Pure hydrogen is heavy greenwashing - after many years talking about green generation, still over 90% is created from natural gas, by the usual fossil fuel companies; they are also the ones promising to build the green hydrogen factories, by the way. It is indeed barely suitable for (direct) consumer use and highly inefficient for electricity generation (like 10% efficiency iirc).
this post was submitted on 19 Apr 2024
138 points (97.3% liked)
Climate - truthful information about climate, related activism and politics.
5245 readers
302 users here now
Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.
As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades:
How much each change to the atmosphere has warmed the world:
Recommended actions to cut greenhouse gas emissions in the near future:
Anti-science, inactivism, and unsupported conspiracy theories are not ok here.
founded 1 year ago
MODERATORS
Long duration energy storage efficiency with hydrogen is closer to 40-45%. It is feasible and a good option in certain grid applications.
By God, just get an electric stove like the rest of the world.
Induction burners are amazing and I don't know why they're not the standard.
hydrogen blends [...] compared to gas
I get the jitters reading that. They're both gases. Is it so hard to write "methane"?
I mean if someone says they have gas central heating I wouldn't question which gas it is. In context I think it makes perfect sense. Feels a little pedantic tbh.
It might be propane. Indeed very unlikely for central heating. But pretty likely if they're cooking with "gas".
They're both gases, but when somebody says they have a gas heater, I'm not about to ask if it's xenon powered
I'm very confused. About a year ago I saw a YouTube video describing the use of hydrogen as a replacement for fossil fuels.
It went into great detail about the effectiveness and impracticable restrictions on distribution of pure hydrogen, mainly because its extremely small molecules leak through pretty much everything and compression is required to carry any useful quantities around, not to mention storage temperature and refuelling issues.
This was contrasted with using ammonia as a hydrogen delivery mechanism instead. We distribute and transport ammonia around the planet in great quantities already. The chemical process is green, uses significantly less energy, and we already know how to do this.
What I don't understand is why we're still talking about pure hydrogen, doing studies about cooking and still trying to promote this as a great fuel, when better, more effective ways exist.
Anyone?
More information here: https://news.northwestern.edu/stories/2020/11/ammonia-to-green-hydrogen/
This article is specifically talking about the use of hydrogen blended into natural gas pipelines as a way to reduce dependence on fossil fuels for heating and cooking. Ammonia as a transport mechanism has no place here.
The current consensus in the industry is that you can replace up to 20% of the natural gas with hydrogen in a pipeline with no adverse affects. This article is indicating that there may in fact be some adverse affects.
Edited to fix some stupid autocorrects. At least it was mainly verb tense this time.
Ammonia is nasty stuff. From a safety perspective I'm sure we'd be better off building new nuclear plants than increasing the usage and transportation of fry your lungs sauce.
Youtube videos often gloss over the details for the sake of uninhibited futurism.
Large-scale hydrogen electrolysis has a cost of around 55kWh/kg, and when you combust the H2 directly you get about 39kWh/kg back. Without compression/transport, using H2 as a heating fuel is 71% efficient.
H2 is usually compressed for transport. Compression of 1 kg of H2 to 700 bar costs about 5kWh of additional electricity. I'll spare you the calcs, but truck transport is under 1kWh/kg H2. This reduces our efficiency to 39kWh/61kWh or 64%.
Converting H2 to ammonia takes the place of the compressor and truck. 2 mols of ammonia burn for 162kcal, less than the 204kcal you'd get from 3 mols of H2. The Haber-Bosch process reduces output to 31kWh per kg of H2 put in. This reduces out efficiency to 31kWh/55kWh or 56%.
With currently-proven cracking technology, it costs around 23kcal/mol of ammonia, reducing overall efficiency to about 55%. It is more effective to burn ammonia directly than to convert it into H2 and burn the H2.
Using ammonia as a transport medium removes a bunch of technical problems, but it introduces new ones. It's corrosive, it's toxic, it burns eyes/lungs/skin, and it wastes more energy than you'd think.
Ammonia is an environmental hazard, in addition, the chemical processes, however green they may be, need extra energy compared to production of hydrogen. And that is already a very lossy process, energy-wise. You also need infrastructure for it. Afaik, only Japan is really interested in building such infrastructure.
One possible reason is that ammonia is a fairly dangerous substance with both acute and chronic exposure risks.
The study hasn't been peer reviewed, so shame on the authors for talking about it like it's already decided, but the skeptical part of me can't rule out that this whole thing was destined to fail on purpose.
Big Oil: "See? Hydrogen doesn't work ~~in unmodified systems~~! Shucks, guess we'll have to keep using natural gas..."
And maybe it's less nefarious, like additional proof that we can't just retrofit existing systems by changing the gas mixture, but it's at least suspicious that it benefits fossil fuel producers so neatly.
Big oil has been the primary force pushing hydrogen, because they make most of it, from cracking fossil fuels products. It's complete green washing.
In terms of chemically bonding hydrogen to something else for easier storage and transport, I think the best plan is to add carbon so it becomes convenient synthetic methane or gasoline that we can use in our existing distribution infrastructure and machinery.
...of course, that just goes to show how absurd the entire concept of hydrogen is, considering that it's almost exclusively made from those things in the first place!
If we really want a sustainable portable energy storage medium that isn't electricity, my vote would be for cracking water into hydrogen with electrolysis and then immediately (in the same facility) converting that + CO2 to synthetic hydrocarbon fuel using the Fischer-Tropsch process.
Why was this even a question? Of course hydrogen leaks like crazy when you just put it in existing methane pipes. Hydrogen is notorious for leaking through the smallest faults and our existing infrastructure is ancient and just not designed for it. Hell, my house still has threaded and doped iron gas pipes and that is not at all uncommon in the US even on the main grid. If you want to use hydrogen instead of methane then you need to replace all of our gas pipes with brazed or welded pipes and replace all of our gas appliances with appliances designed for use with hydrogen.
As much as I love my gas stove, that just isn't practical. The only way I can see us continuing to use existing gas infrastructure in a somewhat environmentally friendly way is if we made synthetic methane in mass with electrolysis produced hydrogen and atmospheric CO2 via the Sabatier Process. Hovever that is a horribly energy intensive process so unless cold fusion suddenly becomes a thing or something I doubt that will ever happen. Even then it would still be nowhere near as practical as just switching to electric appliances.
....or you could just, you know, not use gas.
I know it's upsetting to some folks but the health concerns are wild (especially if you have kids in the house, seriously) and it's use and the leaky infrastructure pour too much into an already overburdened env.
seems like the logical move.
That's why this was the last thing I said in that text wall.
Even then it would still be nowhere near as practical as just switching to electric appliances.
As much as I love my gas stove and my water heater that needs no electricity, I do acknowledge that they need to go at some point. I'm personally waiting for heat pump appliances to get cheaper or for my finances to get better so I can afford them. Heat pump water heaters and driers are far more efficient than their resistive electric counterparts. Decent induction stoves are also too spendy for me right now.
There is some nuance here. The efficiency of electric depends partially on how it's produced, and if (emphasis on IF) your local power station burns fossil fuels, and what you're after is heat, then burning the gas inside your house is (generally) far more efficient than burning it in a power station to generate electricity that you then turn back into heat inside your house. There are exceptions, but
Of course the best thing to do is to turn renewable (or long-lasting) forms of energy into electricity. The sun ain't gonna stop shining, the wind ain't gonna stop blowing, magma ain't about to get cold, and those spicy rocks are gonna stay spicy. There's no reason for us to be turning carbon into heat into electricity and back into heat in current year.
I'm fortunate that the vast majority of our power comes from hydro.
I hope we can convert to wind and solar before that snow melt ends.
It was a question because the methane gas utilities tried to promote it as a means of creating social permission to continue extracting and burning fossil methane. Making the point that it's a bad idea is a way to push back against that.
Hydrogen leaks more than gas
Hydrogen is a gas. Gotta be more specific.
Wasn't this basically the plot of Glass Onion?
...how the fuck is hydrogen going to pollute more than the regular fuel gas if hydrogen is everywhere in the universe and this world? Omg.