand dollar home investment
| being worth 65536 million next year. Drove me crazy all
| throughout the house buying process, it seems like every
| realtor says stuff like that.
| krastanov wrote:
| To be fair, exponential growth can have a rather large
| time-constant and it still is exponential. Most
| valuation/inflation/stock market/house market plots that
| span more than a decade or two are indeed logarithmic plots
| because much of these curves indeed follow exponentials.
| asdfasgasdgasdg wrote:
| Exponential growth is not necessarily fast growth. If r is
| .00000001 and the period is one year, then the curve would
| look flat on any human timescale.
| studius wrote:
| > all it means is one photon splitting one H2O
|
| It's not one H20. I read the graphic as:
|
| 110 H30+ + 100 OH- -- 350-360nm UV light + Al-doped SrTiO3
| selectively coloaded with Rh/Cr2O3 + CoOOH --> 210 H20 + 5 H2
|
| That looks like if it were paired with a cathode, you could
| take water and produce H2 more efficiently, but you'd need to
| keep the H+ sufficiently high or continue to supply it with
| more water, otherwise you develop higher OH- and H2O2 elsewhere
| in the solution from the H+ depletion, and that'll probably
| create some O2, but not at the rate you would with
| electrolysis, because the catalyzed reaction above would itself
| create a higher H+ environment, which feeds into itself from
| the H3O, but the H2 gas is escaping, depleting the H2 from the
| solution whereas the O2 is not gathering and escaping like that
| as much.
|
| So, you could efficiently turn H2O into H2 source for a fuel
| cell.
|
| But, you could also use this to make water more basic.
|
| More detail:
|
| Water is naturally a solution of H2, O2, H+, OH-, O--, H20, and
| H3O+, H2O2--. Except for H+ and O--, those are splitting and
| recombining most of the time while in liquid state, because the
| various ions in water and larger structures, etc. act as
| catalysts to the various reactions.
|
| With light and the catalysts, the reaction above would seem to
| continue for quite a while, since the reaction produces H+
| which will combine with surrounding H2O to product H3O.
|
| Eventually, you're left with a greater concentration of OH-
| elsewhere in the solution (though surface of the catalyst near
| the reaction and the area above it that the H2 flows through
| would be more acidic). The reaction could stop if the
| availability of H3O and H2O would become too low, and at that
| point, the water would be more basic, because you wouldn't have
| sufficient free H+.
| graderjs wrote:
| People are focusing on the direct (STH - solar-to-hydrogen)
| efficiency) which is low.
|
| Instead, this paper introduces a materials engineering advance
| in a prototype UV-absorbing catalyst, that pushes EQE values to
| maximum, and suggests similar can be done to an existing
| visible-absorbing catalyst, to give an STH of 10%, which is
| very high for these durable, cheap catalysts. I got this from a
| quick reading of this paper and related papers.
|
| Relevant section:
|
| _Recently, Ta3N5 and Y2Ti2O5S2 have been reported to split
| water into hydrogen and oxygen under visible light. These
| materials absorb visible light with wavelengths of up to 600 nm
| and 640 nm, respectively, and the STH efficiency can reach 10%
| once the EQE is improved to a level similar to that of
| SrTiO3:Al. The suitable photocatalyst design presented here
| should provide impetus to the development of particulate
| semiconductor photocatalysts for practical solar hydrogen
| production from water._
| [deleted]
| jojobas wrote:
| The caveat is that the portion of solar energy between 350 and
| 360 nm is very little.
| [deleted]
| missurunha wrote:
| They only tested in the range from 350 to 380nm [1]. With
| wave lengths under 370nm the efficiencies are quite high; at
| 380nm it falls to 33,6%. That could either mean that the
| catalyst works well with light at small wavelengths or that
| it only works at this specific range.
|
| [1] https://www.nature.com/articles/s41586-020-2278-9
| ginko wrote:
| So will this produce hydrogen and oxygen gas separately or a 2:1
| mix of the two (i.e. oxyhydrogen)?
| __MatrixMan__ wrote:
| Is anyone familiar enough with the chemistry of creating
| synthetic hydrocarbons to comment on whatever bottleneck is
| preventing it from being mainstream?
|
| It seems like synthetic gasoline and synthetic propane would be
| ideal energy sources (and that cheap hydrolysis would be the
| starting point), so I figure there must be a reason that people
| don't often talk about it.
| aaronblohowiak wrote:
| It has been scaled up.
| https://en.m.wikipedia.org/wiki/Sabatier_reaction
|
| The first commercial synthetic gas plant opened in 1984 and is
| the Great Plains Synfuel plant in Beulah, North Dakota.[9] It
| is still operational and produces 1500 MW worth of SNG using
| coal as the carbon source. In the years since its opening,
| other commercial facilities have been opened using other carbon
| sources such as wood chips.
| imtringued wrote:
| We don't have an overabundance of low carbon energy that would
| justify the investments. There is also the problem that
| capturing CO2 is only economic at a point source. The
| fundamental problem is that the concentration of CO2 in the
| atmosphere is too low for direct air carbon capture.
| toast0 wrote:
| It's not sexy and the cost is usually too high relative to
| fossil fuels.
|
| I personally think it would make a lot of sense to develop
| further. Conventional fuels are very convenient, and if you
| produce them synthetically without extracting resources from
| underground deposits, there's a lot less climate impact. It
| wouldn't eliminate tailpipe emissions, but it might
| significantly reduce sulfur emissions for example.
|
| Long distance transportation is always going to be a challenge
| for EVs, that synthetic fuels could handle if they're
| economical to produce and sell.
| yholio wrote:
| 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.
| zbrozek wrote:
| 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 wrote:
| >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.
| imtringued wrote:
| >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.
|
| I think you are missing something or are lacking in
| creativity. By this logic we shouldn't use batteries either
| because the energy you get out of the batteries is always
| less than the energy you put in. Also, where are you
| introducing additional natural gas? It's merely meant to be
| used as a temporary storage technology to allow a greater
| renewable share.
|
| To be more blunt. Investments into storage technologies
| allow more renewables to be introduced into an electric
| grid. Nobody cares about the efficiency because that was
| never the goal in the first place. The goal is reducing the
| usage of fossil fuels to an absolute minimum and that means
| using less natural gas, despite the inefficiency.
| zbrozek wrote:
| > Hydrogen really doesn't like to be stored though. It also
| ruins any storage vessel it is kept in long term.
|
| It's true that it's the smallest atom, but it's not the
| smallest molecule. Helium is more prone to escapement since
| it's not diatomic. Doing a bit of research it looks like
| aluminum is actually a fine container for pressurized
| hydrogen (low permeation rates, low embrittlement). You do
| need to reinforce it (e.g., composite wrapping) if you want
| to go to high pressures.
|
| >and this makes less since.
|
| FYI, s/since/sense
|
| I think you're over-indexing on efficiency. That's not the
| only metric that influences success. Suppose that we have
| an overabundance of intermittent sources of electricity
| (e.g., wind and solar). Right now there's not much you can
| do to store it. Batteries are great for smoothing demand
| over hours or days, but they're quite far from smoothing
| demand over weeks or months.
|
| So if you're able to cheaply overproduce electricity, it
| doesn't really matter if your storage process is not
| particularly efficient. Even at fairly low efficiencies,
| it's more useful than throwing it away so long as the
| capital cost of the conversion equipment is low enough to
| tolerate the intermittency.
|
| As for the cryogenic storage adding an additional
| efficiency hit - yes, correct. But there's an intercept of
| marginal cost, storage density, and efficiency where it
| will be economical to do it. The technology question is if
| we can deliver that intercept at a lower total cost than
| other alternatives.
|
| One thing that's really attractive about hydrogen is that
| the costs are not the processed media. Batteries are full
| of expensive to mine and refine materials and their storage
| capacity is more-or-less directly tied to the quantities of
| used materials. With hydrogen production the media are
| water and space, both of which are almost free in many
| contexts. Vehicles aren't really one of them because volume
| is precious, but for stationary applications it's a
| completely different story.
| _fizz_buzz_ wrote:
| 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
| konschubert wrote:
| 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.
| ZeroGravitas wrote:
| 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.
| rarefied_tomato wrote:
| Simple counterargument: you can't make a large electric plane.
| The energy density of a battery is too low.
| yholio wrote:
| 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 wrote:
| 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 wrote:
| 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"
| sunstone wrote:
| A project has been announced to move energy from the
| Australian outback to Singapore, a distance of over 3000km
| mostly underwater.
| [deleted]
| samstave wrote:
| Less pollution in the future and less need for lithium?
|
| So maybe that's a better trade off for the planet.
| atlgator wrote:
| As long as we have coal plants powering our electrical grid we
| should seek alternatives that would replace or reduce reliance
| on them.
| bananabreakfast wrote:
| 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.
| laumars wrote:
| 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).
| DarmokJalad1701 wrote:
| > 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 wrote:
| That's interesting. I wasn't aware that was now possible
| with battery tech.
|
| Thanks for the explanation.
| bananabreakfast wrote:
| check out 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.
| _jahh wrote:
| if anything it's the environmental and social impact of the
| mining of the minerals vs the disposal.
| ashtonkem wrote:
| 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.
| rootusrootus wrote:
| > 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.
| kjaftaedi wrote:
| 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 wrote:
| 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 wrote:
| > 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.
| adamcstephens wrote:
| How should we obtain enough electric generation to offset the
| lost of hydrocarbons?
| dghughes wrote:
| 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.
| ed_balls wrote:
| 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.
| ed25519FUUU wrote:
| 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 wrote:
| Only aircraft care, though. Fuel weight in other applications
| is basically a non-issue except for really niche gadgets.
| yholio wrote:
| > 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.
| [deleted]
| phkahler wrote:
| 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.
| bumby wrote:
| 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.
| dmead wrote:
| 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 wrote:
| 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.
| benlivengood wrote:
| 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.
| eggy wrote:
| 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!
| TheRealPomax wrote:
| 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.
| Aerroon wrote:
| 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.
| bananabreakfast wrote:
| 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.
| deadc0de wrote:
| Also ICE engines themselves are pretty heavy compared to
| electric motors and require heavy gearboxes and shafts.
| Gibbon1 wrote:
| My back of the envelope calcs say that if batteries
| energy density increases by 30-50% the weight penalty for
| electric cars disappears. It's a fuzzy line because it
| depends on the cars range.
|
| Difference between electric and gasoline cars. With a gas
| car the marginal cost of extra range is low. With
| electric it's high. With gas cars the marginal cost of
| extra HP is high where with electric it's low.
| yholio wrote:
| 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/documen
| ts/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 wrote:
| Electric engines convert those Megajoules to actual motion
| much more efficiently than combustion engines.
| gpapilion wrote:
| 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 wrote:
| > 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 wrote:
| 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 wrote:
| 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.
| ogre_codes wrote:
| > 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.
|
| There are 2 types of convenience.
|
| - Being able to fuel up quickly on a long trip
|
| - Having your fuel tank full at the beginning of every single
| trip.
|
| Hydrogen fuel cells (and combustion engines in general) are
| better only for the former case. Since most people drive less
| than 300 miles most of the time, it's hard to argue a car
| optimized for longer trips is more convenient for most
| drivers.
| ttul wrote:
| 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 wrote:
| 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 wrote:
| I believe OP is thinking more municipal pipes that feed
| individual buildings rather than a distribution pipeline
| like Keystone XL.
| yholio wrote:
| 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.
| zbrozek wrote:
| It looks like you can blend something in the neighborhood
| of 10-15% hydrogen into the existing natural gas
| infrastructure without negative consequence. That's not
| game changing, but it's a significant environmental
| improvement if you're using renewables to produce it.
| It's a fine way to utilize daily or even seasonal
| renewables overproduction in a useful way without blowing
| up tons of existing infrastructure. Many diverse steps -
| some small, some large - are needed to get ourselves to a
| carbon negative lifestyle.
| iso1210 wrote:
| > Aside from blending small amounts on hydrogen in
| existing methane feeds
|
| What's "small"?
|
| 20% hydrogen on existing grid in place now: https://www.t
| heguardian.com/environment/2020/jan/24/hydrogen...
|
| 100% hydrogen trial over next few years:
| https://www.msn.com/en-us/news/technology/scottish-homes-
| wil...
|
| Hydrogen has suddenly skyrocketed up the agenda in Europe
| this year. There is a pressure group called Hydrogen
| Europe (which oddly doesn't even have a wikipedia page)
| which comprises companies like BP, Shell, Total, Equinor,
| Repsol, Engie, OMV, PKN Orlen, Hellenic Petroleum, and
| many more. At the same time almost 100% of hydrogen used
| in europe comes from oil.
|
| It concerns me how much government subsidy (both cash and
| regulations) is being pushed into hydrogen.
|
| https://www.thisismoney.co.uk/money/markets/article-89703
| 77/...
|
| "Hydrogen companies were given a boost this week after
| the Prime Minister vowed to inject PS500million to 'turn
| water into energy' as part of a 10-point plan for
| Britain's green recovery.
|
| However, critics say the targets are nowhere near enough
| compared to Germany's and France's respective plans to
| invest EUR9billion and EUR7billion in hydrogen."
| mojomark wrote:
| >>To produce Hidrogen, you need electric energy, or some
| very hot source that could be turn to electricity at a
| high efficiency.
|
| This is not a true statement... Aluminum alloys readily
| liberate H2 from H20 at room temperarure (an exothermic
| reaction generating roughly equal parts thermal and
| chemical potential energy - both of which of course can
| be used for work) [1].
|
| The oxidized aluminum is environmentally benign and can
| be recycled by applying more energy to deoxydize the
| product. The 'purification' process is ultimately where
| the useful energy comes from. The energy to power the
| purification can come from any number of sources - but as
| good stewards, we opt for clean energy sources. Al
| smelting historically produced a lot of carbon, but
| thanks to R&D by Apple, there are new carbon-free
| alternatives for this process [2].
|
| At my company we are researching application of this
| energy infrastructure loop for powering ships (where
| source water is abundant). Essentalially, the Al+ is your
| fuel (battery), and from a volumetric energy density
| perspective (important for ships), you can store about 2X
| as much as gasoline/diesel - and way better than
| liquified or compressed H2 storage. However, on a mass
| energy density perspective (important for automobiles),
| it is a bit worse (heavier) than hydrocarbon fuels. Again
| though, each application has it's own constraints when
| considering an energy storage medium.
|
| The automotive or civil sectors aren't the only use-cases
| for hydrogen fuel cells. One needs to take a look at all
| sectors to really grasp the global impact. A large part
| of my job is to explore this big-picutre aspect, because
| we need to understand the long term infrastructure
| stability/availability of potential "clean" energy supply
| chains, and it's VERY complex when you consider process
| efficiencies over the entire supply chain, raw material
| abundance and regeneration
| potential/economics/environmental impacts/speed,
| geopolitical forces affecting supply chains, the list
| goes on and on (and on).
|
| H2 is an interesting "energy storage" option and it will
| certainly continue to be researched and applied broadly.
|
| 1. PDF - https://www.google.com/url?sa=t&source=web&rct=j
| &url=https:/...
|
| 2. https://www.apple.com/newsroom/2018/05/apple-paves-
| the-way-f...
| rini17 wrote:
| 100% of aluminium is made with electrical energy...
| lowercase1 wrote:
| 75 kWh doesn't take a few hours with a supercharger. Doing
| similar with hydrogen is probably a similar level of
| infrastructure.
| manmal wrote:
| I charge my electric Hyundai with a normal power outlet, and
| every once in a while I fast-charge it. 99% of the time
| that's good enough already. If we're going by convenience,
| plugging in at home is probably more comfortable than driving
| to a gas station, waiting 5 minutes, paying, and driving
| back.
| pdonis wrote:
| _> Hydrogen isn 't aiming to be as efficient as batteries.
| It's assuming to be as convenient as gasoline_
|
| And it won't be. H2 is terrible for convenience of handling
| compared to gasoline. Handling liquid H2 is a nonstarter, it
| liquefies at 21 K at atmospheric pressure; cryogenics like
| that are not convenient at all. Gaseous H2 will escape
| through every tiny gap in whatever containment setup you
| choose, plus it's highly flammable, much easier to ignite
| inadvertently than gasoline.
|
| And to top it all off, at the end of the day, its available
| chemical energy per unit mass is only two to three times that
| of liquid hydrocarbons. That's simply not enough of an
| advantage to overcome all the downsides.
|
| What H2 _can_ be used for is to _make_ liquid hydrocarbons,
| through various chemical processes.
| m4rtink wrote:
| Hydrogen is also notoriously low density, even in liquid
| form. It embritles metals on contact. Hydrogen fires are
| invisible during the day (if you see rocket engineers
| walking around with broom pointed forward in front of them,
| that's why).
|
| Personally I count on hydrogen for high energy space
| propulsion (either chemical with oxygen or alone in a NERVA
| for NTR) as otherwise it's IMHO too much of a headache to
| work with in practice.
| cmrdporcupine wrote:
| Except that as we keep trying to point out, 90% of EV
| charging occurs overnight at home, or at work during the day.
| Yes, that does not cover all cases for all people, but it
| covers a large part and the scenario people keep bringing up
| is the exception to the rule that would only take place if
| people were on road trips or there was no charging at their
| residence or work.
|
| Obsessively talking about charging times is a frame of
| reference influenced by decades of driving ICE vehicles. And
| frankly the hydrogen vehicle thing also seems like it is
| heavily influenced by this mindset as well.
|
| I can't make or fill gasoline (or hydrogen) at home. After
| years of "refueling" my Volt this way, I'd have a hard time
| giving up my "gas butler" that gives me a full "tank" every
| time I leave my house, and having to return to going to gas
| stations sounds highly unpleasant and very inconvenient.
| lodovic wrote:
| But there are a few caveats:
|
| - The power to charge the EV is drawn from the grid
|
| - Batteries are heavy, so you cannot scale up batteries for
| range
|
| - These batteries require a lot of lithium mining
|
| Given these, I would definitely prefer the hydrogen
| solution.
| yholio wrote:
| There is no fundamental physics reason to use lithium,
| it's just the current best technological node. There are
| many technologies that are very promising in the lab,
| like carbon nanotubes, iron and sodium ion, aluminum-air
| etc. There is massive research in this area and if none
| of these technologies turn out to be economically
| superior to Li-ion in the near future, then they will
| certainly be available if, for environmental reasons,
| lithium becomes expensive.
|
| https://www.pocket-lint.com/gadgets/news/130380-future-
| batte...
| cmrdporcupine wrote:
| - The grid where I am is 90% non-CO2 emitting; nuclear
| and hydroelectricity with natural gas supplimenting it.
| We phased out the last of the coal plants 15 years ago.
| More places should, the air quality in the whole province
| improved markedly after.
|
| - I drive a car with a small 14kWh battery, and a backup
| ICE for when I need it. 90% of my miles are electric. I
| don't understand why this model isn't more popular. I see
| no need to drag around a 60kWh battery "just in case" I
| need that extra range.
|
| - Lithium isn't the huge environment/social problem
| really. Basically big evaporation ponds in desert areas.
| There's even some work being done to pull lithium out of
| abandoned oil wells in some locations. Some of the other
| components are a problem, such as Cobalt in some
| formulations. But all these formulations can be played
| with. And they are one-time for the whole vehicle, rather
| than requiring continual extraction. And can be recycled.
| Can't recycle petroleum or hydrogen.
|
| Meanwhile the only practical sources for producing
| hydrogen require fossil fuels, typically natural gas, and
| end up emitting CO2. Emitting CO2 is not necessary for EV
| usage. But most practical sources of hydrogen do. And the
| efficiency is far lower.
| creddit wrote:
| > Except that as we keep trying to point out, 90% of EV
| charging occurs overnight at home, or at work during the
| day.
|
| This isn't a good comparison at all. You're looking at the
| set of people who looked at the operational requirements
| for EVs and said "yes, this works for my needs" and then
| looking at how those needs are met. What you would really
| want to do is compare the operational requirements for EVs
| and the general usage of motor vehicles to see what
| proportion of the general usage of motor vehicles can be
| replaced by EVs and their operational requirements.
|
| EDIT: Even further, you would really want to know about the
| value of different modes of usage as well. So, for example,
| it is possible that users value edge case usage (such as
| very long trips) much, much higher than they do day-to-day
| usage and so still you could meet 90% of general motor
| vehicle usage with EVs at the same convenience but if the
| remaining 10% was far more valuable to end users and the
| inconvenience too high, it might still not be reasonable.
| ogre_codes wrote:
| > So, for example, it is possible that users value edge
| case usage (such as very long trips) much, much higher
| than they do day-to-day usage and so still you could meet
| 90% of general motor vehicle usage with EVs at the same
| convenience but if the remaining 10% was far more
| valuable to end users and the inconvenience too high, it
| might still not be reasonable.
|
| How much do you weigh the inconvenience of being 10
| minutes late for an appointment because you had to make
| an unplanned fuel stop?
|
| How much do you value 100s of unneeded fuel stops
| interrupting your life?
|
| Fortunately, it's not necessarily an either/ or. You can
| buy an EV for 99% of driving and just rent an ICE car
| when you need to road-trip.
| creddit wrote:
| Totally. I'm not taking a side here. I think it's a
| really complicated issue. I'm excited for EVs and
| optimistic about their future but we have to be real
| about trade offs when considering other possibilities.
| jklinger410 wrote:
| People don't know what they want. The fact is, the
| infrastructure for renting gas vehicles for long drives
| is already in place, and 99% of driving is short and
| local.
|
| Thinking about "how much users value x" based on the
| CURRENT PARADIGM is a constraint to progress, and doesn't
| help predict very much at all. Consumer habits change.
| ogre_codes wrote:
| > The fact is, the infrastructure for renting gas
| vehicles for long drives is already in place, and 99% of
| driving is short and local.
|
| Exactly.
|
| If you are going on a long trip, renting or renting plus
| flying is likely best. If you are traveling 1200 miles,
| do you really want to drive for 20 hours solid? I've done
| it and it mostly sucks.
| vmception wrote:
| > What you would really want to do is compare the
| operational requirements for EVs and the general usage of
| motor vehicles to see what proportion of the general
| usage of motor vehicles can be replaced by EVs and their
| operational requirements.
|
| Okay, has this been done by anyone? Something that shows
| current limitations of the infrastructure and projected
| mitigation of those?
| toomuchtodo wrote:
| A quick Google search doesn't find anything official from
| NREL or similar DoE labs, but I'm mobile so my search is
| quick and not comprehensive.
|
| The average American round trip commute is under 40
| miles. Longer commutes can be accommodated with financial
| incentives and legal requirements for employers to
| provider EV chargers on prem (with pass through billing
| for the power, or providing it for free). Anything beyond
| that (high daily mileage outliers) are served by long
| range EVs and Fast DC charge networks.
| iso1210 wrote:
| > This isn't a good comparison at all. You're looking at
| the set of people who looked at the operational
| requirements for EVs and said "yes, this works for my
| needs" and then looking at how those needs are met. What
| you would really want to do is compare the operational
| requirements for EVs and the general usage of motor
| vehicles to see what proportion of the general usage of
| motor vehicles can be replaced by EVs and their
| operational requirements.
|
| The vast majority of journeys and days overnight charging
| of a tesla style car is fine. The average driver
|
| 1) Spends 55 minutes a day behind the wheel
|
| 2) Drives 29 miles a day
|
| https://solarjourneyusa.com/EVdistanceAnalysis7.php
|
| "93% of all vehicle-days show a total distance below 100
| miles. It is important to note that only vehicle-days are
| included where the cars were used that day"
|
| A car with a 300 mile range covers almost all drivers for
| almost all uses.
|
| So you're down to whether the downsides of owning and
| operating a gas-fueled car outweighs the downsides of an
| electric car (having to hire a gas one for occasional
| long trips)
|
| As more and more people move to electric, there are fewer
| and fewer customers for gas stations, reducing the number
| around, and reducing the utility of a gas car even more.
| The costs of repair become higher, and the cost of the
| car in the first place will increase as economies of
| scale tip the other way.
| yholio wrote:
| I think the point made here is that those very
| requirements are tailored around a ICE world. If, say,
| your city bus network is designed so that each driver can
| make a 5 minute stop at terminus and fill up when
| required, of course pushing an electric bus into that
| will create 1-2h gaps in service and be "not fit to
| operational requirements". But it's a simple exercise to
| shift things around so that all recharging is done in low
| demand periods and all your fleet is online during rush
| hour.
|
| The bottom line: electrics are quickly overcoming the
| 1000Km/charge barrier, in the next 10 years it will
| probably become the norm. That's a charge level that can
| last you a full day in almost any conceivable usage mode,
| so it can cover 99% of real world tasks.
|
| Sure, there will still be very specialized tasks where 2
| hours of downtime per day is unacceptable, or some fresh
| produce delivery route that requires 36 hours non stop
| driving by a shift of truckers. But that would be
| negligible in the grand scheme of things.
| elihu wrote:
| The other possible option to work around range issues
| with electric vehicles is to electrify our major highways
| so that battery capacity is no longer a concern. That
| would require expensive infrastructure upgrades and new
| standards for how to charge a moving vehicle, but it
| would mean vehicles could be substantially lighter and
| less expensive.
| bumby wrote:
| > _36 hours non stop driving by a shift of truckers. But
| that would be negligible in the grand scheme of things._
|
| Can you elaborate on why you'd consider trucking to be a
| negligible edge case? What I could find online shows it's
| over 40% of commercial miles and over 60% of transport
| for delivered goods.
| ogre_codes wrote:
| Trucking is 40% of commercial miles. Most trucks are
| parked for hours/ day so the driver can sleep. It'll be
| interesting seeing how this changes as autonomous driving
| becomes more common.
| bumby wrote:
| Some trucking companies are using a "local" model where a
| driver will drive 4 hours one way, drop off the trailer
| to another driver for the next leg, and pick up a trailer
| to drive back home to be more efficient
| adwn wrote:
| You left out this important qualifier in your quote: _"
| [...] some fresh produce delivery route that requires 36
| hours [...]"_. yholio was talking about a particular
| niche case, not about trucking in general.
| bumby wrote:
| Ahh, ok, I read it as two separate cases (produce
| delivery and long haul trucking). Thank you for
| clarifying
| koolk3ychain wrote:
| Fast charging is also arguably the _least_ environmentally
| concious way to charge any electric vehicle.
|
| A) fast charging causes battery degradation at least 3-5x
| as fast as charging at or below the nominal "C" rating of a
| given cell or amortized individual cell rating. This means,
| in the next 10 years, more batteries have to be produced,
| more lithium has to be mined and more Tesla parts have to
| be shipped on diesel powered vehicles. [0][1]
|
| B) it uses more power and places more demand on the grid,
| hence you're burning more coal in order to meet the demand
| curve and incur a larger transitional period in production
| which means more fossil fuels burned, more energy lost to
| conversion and at the end of the day more Co2 in the air.
| [2]
|
| 0 - https://cleantechnica.com/2017/07/09/tesla-limiting-
| supercha...
|
| 1 - https://cleantechnica.com/2020/01/12/is-it-true-that-a-
| tesla...
|
| 2 - https://afdc.energy.gov/files/u/publication/ev_emission
| s_imp...
| BobbyJo wrote:
| Yes, EVs are a great 99% solution. The problem is people
| aren't willing to own a second car to take care of the
| other 1%, so they need their car to be a 100% solution.
| Most of my friends take weekend road trips to camp or visit
| friends in other cities, and EVs just aren't capable of
| those use cases yet.
| Finnucane wrote:
| No car ever made is a 100% solution, and many people do
| own multiple cars already.
| bananabreakfast wrote:
| This is 100% false and hasn't been true for a long time.
|
| A Tesla can easily take a road trip the same as any ICE
| vehicle. I've personally driven one across the country.
| Supercharging along the way now takes the same amount of
| time as any normal stop for gas.
|
| EVs are already better than a 100% solution because
| electricity is far cheaper than gas and you can fill up
| at home.
| new_realist wrote:
| I've owned three Teslas and I can tell you that road
| tripping isn't at all as convenient in a Tesla as an ICE.
| rootusrootus wrote:
| I agree, though I'd concede that we enjoy taking the
| Tesla on road trips because our kids are young. Stopping
| at the McDonalds next to the supercharger for a restroom
| break, sometimes lunch, or a romp in the play area for
| half an hour works really well for us. If our definition
| of roadtripping was drive-pee-drive-pee-drive-pee-drive
| with no real rest stops, it would definitely be faster to
| take our pickup (the only gas vehicle we have left).
| BobbyJo wrote:
| I can tell you quite definitively that a tesla with the
| maximum range possible will still not be able to get you
| to and from a great deal of small cities and camp grounds
| in the US, especially if you live outside California.
| ogre_codes wrote:
| If you can afford a Tesla, renting a car for 1 week a
| year isn't a big burden.
| BobbyJo wrote:
| Yet another reason EVs aren't the dominant market yet.
| ogre_codes wrote:
| Likely the single biggest reason.
| hakfoo wrote:
| I'm surprised nobody does a product that's an EV lease
| plus some prepaid credit every month for a rental
| service, so for the one day a month you need a
| conventional petrol car, it's already budgeted for.
|
| Hell, you could generalize it to small petrol cars too. I
| suspect most of us "overbuy" larger and more capable
| vehicles for the one day a month we need something bigger
| than a Mirage.
| linuxftw wrote:
| Problem 1) Many people don't live in houses. Problem 2)
| Free charging at work or elsewhere ends once a significant
| share of people utilize it Problem 3) electric grid can't
| handle the amount of capacity needed, not by a long shot.
|
| If petroleum didn't already exist we'd be trying to create
| it.
| hinkley wrote:
| There are quite a few urban areas with single occupant
| houses but without driveways. Most people wouldn't want
| to install a charger out in their parking strip, on
| general principle - too exposed. Running high current
| wires out into the front yard and under the sidewalk
| would also be a mess.
|
| And that's all ignoring the fact that the city owns the
| parking strip, not you, and I don't think they're going
| to be interested in having that kind of equipment in
| their space.
| rootusrootus wrote:
| > I don't think they're going to be interested in having
| that kind of equipment in their space.
|
| Aren't some cities (LA comes to mind) installing level 2
| chargers along the street?
| ogre_codes wrote:
| > If petroleum didn't already exist we'd be trying to
| create it.
|
| You are forgetting about the power of NIMBY!
|
| If gasoline weren't already a vital piece of
| infrastructure, nobody would allow a gas station to be
| built in their neighborhood. Any time someone tried to
| build one, the pile of litigation would bury the
| prospective builder. This is already an issue and our
| society has largely taken the risks of having (literal)
| toxic waste at the end of their block.
| hakfoo wrote:
| I could see an interesting appeal in focusing on getting to
| a 1-hour or 30-minute charge time. because that allows for
| some structural changes to an entrenched business model.
|
| The current gas-station/convenience-mart ecosystem is
| designed around a 5-minute or so petrol fueling cycle.
| There's nothing they offer that will keep you productively
| occupied for a hours-long charge cycle.
|
| A 30-minute or hour charge cycle, in contrast, is long
| enough to perform errands-- I could see a large number of
| supermarkets, strip malls, big-box shops, and restaurants
| interested in offering 1-hour charging stations. You can
| offer cross-promotions (spend $100 in store and your charge
| is free) and you have captive customers who are likely to
| wander the aisles a bit longer/order an extra coffee or
| dessert if they know they need to wait another 10 minutes
| for their charge to complete. Maybe the no-garage apartment
| dweller does his charging when he goes for his weekly
| grocery run.
| pathseeker wrote:
| >Except that as we keep trying to point out, 90% of EV
| charging occurs overnight at home
|
| Most people don't buy vehicles for 90% of the use-cases.
| They buy something that does everything they normally
| expect a car to do, which includes a long road trip every
| year or so. Maybe driving to a favorite campground 200
| miles away, etc.
|
| The reason people keep bringing these scenarios up is due
| to the fact that electric cars are terrible for these
| cases. Nobody is suggesting they can't be used for daily
| commutes.
|
| Right now electric cars are for people who can afford to
| also own an ICE or rent an ICE for road trips (or who don't
| like road trips at all).
| hinkley wrote:
| Just look at the number of pickup trucks there are, with
| empty (even pristine) beds. Nobody is hauling stuff most
| of the time, but they got a vehicle that can.
| rootusrootus wrote:
| I think EVs make a great _second_ car. I drive a Tesla,
| my wife drives a Bolt, and we have an F250 for towing the
| travel trailer, hauling household stuff around, or going
| somewhere that charging infrastructure is going to be
| inadequate (haven 't really run into that yet, but the
| pickup is our catch-all). I can't see going back to ICE
| cars as daily drivers, but it'll be quite a while before
| we don't have at least one in our household. Especially
| as long as we continue to own the RV.
| carrolldunham wrote:
| so, to save the environment, everyone get two cars.
| rootusrootus wrote:
| I would use a lot more fossil fuel if I used the pickup
| as a daily driver. Getting an EV as a second car is the
| sensible choice.
| yholio wrote:
| Or, rather: a small enthusiast minority gets two cars,
| generates the critical mass required to build charging
| infrastructure etc., then everybody can switch directly
| to an electric when it becomes convenient for them.
| iso1210 wrote:
| It's an emotional decision, but even with that - well
| under 20% of vehicles sold in the US in 2019 are trucks
|
| https://www.goodcarbadcar.net/2019-us-vehicle-sales-
| figures-...
| cmrdporcupine wrote:
| Yep, well, this is why I drive a Volt and not a Tesla.
| The EV portion of it covers 90% of my use cases, and then
| I have the ICE to fall back on if I need it, which I do
| once in a while, mostly for ski or camping trips to
| places that will probably only ever get charging
| infrastructure in like... 20 yeras.
|
| Too bad GM killed it from their line-up.
| DarmokJalad1701 wrote:
| > that would take a Tesla a few hours
|
| Even with "version 2" superchargers, this is not true. With
| 250kW (v3) charging, you can get to a sufficiently high state
| of charge (>80%) in under 30 minutes. And the thing is, given
| how efficient an EV is, you _don 't need_ 2700 mega-joules
| (20 gallons of gas or 750 kWh) to go ~500 miles. The
| Cybertruck will do that range to with ~100-150 kWh of battery
| and charge up in under an hour. This will probably get faster
| over the coming year as charging rates go up.
|
| And like another comment pointed out, majority of charging
| happens overnight or during the day when the car sits idle. I
| own a Model 3 myself and I have not been to a supercharger in
| several months.
| bananabreakfast wrote:
| This is a point that needs to driven home.
|
| Yes, filling up gasoline delivers energy at an insanely
| high rate due to its density but the vast majority of that
| is wasted and not converted to miles driven.
|
| The real comparison is miles of range delivered per minute
| of fueling. And a Tesla supercharger is already competitive
| with gasoline by this metric. If hydrogen takes longer than
| gas to fill up a tank for a similar range then its already
| behind just charging directly.
| huntertwo wrote:
| 20 gallons of gas still only takes 5 minutes to fill. If I
| can get 125 KwH in 30 minutes with your v3 charging that's
| still a 6x multiplier, not really something you can ignore.
|
| Now you need bigger charging stations because people are
| spending longer at the pump or else you'll have longer
| lines. Adding to that, I sure as hell am not spending half
| an hour at a pump on an already long road trip.
|
| The lack of population density in the US, especially in the
| middle of the country, makes electric vehicles not a great
| choice for many people. I'm guessing this is why we see
| higher adoption in Europe on a consumer and infrastructure
| level.
| DarmokJalad1701 wrote:
| I live in Iowa. It's about as "middle-of-the-country" as
| it gets. Lines at charger stations are really a
| California problem as of now. I have never encountered it
| driving throughout the midwest and I have gone on some
| long road-trips.
|
| As for taking 30 minutes to charge, what people usually
| do is to make sure their charging stops line up with
| food/bathroom breaks. Realistically, if I drive 10-12
| hours in a day, I would stop about 3-4 times for
| food/bathroom breaks, if not more. This lines up
| perfectly with the range in my Model 3 AWD. In many
| cases, I have ended up having to get up and go get my car
| to avoid idle-rates because it finished charging while we
| were still eating.
|
| On these trips, I usually pick a hotel/B&B with
| destination charging so that I can get going in the
| morning the next day with a full battery.
| deeviant wrote:
| > 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.
|
| A 75% charge can happen in ~20 minutes on something like a
| 250kw Telsa super charger. Battery tech and battery charging
| tech will only get better/faster. Also the vast majority
| miles driven on the road aren't "road trip" miles in which
| you would see the drive-to-fuel/energy exhaustion over and
| over for days on end scenario. When a Tesla plugs in at home
| and charges over night, that's actually _more_ convenient
| than having to go to a gas station.
| TheRealPomax wrote:
| and economics. If I can make an H2 vehicle for less than it
| cost me to make a gas or electric vehicle, it's worth my time
| and money to push into or even create a market that'll buy
| them.
| aquadrop wrote:
| Using electricity usually is even more convenient, since you
| can do that at home, and very few of us have gas station in
| the garage.
| SomeoneFromCA wrote:
| If COVID will persist in future, oxygen byproduct could be very
| useful.
| hedora wrote:
| Any idea what the real world efficiency is? It sounds like it's
| limited to a narrow UV spectrum.
|
| I wonder if it's even vaguely competitive (in theory) with
| commercially available hydrogen crackers that use electricity
| from solar panels.
| timwaagh wrote:
| That's some very impressive news. Hope this will make hydrogen
| cheap.
| ehnto wrote:
| I am excited because hydrogen can be used in steelmaking for a
| much more carbon friendly process than burning coals. Cheap
| hydrogen will be a game changer for emissions regardless of if
| anyone uses it to power vehicles.
| timwaagh wrote:
| That's what my dad said. Personally i like the vehicles too.
| I think there will continue to be a sizeable market for
| petrol vehicles as long as bevs are difficult to charge.
| Hydrogen would be more easy to refill. Hydrogen could fill
| that market in time.
| jtriangle wrote:
| The real application here is power plants. Use hydrogen to
| heat water to turn a turbine to turn a genset to produce
| electricity, in the same way that we've been doing for ages
| now.
|
| The real question is, say you have a natural gas power plant
| that's been retooled (minimally) to run on hydrogen that they
| create on site. Now you're producing a ton of water vapor and
| tossing it into the air. If _all_ power plants run this way,
| that water vapor is going to be problematic as water vapor is
| an excellent greenhouse gas, so, if you 'd like to avoid
| that, you'll need to recondense the water and put it back
| into the cycle, which will harm efficiency if done in a 100%
| closed cycle.
|
| That's probably not a huge obstacle to overcome, because the
| water will likely have to be pure anyway in order to be
| usable, so, you could likely recapture waste heat and use it
| to distill water to a high purity and because your exhaust is
| likely full of higher purity water than you could otherwise
| get, it makes sense to recapture it.
|
| Additionally, you could solve in part, the main issue with
| renewables, which is energy storage, by converting excess
| capacity to hydrogen made by electrolysis that you can then
| burn in traditional power plants. Sure it's 70-80% efficient,
| and burning hydrogen is likely not going to beat ~62%
| efficient in a combined cycle plant (the current record for
| natural gas), it's much better to take that efficiency hit
| than it is to waste power, or further complicate the grid,
| and you'll get to keep ~40% of that energy based on my napkin
| math, which is better than 0% and you can put it anywhere,
| likely on the solar farm directly.
| pm90 wrote:
| Can't you just release the hot steam into a nearby
| river/large water body?
| poma88 wrote:
| I do not buy it, any random news about easy energy are just an
| appeal to lost hopes!
| justforfunhere wrote:
| From the original paper
|
| >> _SrTiO3 is a suitable photocatalytic material for the
| assessment of this possibility. This compound is a well
| characterized photocatalyst with a bandgap energy of 3.2 eV (ref.
| 11-14), and its EQE for overall water splitting has been improved
| by up to 69% over the past years using various refinements.
|
| Here, we increased the EQE to its upper limit by constructing
| highly active HER and OER cocatalysts on SrTiO3:Al particles
| site-selectively. This was accomplished by using a stepwise
| photodeposition method instead of an impregnation process, which
| results in random dispersion of the cocatalysts._
| janmo wrote:
| I am doubtful, but if true and if this can be deployed on a large
| scale hydrogen cars could be a viable alternative to battery
| powered EVs.
| _ph_ wrote:
| Unfortunately, splitting water into hydrogen and oxygen are
| only a part of the process. A lot of energy is wasted when the
| hydrogen has to be compressed for transport, storage and in the
| car. That makes hydrogen less attractive than batteries, even
| if we solve the inefficiencies of the hydrogen production.
|
| However, it would be great news for many other fields. One way
| to make hydrogen more storable is to produce methane. And of
| course use hydrogen directly for industrial applications, like
| steel production.
| JorgeGT wrote:
| It would be specially interesting for aviation, since the
| energy density of batteries is still too low for commercial
| aircraft. Airbus is pushing for zero emissions H2-powered
| planes: https://www.airbus.com/innovation/zero-
| emission/hydrogen/zer...
| jillesvangurp wrote:
| What makes hydrogen interesting in aviation is that it is
| possible to convert existing engine designs to burn
| hydrogen apparently. There have been a few tests with this
| recently.
|
| Mid term, hydrogen is the obvious way to clean up the
| aviation industry. Basically as soon as hydrogen prices
| drop below kerosene prices, companies will start doing this
| by themselves because it makes economical sense. Right now
| it's more of an investment for the long term. Airbus is
| clearly betting that this is going to happen in the next
| two decades or so. If you look at clean energy cost
| dropping over time, they might be right about that.
|
| Battery powered planes also make sense; just not for the
| bigger planes any time soon. But with another decade of
| battery improvements, GA planes & battery is going to be a
| no brainer-solution for a lot of use cases. Basically, this
| will be driven by cost. At some point battery powered is
| going to be cheap and good enough that the added advantage
| of low energy cost and vastly simpler/cheaper maintenance
| is going to be a killer argument. E.g. flight schools are
| already switching because it makes economical sense.
|
| If you look at the R&D pipelines of companies in this
| space, ten years could solve a lot of issues. Think
| double/triple the range of current electrical planes at
| half the cost. Small planes are expensive to operate
| currently and fuel & maintenance are big factors here.
| JorgeGT wrote:
| Completely correct, H2 either in fuel cells or burnt in
| turbines and battery-powered hybridization are two of the
| pillars of the EU's Clean Aviation R&D programme:
| https://clean-
| aviation.eu/files/Clean%20Aviation%20-%20Share...
| hef19898 wrote:
| For transportation, hydrogen can be absorbed by a carrier
| oil. That way it is basically inert, doesn't even count as
| dangerous goods for transportation purposes. No compression
| needed. In cars it is different, so.
| runeks wrote:
| What's the density of hydrogen using this method versus
| compression?
| hef19898 wrote:
| I'd have to look up the numbers. Cost wise, a pure
| hydrogen pipeline is cheaper for sure. At scale at least.
| Until that scale is reached, using carrier oil is much
| cheaper, but still competitive enough to get it going.
|
| EDIT: The oil is called marlotherm something, if memory
| serves well.
| tankenmate wrote:
| It is going to be very costly (energy and capital investment)
| to convert steel making to use hydrogen. A blast furnace is a
| well balanced chemical reaction where the coke serves two
| purposes; a source of carbon monoxide for turning ore in iron
| (Fe2O3(s) + 3 CO(g) => 2 Fe(s) + 3 CO2(g), very exothermic,
| good for turning the iron / steel into a liquid alloy), and a
| source of carbon for turning the iron into steel. All in one
| vessel and in one process no less. I guess you could do the
| first step using peroxide to strip the oxygen from the iron,
| but the second step in the same vessel at the same time?
|
| Fe2o3 + 3H2O2 => 2 Fe + 3 H2O, somewhat exothermic (if my
| rusty memory of enthalpy calculations are correct), not sure
| of the activation energy or need for catalysts).
|
| [EDIT] also forgot the peroxide reaction would probably
| require external heat to over come the latent energy required
| to turn the H2O into super heated steam so that you could
| melt the iron / steel. This would probably boil off a large
| chunk of the peroxide as well, so it might need to be done in
| a contained pressure vessel, which would probably affect the
| speed of the iron ore reduction.
| philipkglass wrote:
| _Fe2o3 + 3H2O2 = > 2 Fe + 3 H2O_
|
| This is not balanced correctly. There are 9 oxygen atoms on
| the left hand and only 3 oxygen atoms on the right hand.
|
| Hydrogen peroxide can act as a reducing agent relative to
| _some_ things, like permanganate anions, but it 's an
| oxidizing agent relative to metallic iron. Hydrogen
| peroxide cannot substitute for coal or hydrogen in steel
| production.
| hannob wrote:
| Look here: https://www.hybritdevelopment.com/
|
| Particularly the "Downloads" section, they have quite a bit
| of info reasonably easy to digest for interested lay
| people.
|
| It may be expensive, but it's pretty much the only game in
| town. The only possible alternative is direct electrolysis,
| but that's even less developed. The hydrogen path is from
| what I understand technically not that much different from
| direct reduced iron with natural gas, which is something
| that already is in use for a significant chunk of steel
| production.
| tankenmate wrote:
| Thanks, it's a good source. Also on the financial front
| of how they organised finance and created a route to
| market.
| ehnto wrote:
| The biggest steel mill in my state is switching to locally
| sourced green hydrogen. Written out, that sounds pretty
| funny. But it's produced with local solar energy farms, so
| it's pretty accurate.
|
| This is one area where carbon taxes are the obvious
| solution. Cost and availability is the biggest driving
| factor for industry. Furnace coal is available and cheap,
| but if you tax it heavily for it's emissions enough it
| won't be. Will steel become extinct? Of course not, the
| mills will switch to the next alternative, which is
| hydrogen. It will be ripe with opportunity, with solar
| farms and hydrogen plants popping up around steel mills.
|
| Already we are seeing coal plants written off as
| unprofitable and future mining projects are becoming less
| attractive to investors in an unpredictable future. Even
| without a carbon tax, we could see the cost of coal go up
| enough to make a local hydrogen industry make more sense.
| But we can speed the whole process up with smart carbon
| taxes.
| ClumsyPilot wrote:
| There is a steel mill that uses hydrogen, but it appears to
| be a recycling kind, rather than one that makes iron from
| ore with a blast furnace.
|
| https://www.rechargenews.com/transition/-world-first-as-
| hydr...
| tankenmate wrote:
| Yes, I suspect this is much easier as you don't need to
| alloy as the steel is already alloyed with carbon.
| _ph_ wrote:
| I am not a steel expert, but the steel industry is
| constantly talking about converting to hydrogen. Your sum
| formula has a bit lot of oxygen, shouldn't it be Fe2O3+3H2
| => 2 Fe + 2 H2O? In any case, they could use additional
| hydrogen for heating and burning it with ambient air.
| tankenmate wrote:
| I suggested using peroxide not hydrogen, as the peroxide
| reaction is more exothermic. Either way I suspect that
| you'd need to burn a lot of extra hydrogen to overcome
| the latent heat of water and create sufficient heat to
| melt the ore / alloy.
|
| A quick back of the envelope calculation would be at
| least 1 million litres of H2 per ton of steel. So maybe
| 2~3 million litres of H2 per manufactured car just for
| the steel alone?
|
| [EDIT] Peroxide also has the added benefit of being a
| liquid at room temperature.
| smegger001 wrote:
| I am reminded of the classic article "things I Won't Work
| With" by chemist Derek Lowe on the subject of Peroxides
|
| https://blogs.sciencemag.org/pipeline/archives/2014/10/10
| /th....
|
| they don't sound safe
| _ph_ wrote:
| Yes, peroxide being liquid certainly is nice, being a
| light gas is certainly one major obstacle in using H2.
| However I am surprised that the peroxide reaction would
| be more exothermic, as you would have to break the
| hydrogen from the peroxide first. 1 million litres of H2
| are just 90kg though, that isn't that much for a ton of
| steel.
| tankenmate wrote:
| It is only a bit more exothermic, about 20% more (again
| from my rusty enthalpy calculations). The downside of
| course is making the peroxide in the first place.
|
| Also, peroxide is relatively safe (compared to gaseous
| hydrogen) to handle up to ~150C.
| jillesvangurp wrote:
| The "Just have a think" youtube channel did a nice episode
| on this topic last week:
| https://www.youtube.com/watch?v=ywHJt88H5YQ
|
| Apparently there are several viable ways to make clean
| energy work in this space. And there are some companies
| starting to do some of this already. Carbon prices is short
| term going to be needed to cover the price difference.
|
| But the cool thing is that it boils down to cost per MWH of
| energy per tonne of steel. As that goes down, it becomes
| more viable and eventually cheaper.
| stewbrew wrote:
| When there is wind or sun, it's not entirely impossible to
| produce hydrogen on site - within limits of course. Then the
| question is what kind of energy storage is more cost
| efficient on the long run.
| ummwhat wrote:
| If there is sun why not skip the middle man and use an
| array of mirrors for direct heating?
| stewbrew wrote:
| Oh come on. Anyway, the sun doesn't shine at night. In
| the winter, the situation is difficult too. You need
| storage but you don't necessarily have to move the
| storage across countries.
| AnHonestComment wrote:
| It also needs to beat growing corn and burning it as
| alcohol on total process efficiency.
|
| We can be carbon neutral by using plant based fuels, so
| anything exotic needs to perform better than burning
| plant/algae alcohol or gas.
| thysultan wrote:
| The idea is to use water as the fuel and convert to hydrogen
| just in time for combustion.
| bawolff wrote:
| How would that work? That sounds like a perpetual motion
| machine.
| sputr wrote:
| No, it's not :)
|
| Where would you get the energy to split the water? Why not
| just use that energy directly :).
|
| The idea is to use the water as an energy carrier. You
| split the water into H2, than use that to power a car
| producing water as the only output.
| rzzzt wrote:
| If cars produce water as exhaust, will there be constant
| rain showers on congested roads?
| maxerickson wrote:
| They already produce plenty of water in the exhaust.
| _ph_ wrote:
| Right, I did a simple calculation, for the same distance
| driven, both gasonine and fuel cell cars produce pretty
| much the same amount of water, about 100ml/km. Only
| difference is, with gasoline that water is mostly vapour,
| so it doesn't get on the road so much, fuel cell cars
| have small tanks not to wet the road constantly.
| ianai wrote:
| Watch a YouTube of a hydrogen car review. They produce
| maybe a cup of water for a consider amount of driving.
| It'd evaporate relatively quickly.
| hannob wrote:
| I find it amazing (in a bad way) that whenever you talk about
| hydrogen someone comes up and wants to talk about cars.
|
| There's a number of use cases where clean hydrogen will be
| desperately needed. This starts with areas where hydrogen is
| already used today - but it's hydrogen made from fossil fuels -
| like ammonia production and includes areas like steel
| production where hydrogen really is the only game in town for a
| low-carbon production.
|
| We'll need all the clean hydrogen we can get, and probably more
| than that. There's no plausible scenario where we'll have
| excess hydrogen that we can waste in an area where it's just
| vastly less efficient than the available alternative.
| marcosdumay wrote:
| On the specific case of steel production, it's way more
| likely that people will settle on synthetic carbon based
| fuels.
|
| Of course, producing those uses hydrogen too, so no big
| change.
| paledot wrote:
| Yeah, I really don't see a case where large amounts of
| hydrogen are being transported commercially. Anything you
| don't need on site makes much more sense to convert to
| synfuel.
| hannob wrote:
| Why would that make any sense?
|
| (Synfuels are really, really inefficient, you basically
| only want them in places where you need the high energy
| density and can't avoid them, like aviation.)
| marcosdumay wrote:
| Because the carbon has an important role on the chemistry
| of making steel.
| Triv888 wrote:
| > I find it amazing (in a bad way) that whenever you talk
| about hydrogen someone comes up and wants to talk about cars.
|
| It would solve the battery charging problem that electric
| cars have (for long trips) while not polluting like
| conventional cars.
| BartBoch wrote:
| Any solution that is applied to massively produced product (a
| car) will get massive funding, research grants and it will
| only improve over time. This way it can be distributed to
| other areas quicker and at lower cost. So yes, implementing
| hydrogen in cars is a massive success to other industries.
| akrymski wrote:
| I'm long hydrogen vehicles due to the convenience factor.
| Convenience trumps efficiency.
|
| EVs are great if you own a house with a driveway and get to
| charge overnight. Outside of USA, how common is that really? Most
| people live in apartments in cities, where a parking spot is hard
| to find.
| smt88 wrote:
| > _EVs are great if you own a house with a driveway and get to
| charge overnight._
|
| I think denser cities will eventually have battery-swapping
| stations, where you just get a new battery whenever you're
| running low. They then fast-charge your depleted battery and
| give it to a new customer later.
|
| The big obstacles are compatibility and preventing people from
| abusing the system to get batteries in better condition for
| free, but I think countries with more central planning (like
| China) could force those issues.
| pm90 wrote:
| You could also use regulations to standardize battery design
| and performance criteria right here in the US. Just like we
| have regulations that dictate what can and can't be
| "gasoline". Make batteries a commodity.
| pm90 wrote:
| Garages are also not very common in non US countries. As the
| population urbanized further into denser cities this will make
| this problem even more acute. We absolutely need a better
| solution.
| joshuaheard wrote:
| You also have the problem of range with an EV, which can only
| go a few hundred miles. You would need to swap out the
| batteries to have an instant charge. With hydrogen, you could
| have ubiquitous automated solar powered gas stations.
| koolk3ychain wrote:
| Improvements like this I believe, show how much science Elon Musk
| doesn't understand or is willing to acknowledge. Sure, I'm a fan
| of the Musk, however advancements like this show his hydrogen FUD
| is really just a marketing ploy / positioning stunt [1].
|
| Once we can create better means than metal hydride [1] in order
| to store hydrogen it _will_ become the de-facto fuel for long
| haul trucks and electric aircraft. Assuming fuel-cell tech
| continues it 's steady YoY improvement, hydrogen IS the future.
|
| 0 - https://www.cnbc.com/2019/02/21/musk-calls-hydrogen-fuel-
| cel...
|
| 1 - https://www.energy.gov/eere/fuelcells/metal-hydride-
| storage-...
|
| edit - of course, I should've known the Tesla shills would
| downvote this... You dirty animals, I own a Model 3.
| wh0knows wrote:
| While hydrogen might end up "being the future" this prediction
| has as much substance (perhaps less as there is no scaled up
| application of the technology) as Musk's claim.
|
| Just want to make the point that the idea of hydrogen still
| having a lot of potential and is worth investigating is a
| better claim than making a somewhat baseless assertion that
| hydrogen is the certain way forward over batteries.
| [deleted]
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