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Comment by Tade0 | Hacker News Reader

> All you need is napkin maths. We gain energy by turning carbon into carbon dioxide. Now, we need the same energy to reverse it, but with a loss factor.

I'm of the opinion that no matter the level of cartoon villainy the oil industry is accused of - they're most likely guilty, but there's an inaccuracy here:

In hydrocarbons the majority of energy comes from the oxidation of hydrogen.

We should get rid of coal first, as it's irredeemable in this regard and methane second, as it's a greenhouse gas which tends to leak, but it's theoretically possible to burn hydrocarbons and turn the CO2 to coal and leave it like that with a net energy gain - it's just hugely impractical compared to not burning them in the first place.

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> In hydrocarbons the majority of energy comes from the oxidation of hydrogen.

This I wasn't quite aware of. Thanks for the correction.

> But it's theoretically possible to burn hydrocarbons and turn the CO2 into coal and leave it like that with a net energy gain

This would be a game-changer! Though "theoretically" is pulling a bit of weight here...

> We should get rid of coal first, as it's irredeemable in this regard and methane second, as it's a greenhouse gas which tends to leak,

I also agree with your list. Burning stuff for grid energy should stop ASAP. Liquid fuel for transport is, however, the most difficult and probably the last to be replaced. It's to the point that generating green liquid fuels (that don't use fossil sources of carbon) is still actively researched and used, as air travel or shipping may never become feasible on green energy sources.

Ever see a diesel 'rolling coal'? They are burning the hydrogen and sending carbon into the air. Terrible for the local evironment though. this is still carbon positive though since some carbon is burned - just not all.

> But it's theoretically possible to burn hydrocarbons and turn the CO2 into coal and leave > it like that with a net energy gain

> This would be a game-changer! Though "theoretically" is pulling a bit of weight here...

In nat. gas this is possible - its called pyrolisis - as an alternative to steam reformation it is generating pure carbon and hydrogen instead of the CO2 and Hydrogen that steam reformation does.

Its main downside is that it takes more energy so you get less usable energy out of the process.

You can do it with other organic fuels as well and the simplest process is making charcoal from wood but its not as clear a way to separate out carbon there.

> Burning stuff for grid energy should stop ASAP.

Sadly I think the only viable route to this is wealthy countries paying poor countries to dismantle these power plants (and presumably replace them with something equivalent).

This has two nice benefits. One, wealthy countries show they act in good faith. Two, this will greatly reduce wealth disparity.

Of course, there's the chance some people will threaten to emit gas to acquire disproportionate power. This is true, but still preferable to the west just roasting the planet and then blaming china. Like grow tf up.

This is putting the cart before the horses. These wealthy countries haven’t even stopped burning fossil fuels. Let’s focus on that first.

Why not both? We've been claiming to want to reduce carbon emissions since before I was born. It's not even a hard pitch—if we're insanely wealthy and have the capacity to discuss greening our grid and still can't or won't, why would you reasonably expect countries with basically no capacity to do this to forget about centuries of globalization, colonization, and exploitation? We burned the globe; if we want to heal this, the most reasonable approach is good-faith reconciliation and remediation.

But the way conversation is now we're headed straight towards ecofascism. A healthy globe for me but not for thee (as if this even makes much sense).

You're right.

It's convenient for the US to blame "developing economies" (especially China) for the problem. Solutions like "buying off other countries" make sense. (And in itself is not a bad idea.) But it's a deflection from the bigger issue which is consumption at home.

But as long as we can make it a "them " problem, our population doesn't have to feel guilt, or understand they are the people who need to change.

Sounds good I'm theory but tough to put into practice. Regardless of the environmental consequences there is no way that voters in wealthy countries will agree to subsidize hostile regimes. And many of those countries are so deeply corrupt that the majority of funding tends to be stolen by corrupt politicians or building contractors.

>wealthy countries paying poor countries to dismantle these power plants (and presumably replace them with something equivalent)

And what about wealthy countries, that using those power plants? I mean there aren't many of them now, but have you been communicating with Europeans recently? Not with the privileged elites in the universities, but with the working class Europeans? There are so many complaints about energy prices that I'm afraid even there democracy can't be thwarted anymore and we'll see burners all over Europe in like 10 years from now.

The working class should complain, that's their role in liberal democracy. Better complain about energy prices than armies of invading muslim rapists.

This might be less of a problem than you would expect.

Pakistan, for example, is currently experiencing a massive solar boom. Their electricity grid has been notoriously unreliable in the past, so the moment solar panels and batteries became cheap enough just about everyone chose distributed solar. It is now the world's sixth-largest solar market, despite having the world's 42nd-largest GDP.

The goal in poor countries isn't dismantling fossil fuel plants - those never grew beyond a rounding error. The goal is to avoid building new fossil fuel plants as their economies grow, and that's a lot easier now that solar has become the cheapest source of electricity. Their old power plants will eventually close down, but it's not a priority on a global scale.

shipping may never become feasible on green energy sources

If only we had some historical records explaining how pre-industrialized societies navigated the globe without fossil fuels...

Did those societies feed and clothe billions of people?

China has started adding battery electric container ships to it's local shipping fleets. They have also started using some battery electric cargo trains. Now if they can just get off coal for their electricity consumption they are very close to the tipping point. So in my opinion we are getting there in terms of carbon output but I also think it is to late to stop global warming and we have crossed the point of no return already.

https://electrek.co/2024/05/02/fully-electric-10000-ton-cont...

There's still a ways to go, but China are progressing faster at this than the US is.

https://www.reuters.com/business/energy/chinas-solar-wind-po...

While the US looks at China as the convenient villan here, the rest of the world sees the US as the villan and China at least aggressively attacking the problem.

And that's before we consider the impact Chinese exports of solar panels and inverters have had on renewable energy production outside of China.

One may not like the system of govt in China, or their human rights policies (personally, I don't, but each to his own), but as far as climate change goes they're getting stuff done while the US govt does nothing. Or actively fights against improvements.

China is demonized in the western countries for human rights abuses only because it is a communist country I am not saying that China is not doing bad shit but that western countries hypocrisy of only highlighting China. Where as they themselves have exploited and are still exploiting African countries resources by using corrupt African politicians that are doing many human rights on their people. At least Europeans have started to at least call-out Israel now but they should also call out US for enabling Israel but for those abuses it's okay not to say anything to the US.

China is also heavily exploiting African countries by using corrupt politicians.

I hear that a lot and maybe it is, but I can't see how it squares with numbers like these

https://ourworldindata.org/co2/country/china

Decades ago, coal was said to be in terminal decline. Years ago, coal was supposed to be economically dead due to being more expensive than renewables. Today we have yet to hit global peak-coal, China emits more CO2 than all western countries combined now, its emissions per-capita are higher than all but a handful of developed countries, and they are continuing to spike alarmingly. China is also home to some of the cheapest and most abundant renewable energy generation manufacturing in the world. Something isn't quite adding up.

> coal was said to be in terminal decline

It was maybe "said" ... There seems to have been quite a bit of groupthink (or propaganda) over the decades that new energy sources would supplant old and it's never been really accurate. AIUI, wider use of oil created more demand for coal, wider use of renewables creates more demand for oil and so forth, because amongst other things new energy production puts greater demand on existing sources, plus the new-lanes-on-the-highway tendency of late capitalism to put all of it to work making the rich richer etc.

Renewables aren't "new sources" by now though. They are existing sources. So if production demands more energy and renewables are the cheapest existing sources of energy, then you would build more renewable generation, not more coal generation.

I think what actually happened is that people with agendas pushed this deception to fool people into acting and voting against their own best interests.

My comment was more based on recent reading about the relationship between oil and coal (https://www.theguardian.com/environment/2013/apr/17/why-cant...):

> But oil didn't displace coal, it helped us mine it more effectively and stimulated more technologies that raised energy demand overall. So coal use kept rising too – and oil use in turn kept increasing as cleaner gas, nuclear and hydro came on stream, helping power the digital age, which unlocked more advanced technologies capable of opening up harder-to-read fossil-fuel reserves.

With renewables I agree it isn't the same. What is the same is we're only going to get out of this by turning away from growth-at-all-costs mentality. For instance, this article describes how the Gulf states are making huge investments in renewables _to sell more oil and gas_ (https://www.tni.org/en/article/a-transition-to-where-the-gul...):

> The Gulf states see no contradiction between an embrace of ‘low-carbon solutions’ and pursuing the path of accelerating fossil fuel production ... With very high levels of energy consumption at home, the domestic substitution of oil and gas with alternative energy sources means that more fossil fuels can be made available for export. Indeed, such reasoning is explicitly behind Saudi Arabia’s plan to generate half of the country’s electricity from renewables by 2030 ...

That article is 10-11 years old a lot has changed since then.

> it's theoretically possible to burn hydrocarbons and turn the CO2 to coal and leave it like that with a net energy gain - it's just hugely impractical compared to not burning them in the first place.

It's also theoretically possible to have chemical reactions that bind carbon from the air into solid compounds that aren't themselves combustible without a net energy loss, but then you need a very large volume of reactants and produce a very large volume of industrial waste and it still turns out to be highly uneconomical compared to the cost of replacing fossil fuels for power generation.

> It's also theoretically possible to have chemical reactions that bind carbon from the air into solid compounds that aren't themselves combustible without a net energy loss

That's not true. The reactants must have enough stored potential energy to reduce carbon. You might get that for "free" by using accelerated weathering of rocks (the energy ultimately comes from the radioactive decay in Earth's core).

"Net energy loss" meaning you have to supply some energy in the form of heat or electricity to make the reaction go, and you don't get it back.

There are things that will react with CO2 and form something that isn't combustible. That reaction may even generate heat that you could hypothetically use for something, but in practice probably not enough of it to be worth extracting.

> There are things that will react with CO2 and form something that isn't combustible.

Sure. There are plenty of such things. For example, elemental magnesium will happily bind carbon dioxide into pretty inert magnesium carbonate. But to _get_ that elemental magnesium, you need to expend energy, because elemental magnesium can't be found in nature.

There is only one realistic option: rock weathering. Silicate rocks can react with carbon dioxide to produce calcium carbonate and (eventually) silicon dioxide.

> In hydrocarbons the majority of energy comes from the oxidation of hydrogen.

That's not quite true.

To add some numbers, the average formula for long-chain hydrocarbons is roughly CH2 (one carbon atom for two hydrogen atoms). The enthalpy of formation of water is -286kJ/mole, and for carbon dioxide it's -394kJ/mole.

Conveniently enough, one mole of long-chain hydrocarbons produces one mole of water and one mole of carbon dioxide.

It's better for pure methane, as with its formula CH4 it produces 2 moles of water for each mole of CO2. So you get 572kJ of energy from hydrogens versus the same 394kJ from carbon.

Formation is just one part of the equation. On the other side there's an additional C-C bond per segment of the hydrocarbon chain longer than methane, which you need to break during combustion.

It's already taken into the account. The CO2 enthalpy of formation has C-C bond breaking "baked in", by convention the "standard" form of an element has zero enthalpy of formation. For carbon, it's graphite with its C-C bonds.

I did neglect the C-H bond enthalpy, but it's close enough to the C-C bond energy to matter too much.

> I'm of the opinion that no matter the level of cartoon villainy the oil industry is accused of - they're most likely guilty,

Unfortunately their success over the years is showing others like the airline industry how to behave. There's some great "support" getting cloud into the extreme left (who are anti science like the extreme right) who conveniently love talking about chem trail style nonsense... Which is a shame because if we actually made an effort to reduce these clouds we'd make a big step forward to improving things for little effort... (Notice how I'm not saying fix, we're closer to fusion at scale than battery powered commercial flights I suspect)

> There's some great "support" getting cloud into the extreme left

Is this sentence missing a word or is it a use of the word “cloud” that I don’t know?

There's a pretty insane scheme called "underground coal gasification" which had been proposed for the Firth of Forth. It's the same process as town gas - partial oxidation of coal to hydrogen and carbon monoxide. Bus in situ. So a controlled underground coal fire.

There's a similar idea to gasify old oil and gas wells. This sounds more feasible than doing it with coal though I suppose you could have a blowout. It should be cheaper too since it uses already drilled wells.

https://protonh2.com/protonh2-advances-project-apollo-with-s...

Are you telling me that you're against good clean American coal?! https://www.theguardian.com/us-news/2025/feb/03/trump-war-on...

(BTW I agree with you, but the current political climate - and not only in the US - seems to go in the entirely wrong direction)

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