Sub-zero water splitting marks a new dawn for solar hydrogen production(chemistryworld.com)
chemistryworld.com
Sub-zero water splitting marks a new dawn for solar hydrogen production
https://www.chemistryworld.com/news/sub-zero-water-splitting-marks-a-new-dawn-for-solar-hydrogen-production/4013887.article
9 comments
This is explicitly aimed at producing energy in cold environments (high altitude, polar regions), so it's less of an issue (and not exactly the point). Anyway, they seem to aim at 12% STH efficiency and provide some examples (assuming 65% hydrogen fuel cell efficiency):
Then, powering a Raspberry Pi computing device (PRPi = 4W) for an autonomous measurement device year-round at the > Neumayer III station (70.68°S, 8.27°W, Tavg,y = −15.5 °C) would prospectively require a module area of 0.41 m2, whereas at Paranal observatory (Chile, 24.63°S, 70.40°W, Tavg,y = 0.4 °C) 0.18 m2 would suffice.
Then, powering a Raspberry Pi computing device (PRPi = 4W) for an autonomous measurement device year-round at the > Neumayer III station (70.68°S, 8.27°W, Tavg,y = −15.5 °C) would prospectively require a module area of 0.41 m2, whereas at Paranal observatory (Chile, 24.63°S, 70.40°W, Tavg,y = 0.4 °C) 0.18 m2 would suffice.
Depends. If the purpose of this is to take sunlight when it’s abundant and turn it into hydrogen as a storage mechanism, then the efficiency of the exchange may not matter as much.
Hydrogen is in an economic race with batteries in storage. Hydrogen is hard to store in tanks and has a higher thermodynamic loss and the fuel cells are expensive. Batteries are big and expensive.
So the efficiency of hydrogen split-store-generate needs to beat the efficiency of store-release of the battery and the costs of the equipment.
So the efficiency of hydrogen split-store-generate needs to beat the efficiency of store-release of the battery and the costs of the equipment.
They might be in a race to win certain markets, but they are most definitely both viable in their own respects in other markets. Fuel cells will likely never be used in watches and phones, and batteries will likely never be used in widebody jets.
So far, batteries are pretty competitive on the "store energy for 24 hours" time horizon - where you need to power something at night with solar collected in the day, or evening out peaks and troughs in the electricity grid.
But it isn't yet competitive with "store energy collected in the summer for use in the winter".
For that usecase, far more energy must be stored for far fewer dollars to make it competitive vs just having a big fuel tank and a winter-only diesel generator.
Keeping lakes of water for a few months for hydropower are also competitive - the storage capacity of a big lake on a mountain top is immense.
But it isn't yet competitive with "store energy collected in the summer for use in the winter".
For that usecase, far more energy must be stored for far fewer dollars to make it competitive vs just having a big fuel tank and a winter-only diesel generator.
Keeping lakes of water for a few months for hydropower are also competitive - the storage capacity of a big lake on a mountain top is immense.
If CATL and other LiFePO battery makers get them to 200wh/kg, which they teased in 2020, and they maintain the same cycle endurance, temperature range, safety, and cost advantages, it will be a real game changer.
I've heard pumped water is like 90% efficient, but you need a gradient and space.
Does wind power decrease in winter? I also remember schemes for making a huge solar farm in the Sahara and a superconducting conduit to Europe, and that was several paradigm shifts in solar cell performance ago (15 years). But almost all large countries seem to have a sufficiently sized desert to do this with (US, Russia, China).
If solar gets good enough, and it is still on some prime parts of the economies of scale price drops, you don't care as much about long-distance transmission loss.
I've heard pumped water is like 90% efficient, but you need a gradient and space.
Does wind power decrease in winter? I also remember schemes for making a huge solar farm in the Sahara and a superconducting conduit to Europe, and that was several paradigm shifts in solar cell performance ago (15 years). But almost all large countries seem to have a sufficiently sized desert to do this with (US, Russia, China).
If solar gets good enough, and it is still on some prime parts of the economies of scale price drops, you don't care as much about long-distance transmission loss.
But we're already going to be building those batteries anyway: Electric cars.
What we need is a proper international standard for cars to be able to interact with the grid, to be able to charge and discharge based on grid conditions and pricing.
Its stupid to have everyone coming home from work at 6pm and plugging in their cars to charge right at the existing afternoon demand peak, when solar is waning. Just getting those cars to delay charging until around midnight (allowing user override) would shift a huge amount of peak demand.
Same concept if you don't use your car during the day - it should be able to discharge right into the morning and afternoon peaks, at your control. The user should be credited for this onto their car account.
It might even make sense to have dedicated high-voltage circuitry in houses and apartment blocks, to be used for EVs, solar, etc.
And we should really figure that out immediately since EV production is ramping up right now. We can't just rely on single automakers (Tesla) to work out these societal problems.
What we need is a proper international standard for cars to be able to interact with the grid, to be able to charge and discharge based on grid conditions and pricing.
Its stupid to have everyone coming home from work at 6pm and plugging in their cars to charge right at the existing afternoon demand peak, when solar is waning. Just getting those cars to delay charging until around midnight (allowing user override) would shift a huge amount of peak demand.
Same concept if you don't use your car during the day - it should be able to discharge right into the morning and afternoon peaks, at your control. The user should be credited for this onto their car account.
It might even make sense to have dedicated high-voltage circuitry in houses and apartment blocks, to be used for EVs, solar, etc.
And we should really figure that out immediately since EV production is ramping up right now. We can't just rely on single automakers (Tesla) to work out these societal problems.
If we're going to try and ramp up battery production and technology, then in for a penny in for a pound. We should really decentralize the power grid enough to take the weight of these types of spikes, putting in batteries to the home (like the Tesla wall, but with more competition) and solar/wind/gravity generation to supplement grid power generation. It's a jobs program that's been needed and called for for the last few years anyway, and now seems the time... not that the governmental gridlock would ever let anything like that happen, or even a spending project for small equity home/apartments retrofitting would happen. Not to mention the raw materials needed for the batteries.
Most of us here in CA already start charging at midnight, because of time of use power incentives. However, after using an app that showed the carbon burden of my charging, I learned that charging at midnight means I’m using relatively dirty power sources - there’s no solar at night, and the wind typically dies down.
The greenest time to charge here in Northern CA is between 11AM and 1PM, when solar production is maximum.
The greenest time to charge here in Northern CA is between 11AM and 1PM, when solar production is maximum.
Efficiency always matters; opportunity costs. If sunlight to hydrogen is your goal a novel solution has to at bare minimum be more efficient than solar PV -> electricity -> electrolyzer[0] to be useful.
[0]Known, boring technology with 99.9% of the engineering warts and technical debt already solved.
[0]Known, boring technology with 99.9% of the engineering warts and technical debt already solved.
No, it doesn't; it just has to cost less, overall. Efficiency is only a weak proxy for cost.
Not if you want to consider environmental impact.
The petrol in the ground is free, sunlight is free, biodiversity is free. The cost is only a human factor.
Higher efficiency on the other hand usually means lower resource consumption.
The petrol in the ground is free, sunlight is free, biodiversity is free. The cost is only a human factor.
Higher efficiency on the other hand usually means lower resource consumption.
Why is that downvoted ? You might have the cheapest energy source, if it's not efficient enough to meet demand without ruining the environment for humans then it's not good.
A weak proxy for cost ? Or a strong one for survival ?
A cheaper steel bike is less efficient than an expensive carbon fiber bike when your goal is to get to the mountain top before the flood submerges the valley.
A weak proxy for cost ? Or a strong one for survival ?
A cheaper steel bike is less efficient than an expensive carbon fiber bike when your goal is to get to the mountain top before the flood submerges the valley.
*unless we are talking about energy systems and therefore VARIABLE costs matter significantly.
And cost is sure not a proxy for efficiency.
It has to be more -cost- efficient, not more thermodynamically efficient.
One tends to follow the other.
Arguing that, in the judgement of process for the conversion of one form of energy (sunlight) to another (hydrogen), thermodynamic efficiency, or the measure of how well a process converts one form of energy to another isn't relevant is somewhere between obnoxiously pedantic and wishful thinking.
Funnily enough I read the article after your comment, and it is even less useful, interesting, than my initial assessment (not even direct solar to H2). It has approximately the novelty and utility of porting DOOM to <insert processor here> and running it in a refrigerator.
Arguing that, in the judgement of process for the conversion of one form of energy (sunlight) to another (hydrogen), thermodynamic efficiency, or the measure of how well a process converts one form of energy to another isn't relevant is somewhere between obnoxiously pedantic and wishful thinking.
Funnily enough I read the article after your comment, and it is even less useful, interesting, than my initial assessment (not even direct solar to H2). It has approximately the novelty and utility of porting DOOM to <insert processor here> and running it in a refrigerator.
In the real world energy isn’t always fungible. The location of the energy can be an important factor in something’s overall efficiency.
If you need the end product at a particular location, the transport costs can overwhelm any differences in efficiency.
The same also applies if you have excess energy in a particular location that you want to use.
In either case, the transport costs can make using the less efficient process, the more energy efficient choice overall.
If you need the end product at a particular location, the transport costs can overwhelm any differences in efficiency.
The same also applies if you have excess energy in a particular location that you want to use.
In either case, the transport costs can make using the less efficient process, the more energy efficient choice overall.
Exactly. Hydrogen electrolysis is most efficient at elevated temperatures, and that was a problem in some exceptionally cold areas.
This is a development that makes electrolysis practical in those regions.
This is a development that makes electrolysis practical in those regions.
>This is a development that makes electrolysis practical in those regions.
It is neither a development[0] nor does it particularly make electrolysis practical in those regions[1] (or more so than it was yesterday). Unless there is something about keeping solar cells warm that is beneficial, I'm really not seeing it.[2]
>Hydrogen electrolysis is most efficient at elevated temperatures
negligibly until you get into the realm of solid oxide cells (100's of C) -20 to +40 is negligible, and moreover a moot point because of [1]
[0]>> The method works by using electrolytes with low freezing points, such as dilute sulfuric acid, to allow the use of water at lower temperatures.
A common electrolyte for making H2, at room temperature and otherwise. Not novel (or interesting).
[1]>> resulting in an interior working temperature of around 10°C.
Approximately 30-40 percent inefficiency in an electrolyzer manifests as heat -- all they did here is wrap their electrolyzer in a blanket. Any electrolyzer of appreciable (read: useful) power has trouble keeping cold, not warm. The square-cube law applies here, electrolyzer power (and heat generation) scales w.r.t. volume, heat loss with area. For intuitive purposes, a device capable of fueling a car (driving 24/7) would be outputting about as much heat as that car's engine.
[2]There might be, (chemistry is my meat and potatoes, more so than physics), but I've always seen the issue being more with keeping solar cells cool.
It is neither a development[0] nor does it particularly make electrolysis practical in those regions[1] (or more so than it was yesterday). Unless there is something about keeping solar cells warm that is beneficial, I'm really not seeing it.[2]
>Hydrogen electrolysis is most efficient at elevated temperatures
negligibly until you get into the realm of solid oxide cells (100's of C) -20 to +40 is negligible, and moreover a moot point because of [1]
[0]>> The method works by using electrolytes with low freezing points, such as dilute sulfuric acid, to allow the use of water at lower temperatures.
A common electrolyte for making H2, at room temperature and otherwise. Not novel (or interesting).
[1]>> resulting in an interior working temperature of around 10°C.
Approximately 30-40 percent inefficiency in an electrolyzer manifests as heat -- all they did here is wrap their electrolyzer in a blanket. Any electrolyzer of appreciable (read: useful) power has trouble keeping cold, not warm. The square-cube law applies here, electrolyzer power (and heat generation) scales w.r.t. volume, heat loss with area. For intuitive purposes, a device capable of fueling a car (driving 24/7) would be outputting about as much heat as that car's engine.
[2]There might be, (chemistry is my meat and potatoes, more so than physics), but I've always seen the issue being more with keeping solar cells cool.
Agreed, compared to a novel chemical approach isolation and counterflow heat exchange seem almost embarrassingly lowtech to the mostly hypothetical "how to to electrolysis when it's cold outside" problem.
Perhaps there might be some actual merit when the end product of your process is compressed/liquefied H2? Still reads more like the usual make up some hypothetical use case for the highly impractical niche you chose to push the boundaries of scientific knowledge. But who am I to judge, I did semantic web in multi-agent systems back when ai was symbolic.
Perhaps there might be some actual merit when the end product of your process is compressed/liquefied H2? Still reads more like the usual make up some hypothetical use case for the highly impractical niche you chose to push the boundaries of scientific knowledge. But who am I to judge, I did semantic web in multi-agent systems back when ai was symbolic.
The figure of merit is cost, and it's only correlated with efficiency. If efficiency was king, we'd all be driving 60% efficient cars...the technology exists but the cost is not acceptable.
Since it uses two catalysts and controls for heat production (and loss), it must be pretty efficient, more so than straightforward electrolysis.
It can be slower to produce the gasses, though. High efficiency, low throughput.
It can be slower to produce the gasses, though. High efficiency, low throughput.
I work for electric utilities, and we've been looking at hydrogen carefully this year, but it looks to remain a niche technology for energy storage.
Hydrogen production (electrolysis, etc.) is only about 30% of the full system cost since you've also got storage and generation components. It's not likely that hydrogen will become competitive with battery energy storage since the full systems costs are very similar now, batteries are rapidly dropping in cost, and hydrogen storage and generation tech isn't getting much cheaper.
There could be a cost-competitive niche role for hydrogen through injection into existing natural gas infrastructure. But that infrastructure is already facing cost pressure from renewables.
Hydrogen production (electrolysis, etc.) is only about 30% of the full system cost since you've also got storage and generation components. It's not likely that hydrogen will become competitive with battery energy storage since the full systems costs are very similar now, batteries are rapidly dropping in cost, and hydrogen storage and generation tech isn't getting much cheaper.
There could be a cost-competitive niche role for hydrogen through injection into existing natural gas infrastructure. But that infrastructure is already facing cost pressure from renewables.
Original Publication:
Kölbach, Rehfeld, May: "Efficiency Gains for Thermally Coupled Solar Hydrogen Production in Extreme Cold", Energy & Environmental Science, 2021.
https://doi.org/10.26434/chemrxiv.14377049
Kölbach, Rehfeld, May: "Efficiency Gains for Thermally Coupled Solar Hydrogen Production in Extreme Cold", Energy & Environmental Science, 2021.
https://doi.org/10.26434/chemrxiv.14377049
Paywall free link:
https://web.archive.org/web/20210708014033/https://www.chemi...
First off this seems like a really important addition to solar in general. My impression is that hydrogen is easy to make, can be a closed water cycle (uses the same water it generates to when release the energy), and the only downside is the inefficacies of compressing it to store it among the other steps.
Does anyone know if this would be a practical source of heat say at night, considering what I understood to be Hydrogens lower energy density?
For example, I was wondering roughly how big of a tank of (I am assuming) liquid hydrogen would be required to match say 50 a gallon tank of diesel.
Or am I missing something here?
First off this seems like a really important addition to solar in general. My impression is that hydrogen is easy to make, can be a closed water cycle (uses the same water it generates to when release the energy), and the only downside is the inefficacies of compressing it to store it among the other steps.
Does anyone know if this would be a practical source of heat say at night, considering what I understood to be Hydrogens lower energy density?
For example, I was wondering roughly how big of a tank of (I am assuming) liquid hydrogen would be required to match say 50 a gallon tank of diesel.
Or am I missing something here?
There isn't a paywall I can spot in the original link - perhaps it's a regional thing?
What you might be missing here is that the "only downside" should be emphasized far more. Hydrogen is a bloody nightmare to store long term. It's boiling point makes the -20 C involved with this technology look like an oven and you really do want to ideally store it as a liquid since the exceptionally low molecular weight means leakage is a constant problem save for some very advanced (and expensive at scale) carbon composites.
Graphene seems to be a potentially excellent storage medium but we are still a while off from being able to manufacture that at the amount that would make it economically usable for hydrogen storage at scale.
What you might be missing here is that the "only downside" should be emphasized far more. Hydrogen is a bloody nightmare to store long term. It's boiling point makes the -20 C involved with this technology look like an oven and you really do want to ideally store it as a liquid since the exceptionally low molecular weight means leakage is a constant problem save for some very advanced (and expensive at scale) carbon composites.
Graphene seems to be a potentially excellent storage medium but we are still a while off from being able to manufacture that at the amount that would make it economically usable for hydrogen storage at scale.
One way to store hydrogen safely long term is metal hydrides. Hydrogen readily infuses certain metals, like lithium, like water infuses a sponge.
The problem is that the density us rather low. Enough to store tritium in a nuclear warhead, but possibly a bit bulky for home use. (Also, the hydride remains flammable.)
The problem is that the density us rather low. Enough to store tritium in a nuclear warhead, but possibly a bit bulky for home use. (Also, the hydride remains flammable.)
Titanium hydride storage has been tested for automotive use. They shot hydride tanks with a rifle, and the result was less impressive than shooting a gasoline tank.
Also, hydrogen rises quickly as it burns, instead of spreading out on the ground.
Also, hydrogen rises quickly as it burns, instead of spreading out on the ground.
Hydrogen is readily stored as liquid anhydrous ammonia.
Do you have more details on this somewhere?
Maybe a nice semi-technical writeup?
With a bit of DDGing I found something [0] from March by the chemical society. With respect to storage density, NH3 is better:
Ammonia has a higher energy density, at 12.7 MJ/L, than even liquid hydrogen, at 8.5 MJ/L. Liquid hydrogen has to be stored at cryogenic conditions of –253 °C, whereas ammonia can be stored at a much less energy-intensive –33 °C. And ammonia, though hazardous to handle, is much less flammable than hydrogen.
This doesn't even mention how elemental hydrogen weakens metals over time ("embrittlement"), which makes storage even more challenging. There are lots of other issues discussed at that link, and it's clear that NH3 will be more expensive than e.g. gasoline, at least until there is better solar power. Still, if hydrogen makes sense, ammonia makes sense.
[0] https://cen.acs.org/business/petrochemicals/ammonia-fuel-fut...
Ammonia has a higher energy density, at 12.7 MJ/L, than even liquid hydrogen, at 8.5 MJ/L. Liquid hydrogen has to be stored at cryogenic conditions of –253 °C, whereas ammonia can be stored at a much less energy-intensive –33 °C. And ammonia, though hazardous to handle, is much less flammable than hydrogen.
This doesn't even mention how elemental hydrogen weakens metals over time ("embrittlement"), which makes storage even more challenging. There are lots of other issues discussed at that link, and it's clear that NH3 will be more expensive than e.g. gasoline, at least until there is better solar power. Still, if hydrogen makes sense, ammonia makes sense.
[0] https://cen.acs.org/business/petrochemicals/ammonia-fuel-fut...
I’d rather cleanup a diesel spill than an ammonia one.
It's worth noting that regardless of this development, hydrogen fuel cells still do not work well in sub-zero temperatures unless they are operated in perpetuum.
When you decide to shut down your fuel cell and the temperature of the system drops below zero, water will freeze on your micron-thick platinum catalyst; cracking it, and rendering the entire fuel cell useless.
When you decide to shut down your fuel cell and the temperature of the system drops below zero, water will freeze on your micron-thick platinum catalyst; cracking it, and rendering the entire fuel cell useless.
How will it impact the current Solar energy sector?
Two of the major pain points were the erratic weather refusing to generate energy because of sun's availability and the storage of energy for particularly those cold areas where it was expected that entire energy for an year can be saved inside the batteries that can be generated in 2-2.5 months.
Two of the major pain points were the erratic weather refusing to generate energy because of sun's availability and the storage of energy for particularly those cold areas where it was expected that entire energy for an year can be saved inside the batteries that can be generated in 2-2.5 months.
Can someone qualified give an accurate upper bound to the potential of this innovation?
I'm not qualified, but "The technology could serve as a renewable fuel source in high altitude and polar environments" from the first paragraph of the article suggests to me that the potential is pretty limited.
I wonder about the storage though. One would need to produce during summer/polar day for use in winter/polar night - is it feasible to store large quantities of hydrogen for 6 months?
My understanding is that hydrogen likes to leak because its atoms are smaller than the atoms of anything we’d contain it with. Though there are chemical ways to store it and I’m not familiar with those.
I think reversibly combining hydrogen with nickel to form nickel hydride is one solution that's been proposed for hydrogen vehicle fuel tanks.
I suspect it'd be most practical in areas with limited heat and were other alternatives aren't as handy.
There's also a few areas where combustion engines are more practical than electric ones and hydrogen engines could be used as a stop-gap solution until electric alternatives catch up; there's only so much humanity can do at once and using combustion engines with renewable fuels could reduce emissions while we take our time focusing on other areas.
There's also a few areas where combustion engines are more practical than electric ones and hydrogen engines could be used as a stop-gap solution until electric alternatives catch up; there's only so much humanity can do at once and using combustion engines with renewable fuels could reduce emissions while we take our time focusing on other areas.
Is it common perception that "sub-zero" refers to temperature degrees below 0°C and/or 0°F?
Just as burning fossil fuels cause dangerous reconfiguration of earth's atmosphere, I think that the idea of a hydrogen economy requires careful thought. Hydrogen shares with helium a unique property, that it is at escape velocity at the temperatures of the upper atmosphere. It seems unfathomable now, but if we converted all earths water into hydrogen and oxygen without containment, the planet would become a dead rust ball. It's not that these technologies should not be pursued, merely that adopting any technology on a planetary scale, should require some incredibly serious consideration.
It's worth pointing out that hydrogen oxidizes in the atmosphere, unlike helium, so it won't escape as readily. Secondly, the Sun already splits water into hydrogen and oxygen with UV at some low rate, and that has been going on for literally billions of years from now. I don't think this aspect of what you're talking about will matter before 200 million years from now or so when the Sun becomes intense enough to kick off runaway greenhouse effect (even without human effects) unless we produce so much hydrogen (and leak it) that waste heat of civilization becomes the limiting factor.
There are other things to worry about.
There are other things to worry about.
A civilisation capable of significant depletion of the earth's oceans for the production of hydrogen and oxygen is so far ahead of us in economies of scale that we would be long past the point of needing to worry about something that could (to the point of view of such a civilisation) be trivially solved with an air wall or a secondary low earth orbit artificial magnetosphere.
I think you should look at plots of CO2 emissions over time. Life is very efficient at exploiting resources in an exponential fashion, when they become available.
I assume by "life", you mean post-industrial revolution humanity which shouldn't be treated as the norm, for either life nor even human history.
It's also irrelevant, water is incredibly abundant in our solar system and we don't even have the largest oceans on Earth, they're just the largest ones on the surface.
It's also irrelevant, water is incredibly abundant in our solar system and we don't even have the largest oceans on Earth, they're just the largest ones on the surface.
Are you saying there’s an underground ocean bigger than the Pacific?
Where is it?
Where is it?
The oceans on Europa cover a smaller area than Earth's oceans, but they contain a larger volume of water as they're much deeper.
Yes and Ganymede appears to contain concentric layers of oceans separated by layers of ice. There is also Callisto, Encaeladus, Titan, and since New Horizons, potentially even Pluto - not to mention that the trace amounts of H20 present in the sun would outweigh all of it a thousand fold.
Bottom line is that water is never in short supply. Nitrogen is likely to be the real bottleneck in our future efforts at colonisation and terraforming - at least till if/when we master star lifting of resources. At that point, mass and energy no longer make meaningful limiters and waste heat disposal becomes the primary menace to further development.
Bottom line is that water is never in short supply. Nitrogen is likely to be the real bottleneck in our future efforts at colonisation and terraforming - at least till if/when we master star lifting of resources. At that point, mass and energy no longer make meaningful limiters and waste heat disposal becomes the primary menace to further development.
It's mainly a logistics problem; there's more than enough nitrogen in the Solar system.
We just need to solve the simple problem of moving it from the atmosphere of Venus to where we want it to be. ;)
We just need to solve the simple problem of moving it from the atmosphere of Venus to where we want it to be. ;)
You're correct in the short term but Venus only has four times the nitrogen content of Earth which might sound like a lot for now but in a fully developed Dyson swarm, will prove to be inadequate. It might turn out to be a non issue since we might be able to simply transmutate it into existence by recycling more abundant materials with fusion but there is still a lot of unknowns with the actual engineering constraints of controlled fusion.
Oh, yes. If we're looking at a future where such infrastructural projects are a thing, then we'll need more nitrogen than we can get from Venus. There's also ethical concerns unless we can completely rule out the possibility of Venusian life.
The nice thing is that we got plenty of time to study Venus since we do not really even need to terraform Venus to colonise it in the short term.
At a high enough altitude, both the pressure and temperature drops to Earth's equivilent. If you have a large enough structure that is relatively airtight (it doesn't need to be perfect), you only need a small temperature gradient to keep it aloft in the upper Venusuean atmosphere.
You could have cloud cities with open air balcony areas where you can walk around with only some basic protective gear and an oxygen supply to protect against the corrosive air and perhaps enjoy gliders or other airborne amusements. It's also good practice for when we decide to attempt something similar with Saturn and some of the other gas giants.
At a high enough altitude, both the pressure and temperature drops to Earth's equivilent. If you have a large enough structure that is relatively airtight (it doesn't need to be perfect), you only need a small temperature gradient to keep it aloft in the upper Venusuean atmosphere.
You could have cloud cities with open air balcony areas where you can walk around with only some basic protective gear and an oxygen supply to protect against the corrosive air and perhaps enjoy gliders or other airborne amusements. It's also good practice for when we decide to attempt something similar with Saturn and some of the other gas giants.
I feel like proton pumps have been used by life for billions of years already and everything is mostly fine?
This would only be relevant when the fuel leaks, right? During normal combustion the hydrogen is never exposed to the open atmosphere, it is burned back into H2O and released in that form.
Losing Earth's hydrogen to space would require a stupendously long wait. Maybe freeing all of it at once would help speed the process asking, but the first lightning strike, volcanic eruption, or meteor would just ignite it all back to water. I'd be far more worried about getting struck by lighting, a volcanic eruption or a meteor, than losing our hydrogen to space.
I think scale is a really hard thing for us, but yes, being concerned about this is quite silly.
Yes. But one should be aware that leaking some hydrogen is leaking it to the outer space, for good.
This realization does not stop us from using much more rare helium in party balloons, though.
This realization does not stop us from using much more rare helium in party balloons, though.
That's not really true. Hydrogen oxidizes in the atmosphere, whereas helium does not. Also, helium is continually produced via nuclear decay in the Earth, and it seeps up through the crust. So it's rare and it leaks into space with or without humans.
The sheer amount of hydrogen you would have to put into the atmosphere for this to become a problem is enormous.
This is a problem in the same sense that the sun going red giant is a problem.
This is a problem in the same sense that the sun going red giant is a problem.
> This is a problem in the same sense that the sun going red giant is a problem
To be fair to OP, at the point we're concerned about Exxon Valdez circa 2400 dumping an atmosphere of hydrogen into space and the Sun's expansion, we could solve one problem with the other and bring the Sun's mass over.
To be fair to OP, at the point we're concerned about Exxon Valdez circa 2400 dumping an atmosphere of hydrogen into space and the Sun's expansion, we could solve one problem with the other and bring the Sun's mass over.
If we learn how to remove mass from the Sun at a large scanner, we can extend its useful life and fuse the hydrogen into more useful materials. We can prevent it from going red giant in the first place.
If we as a species develop enough to be able to electrolyze a significant enough portion of all of Earth's water for this problem to arise, it's almost a given that we have developed technologies that no longer require us to stay on Earth.
Plus hydrogen chemistry, as others have mentioned, will stop at least 99% of the losses you propose simply by reoxidizing in the presence of free oxygen.
Helium is inert and doesn't react, therefore is much more likely to be lost to diffusion.
Plus hydrogen chemistry, as others have mentioned, will stop at least 99% of the losses you propose simply by reoxidizing in the presence of free oxygen.
Helium is inert and doesn't react, therefore is much more likely to be lost to diffusion.
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I just love the thought of some silly human not putting the gas cap on correctly and whoops, we've allowed all of the hydrogen in all of the Earth's oceans to escape and now the atmosphere is way over-oxygenated and everything is always on fire.
It's like worrying that astronomers won't be able to enjoy the night sky after we've built a Dyson Sphere.
It's like worrying that astronomers won't be able to enjoy the night sky after we've built a Dyson Sphere.
I’ve seen lots of opinion here but no one has whipped out a spreadsheet and run some numbers.
Energy required to Elecrolyze the world's oceans.
Theoretical max efficiency: 13.173 MJ/kg of water.[1]
Water in the oceans: 1.35E21 kg [2]
Total energy needed to electrolyze the oceans: 1.77E22 MJ
Total energy recieved by the Earth from the sun per second: 4.3E14 MJ
Time required to elecroyize the oceans using the entire available output of the Sun on Earth at 100% total efficiency: 478.67 days
It is a very silly idea to think that we could accidentally wield many orders of magnitude more energy than humanity has ever harnessed in collective history without noticing.
[1] https://physics.stackexchange.com/questions/24624/water-elec...
[2] https://mathblag.wordpress.com/2013/08/03/how-much-water-is-...
Theoretical max efficiency: 13.173 MJ/kg of water.[1]
Water in the oceans: 1.35E21 kg [2]
Total energy needed to electrolyze the oceans: 1.77E22 MJ
Total energy recieved by the Earth from the sun per second: 4.3E14 MJ
Time required to elecroyize the oceans using the entire available output of the Sun on Earth at 100% total efficiency: 478.67 days
It is a very silly idea to think that we could accidentally wield many orders of magnitude more energy than humanity has ever harnessed in collective history without noticing.
[1] https://physics.stackexchange.com/questions/24624/water-elec...
[2] https://mathblag.wordpress.com/2013/08/03/how-much-water-is-...
It is incredible, how HN community (arguably made from some of the lest dumb people on Internet) can turn blind eye to this major concern while laughing and patting themselves on their backs.
I guess, industrial magnates of 1800s would have shown the same reaction, if someone told them about dangers of burning fossil fuels.
"This is ridiculous!", "But Sun was causing fires for centuries!" and "If it gets bad, we can stop burning more coal!" — those excuses didn't age well, yet most replies to this comment repeat them almost verbatim.
Of course, instantly sending all (or most) of Earth hydrogen into outer space is impossible — at the current technology level. But wasting what little water we have to make it is still a bad idea.
Many places are already short on fresh water — the kind of water, necessary for electrolysis. We can make hydrogen from saltwater too — after purifying it, but that's not commercially viable. No one uses "free" energy from solar panels to make new lakes or refill depleting aquifers.
Most of the Earth's surface is covered by water, but we can't even purify enough to satisfy our biological needs — otherwise Sahara would be a major agricultural and economical attraction. To solve world's water problem would require near-unlimited power, and the hydrogen production is not going to do it. At best, a hydrogen boom would result in another round of colonial robbery: stealing water from people, who can't defend it, to power more air conditioners in USA and Europe.
I guess, industrial magnates of 1800s would have shown the same reaction, if someone told them about dangers of burning fossil fuels.
"This is ridiculous!", "But Sun was causing fires for centuries!" and "If it gets bad, we can stop burning more coal!" — those excuses didn't age well, yet most replies to this comment repeat them almost verbatim.
Of course, instantly sending all (or most) of Earth hydrogen into outer space is impossible — at the current technology level. But wasting what little water we have to make it is still a bad idea.
Many places are already short on fresh water — the kind of water, necessary for electrolysis. We can make hydrogen from saltwater too — after purifying it, but that's not commercially viable. No one uses "free" energy from solar panels to make new lakes or refill depleting aquifers.
Most of the Earth's surface is covered by water, but we can't even purify enough to satisfy our biological needs — otherwise Sahara would be a major agricultural and economical attraction. To solve world's water problem would require near-unlimited power, and the hydrogen production is not going to do it. At best, a hydrogen boom would result in another round of colonial robbery: stealing water from people, who can't defend it, to power more air conditioners in USA and Europe.
> Of course, instantly sending all (or most) of Earth hydrogen into outer space is impossible — at the current technology level. But wasting what little water we have to make it is still a bad idea.
The whole point of making hydrogen (from water) to store energy is so we can release the energy later — by oxidising it back into water. We get the same amount of water back afterwards. No one is going to be stealing water to make hydrogen.
The whole point of making hydrogen (from water) to store energy is so we can release the energy later — by oxidising it back into water. We get the same amount of water back afterwards. No one is going to be stealing water to make hydrogen.
Nothing is a power system without efficiency figures. Otherwise it's just a chemistry experiment.