[HN Gopher] Earth's subsurface may hold up to 5.6 x 106 million ...
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Earth's subsurface may hold up to 5.6 x 106 million metric tons of
hydrogen
Author : wglb
Score : 50 points
Date : 2024-12-23 14:51 UTC (2 days ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| pfdietz wrote:
| If extracted and fully oxidized, the water would raise ocean
| levels maybe 4 cm.
|
| The Earth also includes vast quantities of reduced metals like
| iron, more than enough to react with all the oxygen in the
| atmosphere. Perhaps some way could be found to exploit that, at
| least a little bit.
| foundart wrote:
| Well there's an idea for a sci-fi disaster book:
| "Rustpocalypse" (if too much of that iron were to be oxidized.)
| suprfsat wrote:
| Rust Evangelion Strike Force
| FredPret wrote:
| Apocalypse (written in Rust)
| seangrogg wrote:
| *rewritten in Rust
| pfdietz wrote:
| All it would take would be for photosynthesis to be
| terminated, and then wait a few million years for erosion and
| volcanism to expose enough reduced material to soak up the
| atmosphere's oxygen.
|
| What's weird is that, as far as I know, there's no feedback
| mechanism that's been identified that keeps the atmosphere's
| O2 level stable. It may have been stable since the Cambrian
| just because if it hadn't been, we wouldn't have evolved, an
| anthropic argument.
| Earw0rm wrote:
| Fire must surely have a role to play there? Too much O2 and
| plants burn easily, too little and fires won't take hold.
|
| And we don't know AFAIK that it's been entirely stable.
| There's some debate over what the level was in the
| Cretaceous for example.
| pfdietz wrote:
| If anything, fire would be a positive feedback. That's
| because fire produces charcoal, and charcoal doesn't
| decompose. Instead, it gets washed into the ocean and
| eventually buried. It's not photosynthesis itself that
| causes O2 accumulation in the atmosphere, it's the burial
| and sequestration of reduced material from
| photosynthesis.
| ryao wrote:
| If the metal is reduced, then it should not be reactive. How
| does this become relevant to all of the oxygen in the
| atmosphere?
| pfdietz wrote:
| What? Carbon is reduced. Hydrogen is reduced. Any fossil fuel
| is reduced. All can give up electrons to oxygen and so be
| oxidized, liberating energy.
| ryao wrote:
| I went with what you wrote since it has been a while since
| I took general chemistry, but upon doing a simple lookup, I
| found that your terminology is wrong. In redox reactions,
| the oxidizing agent is reduced while the reducing agent is
| oxidized:
|
| https://en.wikipedia.org/wiki/Redox
|
| Here, the metal is the reducing agent. If it were somehow
| reduced in redox reactions, there not much chance of it
| being oxidized as that would make the metal an oxidizing
| agent that wants electrons, not a reducing agent that gives
| electrons.
|
| That said, these things have already been oxidized (not
| reduced) and thus there is no chance to have them consume
| oxygen. You need the pre-oxidized material in order to be
| able to consume oxygen.
|
| Finally, you failed to answer my question regarding the
| relevance of these metals to atmospheric oxygen. They
| should be inert having been oxidized long ago. That is why
| rocks are full of oxides, such as silicon dioxide and
| aluminum oxide, despite being composed of metal.
| pfdietz wrote:
| I think there's confusion here between "is reduced"
| meaning "has been reduced" vs. "and is then reduced".
|
| Iron in the Earth is mostly in a reduced state (either
| Fe(+2) or even elemental iron). Upon exposure to the
| atmosphere it is oxidized to Fe(+3), changing from a more
| reduced to a more oxidized state (and similarly for other
| things in reduced states, such as manganese and sulfur
| and organics).
| ryao wrote:
| Plenty of iron in the earth is in the form of iron oxide,
| which is already oxidized and won't oxidize further upon
| exposure to the atmosphere.
| tolciho wrote:
| Banded Iron Formation: the reunion tour.
| blindriver wrote:
| If the hydrogen gas escaped and left the atmosphere, would it
| affect the orbit around the sun, possibly causing the Earth to
| cool too much?
| tzs wrote:
| I'd expect not, for 2 reasons.
|
| * I can't think offhand of any mechanism by which it would
| escape in some preferred direction. I'd expect to be pretty
| much evenly spread in all directions, so any effects on the
| orbit of what remains caused by the hydrogen leaving in any
| particular direction would be cancelled out by the effects of
| hydrogen leaving in the opposite direction.
|
| * We are talking about 5.6 x 10^12 tons of hydrogen. The mass
| of the Earth is 5.972 x 10^21 tons. The mass of the hydrogen is
| about 1 billionth the mass of Earth. That's about the ratio of
| the mass of a grain of rice to the mass of the International
| Space Station.
|
| Tossing that small of mass away, even if it was all in one
| direction, is not going to do anything significant to your
| orbit unless you tossed it away with very very very high
| velocity. A naive calculation just using Newtonian mechanics
| suggests it would have to be much faster than the speed of
| light to carry enough momentum away to matter. I'll leave it to
| others to figure out what fraction of the speed of light it
| would have to be going to have equivalent momentum.
| Someone wrote:
| > I can't think offhand of any mechanism by which it would
| escape in some preferred direction.
|
| I think the sun's heat would give it a slight preference to
| escape from the sunny side of earth.
| hollerith wrote:
| No because the escaping gas would on average have the same
| velocity as the (lighter) Earth does.
| ngcc_hk wrote:
| If two mass separated, it will affect their velocity.
|
| But does this hydrogen escapee like a rocket gas. Or it is just
| a restructure or a bit move of CoG.
|
| One also note if it not too fast escape as earth rotate the
| overall effect depend upon the uniformity of the "escape" as
| the net effect can be zero or more depends upon its location on
| earth. Mostly as it is not align with the tangent of travel, it
| will affect.
|
| How much as point out relates also the mass. But even the minor
| variations make the polar star changes. It will have affect.
| karaterobot wrote:
| This is one of those comments where I'm not sure what the
| downvotes meant. Do people think a downvote signifies a 'no'
| answer to a yes/no question, or are they trying to say "I don't
| appreciate it when people ask questions"?
| reshlo wrote:
| In this case it's probably "this is a silly question".
| karaterobot wrote:
| Maybe it is, but the person asking it will never know that
| unless someone takes the time to respond saying so.
| lazide wrote:
| There is zero chance free hydrogen would exist long enough in
| our atmosphere for it to escape. It would convert to water long
| before hand.
| reshlo wrote:
| > Hydrogen escape on Earth occurs at ~500 km altitude at the
| exobase (the lower border of the exosphere) where gases are
| collisionless. Hydrogen atoms at the exobase exceeding the
| escape velocity escape to space without colliding into
| another gas particle.
|
| > For a hydrogen atom to escape from the exobase, it must
| first travel upward through the atmosphere from the
| troposphere. Near ground level, hydrogen in the form of H2O,
| H2, and CH4 travels upward in the homosphere through
| turbulent mixing, which dominates up to the homopause. At
| about 17 km altitude, the cold tropopause (known as the "cold
| trap") freezes out most of the H2O vapor that travels through
| it, preventing the upward mixing of some hydrogen. In the
| upper homosphere, hydrogen bearing molecules are split by
| ultraviolet photons leaving only H and H2 behind. The H and
| H2 diffuse upward through the heterosphere to the exobase
| where they escape the atmosphere by Jeans thermal escape
| and/or a number of suprathermal mechanisms.
|
| https://en.wikipedia.org/wiki/Diffusion-limited_escape
| lazide wrote:
| I can't decide if it is a good point, or an irrelevant
| point! Hah.
|
| No free/unbound hydrogen from the surface is going to
| escape directly that way. It will bind with oxygen or the
| like long beforehand and become water.
|
| But yes, a small portion of those molecules may later be
| broken down and may escape the planet that way. But
| statistically, very few of them are likely to do so.
|
| So, maybe technically correct?
| sebastianmestre wrote:
| The figure in the title expressed in normal units
|
| 5.6 * 10^15 kilograms
| WorkerBee28474 wrote:
| I think you meant to say 1.1 trillion elephants
| acchow wrote:
| 2.24 billion olympic sized swimming pools
| adonovan wrote:
| Thanks, I didn't notice the second million and wondered why a
| day's supply of energy would be scientific news.
| peeters wrote:
| They wasted an opportunity to get a third thing meaning
| "million" into the same number with 5.6 x 10^6 million
| megagrams.
| ars wrote:
| There is around 1 trillion tons of oxygen in the atmosphere, if
| you burned all the hydrogen you would deplete all of the oxygen
| on earth.
|
| Let's not.
|
| Although realistically we only need a tiny fraction of the
| hydrogen.
| stouset wrote:
| On the plus side if we use up all the oxygen, we'll have solved
| the problem of burning fossil fuels producing CO2!
| shiroiushi wrote:
| If we use up all the oxygen, we'll have solved _every_ social
| or political problem that currently plagues humanity. I think
| it 's a good strategy.
| dmichulke wrote:
| FWIW, I consider extinction avoidance also a political
| problem
| hgomersall wrote:
| Closer to 10^15 tonnes, so a few orders of magnitude out.
| shwouchk wrote:
| If siblings are to be believed, there is nothing we can do
| about it aside from being very careful not to release the
| hydrogen into the atmosphere (at which point it will "burn"
| whether we want to or not)
| m3047 wrote:
| Purple Earth hypothesis. The first (AFAWK) photosynthetic
| critters were cyanobacteria. They produced enough oxygen to
| kill off everything which couldn't withstand its reductive
| effects. Oxygen levels have been much higher than they are
| today, presumably this is what made e.g. 6 foot centipedes a
| possibility.
| fulafel wrote:
| This article the crux, is this about extractable hydrogen or some
| proxy about it (vs just "interesting number"), to the last
| sentence.
|
| The abstract is again the best summary:
|
| "[...] Given the associated uncertainty, stochastic model results
| predict a wide range of values for the potential in-place
| hydrogen resource [103 to 1010 million metric tons (Mt)] with the
| most probable value of ~5.6 x 106 Mt. Although most of this
| hydrogen is likely to be impractical to recover, a small fraction
| (e.g., 1 x 105 Mt) would supply the projected hydrogen needed to
| reach net-zero carbon emissions for ~200 years."
| Animats wrote:
| The Albanian mine: _" The researchers found that the gas bubbling
| from the pool was more than 80 per cent hydrogen, with methane
| and a small amount of nitrogen mixed in. It was flowing at a rate
| of 11 tonnes per year, almost an order of magnitude greater than
| any other flows of hydrogen gas measured from single-point
| sources elsewhere on Earth's surface. To determine the source of
| the gas, the researchers also modelled different geological
| scenarios that could produce such a flow. They found the most
| likely scenario was that the gas was coming from a deeper
| reservoir of hydrogen accumulated in a fault beneath the mine.
| Based on the geometry of the fault, they estimate this reservoir
| contains at least 5000 to 50,000 tonnes of hydrogen. "It's one of
| the largest volumes of natural hydrogen that has ever been
| measured," says Eric Gaucher, an independent geochemist focused
| on natural hydrogen. But it still isn't a huge amount, says
| Geoffrey Ellis at the US Geological Survey."_
|
| This is the second or third time someone found modest amounts of
| hydrogen underground, and then started making claims of vast
| quantities being available. There's been so much well-drilling
| worldwide for other materials that if hydrogen was anywhere near
| the surface, it would have been found by now. The "gold hydrogen"
| enthusiasts claim well depths of a few kilometers are enough. Oil
| and natural gas wells routinely go that deep.
|
| So far, nobody has a "natural hydrogen" well producing. Even
| though this startup [1] said they would have one by the end of
| 2024. Their "news" releases are all about going to meetings,
| making deals, and such. Not much mention of drilling, unlike the
| statements they made a few years ago.
|
| There's one well in Mali which yields enough hydrogen to run an
| auto engine driving a generator. That's it for actual output.
| That deposit been known since the late 1980s, and invested in
| since 2012. Exploratory wells were drilled in 2018. Results from
| that are, somehow, hazy.[2] Not finding followups since 2018.
|
| The hype is strong here.[3]
|
| [1] https://helios-aragon.com/news/
|
| [2]
| https://www.sciencedirect.com/science/article/abs/pii/S03603...
|
| [3]
| https://www.scopus.com/record/display.uri?eid=2-s2.0-8518695...
| roenxi wrote:
| > There's been so much well-drilling worldwide for other
| materials that if hydrogen was anywhere near the surface, it
| would have been found by now.
|
| I'd believe it because geologists are thorough. I'd also not be
| that shocked if nobody was testing for hydrogen because it is a
| gas. I'd imagine it is possible to drill through a hydrogen
| deposit and not even notice it is there. Are we _sure_ that the
| prospectors were checking for hydrogen? All over the globe?
|
| I suppose if they found a real lode of the stuff it might
| accidentally blow up the drilling crew. That'd make headlines.
| defrost wrote:
| > Are we sure that the prospectors were checking for
| hydrogen? All over the globe?
|
| Yep .. checking for _everything_ really - the costs for
| drilling bore samples are high enough that it 's commonplace
| to log bores to have the data to store or onsell even if
| specific targets aren't found.
|
| The major explorers have petabytes of surface chemisty,
| seismic, EM, borehole samples and logs, radiometrics,
| magnetics, gravity, etc. in primary archives scattered across
| the globe and routinely digitised and merged into private
| reserve estimations.
|
| There are _many_ drill hole logging and interp software
| packages kicking about, eg: https://www.csiro.au/en/work-
| with-us/industries/mining-resou...
| roenxi wrote:
| Yeah I've sat on an exploration drill rig and I have a
| vague grasp of the physics and chemistry. That is why I'm a
| little sceptical - what exactly would the process be for
| identifying a hydrogen resource?
|
| We're dealing with a light gas that would probably escape
| from core samples very quickly; especially under normal
| conditions. They'd need to get an accurate read during core
| drilling or be able to identify specific a non-magnetic gas
| with density of 0 underground which sounds pretty
| challenging - especially since it seems to have no special
| commercial interest for most of history. Is there a
| standard that you have to have a gas monitor attached to
| the drill hole? I don't remember anyone pointing one out to
| me or complaining that theirs was broken but stranger
| things have happened. Can hydrogen even be detected with
| magnets or surface chemistry analysis?
|
| The way sound waves bounce around underground makes it
| quite challenging to pick things up. The geologists have
| put a lot of effort into this exact problem but prospecting
| for _hydrogen_ sounds damn difficult and I 'd be surprised
| if we had global coverage for it.
| defrost wrote:
| In the drill core, even after gas escapes, there'd be
| specific types of capping material that can trap hydrogen
| under pressure, below that there'd be a reduced density
| of more porous material.
|
| Hydrogen _prospectors_ looking backwards at drill core
| logs would be looking for signature transitions and
| retesting fields, looking again at the seismic results to
| find ROI 's in historic results.
|
| Hence:
|
| Geological signatures:
| https://academic.oup.com/jge/article/21/4/1242/7676857
|
| Same authors, restricted access (for now): Geologic
| hydrogen: An emerging role of mining geophysics in new
| energy exploration -
| https://library.seg.org/doi/10.1190/image2024-4100417.1
|
| Old people rambling: Des FitzGerald on
| geophysical exploration for naturally occurring hydrogen.
| Des outlines the current state of exploration for natural
| hydrogen and discusses geological mechanisms for hydrogen
| generation.
|
| ~ https://www.tandfonline.com/doi/full/10.1080/14432471.2
| 024.2...
|
| etc.
| roenxi wrote:
| If they have to theorycraft a resource based on traces of
| where the hydrogen used to be, but no longer is then it
| is entirely possible that big hydrogen deposits have just
| been missed. That seems to be literally what the article
| today is about. For 90% of minerals they can just say
| what is in the drill sample is what is underground,
| exploration geologists aren't generally in the business
| of imagining what might have been in the core
| independently of what was directly measured.
|
| If we need to apply specific theories to the exploration
| samples then the "There's been so much well-drilling
| worldwide for other materials that if hydrogen was
| anywhere near the surface, it would have been found by
| now" logic doesn't hold. Since the evidence has to be
| interpreted before we can know if there is a deposit it
| is quite possible that it was interpreted wrongly on a
| mass scale. You're linking to papers suggesting
| innovative novel methods for finding the stuff or talking
| about rechecking based on the latest theoretical
| understanding, suggesting we don't actually have a big
| historic archive to draw on.
|
| I'm not saying geologists are ignorant, just that
| Animats' logic doesn't hold for hydrogen. There could be
| massive deposits that we technically already have the
| data for except nobody ever bothered to look for it.
| lazide wrote:
| Uh, if the gas had any useful quantity at all it would be
| under pressure and would be coming out of the borehole
| with noticeable speed/pressure.
|
| Most natural gas is also hydrogen. This isn't that
| unusual, in actuality.
|
| What is unusual is 'pure' hydrogen, as most processes end
| up combining it into a denser composite molecule. Like
| water, or methane, etc.
| ianburrell wrote:
| Natural gas is methane. Methane is composed of hydrogen,
| but it is mostly carbon by weight. Chemicals are
| different than their components. Water is also made of
| hydrogen but it takes work to split it.
| lazide wrote:
| Natural gas depending on source can have a couple percent
| free hydrogen. Adding more is apparently becoming more
| popular.
|
| In some markets, it comes from LNG which is pretty pure
| methane, in others it comes from wells which has more
| hydrogen as well as other contaminants like sulfides.
| Animats wrote:
| Right, most analyses of cores might not find small traces
| of hydrogen. But if someone looking for natural gas
| drilled into a sizable hydrogen deposit, it would be hard
| not to notice that the methane had way too much hydrogen.
| scott7ree wrote:
| As a prospector myself, this is false. Assays are expensive
| for traditional minerals and we never assay for hydrogen as
| that requires a totally different set of procedures.
| onlyrealcuzzo wrote:
| How often are people drilling for gold or something and
| accidentally stumble upon oil?
|
| I can't imagine this is a common occurrence, given how much
| effort people put into oil exploration...
| scott7ree wrote:
| Often an explorer looking for gold finds something else
| like copper or nickel. Oil however is generally found in a
| different environment. H2 is created through
| serpentinization in areas more prone to mineral discovery.
| scott7ree wrote:
| Correct, testing for a gas is a lot different than
| traditional soil and rock sampling and assays techniques.
| throwaway519 wrote:
| We don't discover gold or diamond mines when drilling for oil
| but that's not to suggest we don't believe they don't exist.
|
| The number of holes made to get oil out is quite small in
| comparison to the surface area of the globe.
| defrost wrote:
| The number of holes made to probe the dimensions of oil and
| gas fields greatly exceeds the number of holes made to get
| oil out .. and the number of holes drilled to estimate
| mineral reserves (copper, gold, kimberlite (diamonds),
| bauxite, etc. etc. etc) is large in comparision to oil wells.
|
| The point of all those holes is to log layers, horizons,
| sediments, etc and to map out the geology of very large areas
| .. much much much larger than the combined bore hole diameter
| areas.
|
| Of course boreholes are the final step in "proofing" siesmic
| results that map out many layers across large areas and allow
| geologists to rule out many areas as not having the
| structures required to trap gases.
| Hilift wrote:
| Global production of hydrogen is about 75 million tons, about
| half from ammonia, half from capture during petroleum products
| (refining). That's a problem primarily due to it is plateaued
| and there isn't capability to increase supply unless someone
| makes ammonia crackers more efficient. The other major obstacle
| is natural gas has been artificially inexpensive due to the
| abundance of supply due to fracking. It's hard to compete with
| it. It's possible to build turbines that burn ammonia, but no-
| one wants it.
|
| https://www.iea.org/data-and-statistics/charts/global-demand...
|
| https://www.irena.org/Energy-Transition/Technology/Hydrogen
|
| https://www.crystec.com/kllhyame.htm
| ianburrell wrote:
| Hydrogen is used to produce ammonia, not the other way
| around. There is no natural source of ammonia. The first link
| is all about the use of hydrogen. The third is about ammonia
| cracker which may be useful to transport ammonia and turn
| back into hydrogen.
|
| Most hydrogen is produced by steam reforming methane, called
| gray hydrogen.
| oefrha wrote:
| > stochastic model results predict a wide range of values for the
| potential in-place hydrogen resource [10^3 to 10^10 million
| metric tons (Mt)] with the most probable value of ~5.6 x 10^6 Mt.
|
| As a former physicist, I find it hard to take anyone who dares to
| give two significant figures on such a terrible estimate
| seriously. At the very least tells me they don't know shit about
| statistics. And whoever is clueless enough to repeat the figure
| in such a misleading title should be banned from scientific
| publishing.
| phtrivier wrote:
| When I started doing math seriously, I also feel strongly in love
| with "existence proof", where you were asked to prove that
| "something" existed, and any logical reasoning was considered
| fair game, even if you never found the "something".
|
| Then, I started doing applied maths, where proving the existence
| of a solution is a nice bonus, but finding an approximate
| solution is the goal.
|
| Here, we have an example of a funny proof of existence that does
| not tell you where to drill.
|
| Some carbon was emitted during the publishing of this model -
| that will be so much more carbon to offset if we ever end up
| actually finding some real hydrogen.
| h_tbob wrote:
| CO2 has its problems but at least nature automatically recycles
| it and produces O2 again.
|
| But what about hydrogen? Wouldn't burning it consume our oxygen
| supply with no way to replenish without large scale electrolysis?
| Seems like this could be a worse disaster since nature doesn't do
| that by default.
| dvh wrote:
| It's only 0.000001 of the mass of Earth's atmosphere (assuming
| 5e18kg)
| philipkglass wrote:
| No, photosynthesis turns water into oxygen and hydrogen-
| containing organic compounds.
|
| https://en.wikipedia.org/wiki/Photosynthesis#Refinements
|
| _Samuel Ruben and Martin Kamen used radioactive isotopes to
| determine that the oxygen liberated in photosynthesis came from
| the water._
| johnea wrote:
| Alright! More stuff to set on fire!!!
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