[HN Gopher] Hydrogen: Does Earth hold vast stores of a renewable...
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Hydrogen: Does Earth hold vast stores of a renewable, carbon-free
fuel?
Author : onychomys
Score : 29 points
Date : 2023-02-16 21:43 UTC (1 hours ago)
(HTM) web link (www.science.org)
(TXT) w3m dump (www.science.org)
| nonethewiser wrote:
| Yeah, in natural gas deposits
| diggernet wrote:
| Surprisingly, they are talking about actual hydrogen deposits,
| in one case 98% pure.
| [deleted]
| asimpletune wrote:
| Natural gas is made of carbon, no?
| gerad wrote:
| Carbon and hydrogen. CH4 - I believe it's true that most
| hydrogen today comes out of natural gas deposits [1]. Also
| helium for that matter [2].
|
| [1]: https://www.energy.gov/eere/fuelcells/hydrogen-
| production-na...
|
| [2]: https://geology.com/articles/helium/
| Rimintil wrote:
| I think this is important to note about hydrogen as a 'clean'
| fuel source:
|
| > Today's hydrogen is "gray," made by reacting methane with steam
| at high pressures or using fossil fuels in other ways. Those
| processes emit some 900 million tons of carbon dioxide every
| year, almost as much as global aviation. In principle, that
| carbon could be captured and sequestered underground, yielding
| "blue" hydrogen. But most hopes rest on "green" hydrogen--using
| renewable solar or wind power to split water molecules into
| oxygen and hydrogen with electrolyzers.
|
| _Today_, it is not a clean source of energy for vehicles.
| notorandit wrote:
| Carbon free is not renewable, isn't it?
|
| Wasn't the plan for renewables?
| barathr wrote:
| I was hoping to see in the article -- but didn't -- an analysis
| of the CO2e per KJ produced from natural hydrogen. Water vapor is
| a greenhouse gas and it'd be important to do the math to see how
| much better it is vs. other alternative fuels. (I expect it to be
| better, but how much is the question.)
| DennisP wrote:
| Water vapor is a greenhouse gas but it's not a driver of global
| warming, because of rain. Total water vapor is a function of
| global temperature, not the other way around. Put extra water
| vapor in the air, and it will just rain out.
| jojobas wrote:
| You don't have to release it as vapor. Otherwise energy is
| energy and depositing it into the atmosphere raises the
| equilibrium liquid/vapor point.
| sp332 wrote:
| Putting water into the air at low altitudes doesn't do much for
| global warming. The best way to reduce the effects of water
| vapor at high altitudes is... to reduce warming.
| https://en.wikipedia.org/wiki/Greenhouse_gas#Role_of_water_v...
| onychomys wrote:
| The HN bot took "Hidden" off the front of this headline, which in
| this case is probably not the right call on its part. The hidden
| part is important!
| pvg wrote:
| You can usually edit the title to fix this, otherwise send an
| email to the contact address at the bottom of the page.
| [deleted]
| hydrobore wrote:
| I thought it was a really captivating and well written article.
| News on hydrogen often seems to swing between too expensive to
| produce and its the future. Out of the blue, news in the UK this
| week says hydrogen will be added to the natural gas supply from
| 2025.
| panick21_ wrote:
| Why this is interesting, we already have such a fuel, we found it
| 80 years ago and its called Thorium. And Uranium isn't bad
| either.
|
| And we don't have to find it, every rare earth mine thorws out
| absurd amounts of it. We have to much of it without even trying.
|
| We just to dumb and lazy to anything with it.
| starbase wrote:
| In what sense is fossil hydrogen renewable?
| diggernet wrote:
| "Critically, natural hydrogen may be not only clean, but also
| renewable. It takes millions of years for buried and compressed
| organic deposits to turn into oil and gas. By contrast, natural
| hydrogen is always being made afresh, when underground water
| reacts with iron minerals at elevated temperatures and
| pressures. In the decade since boreholes began to tap hydrogen
| in Mali, flows have not diminished, says Prinzhofer, who has
| consulted on the project. "Hydrogen appears, almost everywhere,
| as a renewable source of energy, not a fossil one," he says. "
| Arrath wrote:
| Good question...uh.. a geological timeframe?
| greenthrow wrote:
| This is a very poor quality article. Mining the earth for fuel
| when wind and solar are already the cheapest form of power is
| really stupid.
| bloppe wrote:
| Is hydrogen really more renewable though? It releases energy when
| combined with Oxygen to make water, and it requires energy to
| split it from water (electrolysis). In this sense, it's not
| fundamentally different from fuel, which releases energy and
| carbon when burned, but requires energy (sunlight) and carbon
| (CO2) to re-create via photosynthesis. The involvement of carbon
| is a difference, but either way it's a 2-way street; we can't use
| either of them forever without reversing the process at some
| point.
| mytailorisrich wrote:
| The story is about natural hydrogen produced through water-rock
| reactions.
|
| This means it can be extracted 'for free' like natural gas and
| is naturally continually renewed.
| sp332 wrote:
| _The main engine of natural hydrogen production is now thought
| to be a set of high-temperature reactions between water and
| iron-rich minerals such as olivine, which dominate Earth's
| mantle. One common reaction is called serpentinization, because
| it converts olivine into another kind of mineral called
| serpentinite. In the process, the iron oxidizes, grabbing
| oxygen atoms from water molecules and releasing hydrogen._
|
| So we might run out of olivine at some point, but it's going to
| be a long time.
| Teknoman117 wrote:
| I imagine so. The main trouble with the biofuels is that you'd
| have to get everything else right for it to truly be neutral
| impact. (i.e. not depleting the soil, making the chemical
| fertilizer, reactions to convert biomass into ethanol, etc.)
|
| Electrolyzing water with wind/solar/nuclear would seem to
| result in far fewer steps that could go wrong.
| diggernet wrote:
| The article talks about how they believe natural processes are
| constantly refilling the reservoirs. So in this context
| renewable means potentially not a limited source.
| MithrilTuxedo wrote:
| If it does, releasing it would cause the exact same problems
| releasing fossil fuels has caused.
| sp332 wrote:
| There is one fewer problem, which is that burning hydrogen for
| fuel doesn't cause global warming.
| jakzurr wrote:
| So maybe there's a lot, maybe there's not. One quote from the
| article, though, is so typical:
|
| "We have the concept, we have the tools, the geology. ... We only
| need people able to invest."
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(page generated 2023-02-16 23:00 UTC)