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353 points dmazin | 2 comments | | HN request time: 0s | source
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Biologist123 ◴[] No.44510157[source]
This was a great positive start to the day. Thanks whoever posted that.

One point curious in its omission is whether the growth of renewables outpaces the depletion of our carbon budget. Presumably that’s the critical metric in all of this.

[Edit: I ran this question through ChatGPT and the initial (unvalidated) response wasn’t so exciting. This obviously put a dampener on my mood. And I wondered why people like McKibben only talk about the upside. It can sometimes feel a bit like Kayfabe, playing with the the reader’s emotions. And like my old man says: if someone tells you about pros and cons, they’re an advisor. If someone tells you only about pros, they’re a salesman.]

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alex_duf ◴[] No.44510297[source]
>whether the growth of renewables outpaces the depletion of our carbon budget

I'm not sure I understand. There's no carbon budget, any carbon that we emit is carbon we'll have to re-capture somehow and the longer it stays in the atmosphere the longer it will have a heating effect.

I think renewable have accelerated to the point of matching the electricity growth worldwide: https://ourworldindata.org/grapher/electricity-production-by...

We've also passed the peak of CO2 per capita, but since the population is still growing we are still increasing carbon emitions worldwide. It's going to be a while before we stop emitting anything, and then longer before we start re-absorbing it...

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myrmidon ◴[] No.44510573[source]
I highly doubt that we will have global negative emissions (CO2 capturing) within the next decades-- maybe by the end of the century.

Even very rich nations have a handful of prototype plants for CO2 capture right now at best, and the budget for things like this is the first thing that gets slashed by Doge et al.

If we were on track for lots of CO2 capture by 2050, we would see the beginnings already (massive investments, quickly scaling numbers of capture sites, rapid tech iteration).

Fully agree with the rest of your point though. I consider CO2 emissions as basically "raising the difficulty level" for current and future humans (in a very unethical way, disproportionately affecting poor/arid/coastal nations).

I'm also highly confident that human extinction from climate change is completely off the table (and I think a lot of people delude themselves into believing that scenario for no reason).

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fpoling ◴[] No.44517406[source]
If electricity is sufficiently cheap it can be cheaper to capture carbon from the atmosphere for chemical industry than to use oil or coal there.
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VBprogrammer ◴[] No.44517921[source]
Do you have any source for this extraordinary claim? It's practically a claim of perpetual motion.

Carbon dioxide a tiny fraction of the atmosphere, even in concentrations which are immediately harmful to human life.

At the moment it's 400 parts per million. So in order to extract 1kg of Carbon Dioxide from the atmosphere you have to pump 2500kg of air through the system. This alone makes it unlikely we can do this profitability.

You then need to extract the carbon dioxide using some technique which will probably involve cooling or pressuring that volume of air. Before finally transforming carbon dioxide, a very stable chemical compound, into a reagent which is actually useful (probably carbon monoxide).

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hnaccount_rng ◴[] No.44522538[source]
It may never be “worth” it in economic sense, but it offers a way to separate the time of “energy is used” and “energy is available”. Assuming sufficient captureable volume you could capture the emissions of a fossil power plant during the ~two weeks per year where weather is sufficiently bad. And then take the other 50 weeks to capture that carbon again. It can be completely inefficient (like sub 5% round trip efficiency) if a) we pay for it via a capacity market and b) have sufficient excess (clean) energy to run it
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1. VBprogrammer ◴[] No.44529644{3}[source]
The idea that we'll have huge excesses of clean energy seems like wishful thinking. We may have issues with excess energy at certain times of day for sure. But intermittent excesses like that are difficult to make use of economically because of capital costs and low utilisation. A general excess would be countered by falling energy prices to the point that it's difficult to make a business case for new installations.

I don't see a future where technologies which are massively inefficient reach their break even cost before other energy intensive activities or more efficient grid scale storage soak up the excess.

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2. hnaccount_rng ◴[] No.44540017[source]
Of course it seems like wishful thinking! Because that’s the historic norm. Energy was (in some way) always the limiting factor. And every time energy access got meaningfully cheaper society massively reorganised around it.

And yes “energy” in general won’t be free. We still need to build the generation and distribution systems. But we reached a point where just dumping solar on all _new_ roofs rounds to essentially free (the costs are the labor and the access to qualified personnel). The exact same is currently happening to batteries. Any transformer project will be able to just integrate 4-12 hours of batteries without getting meaningfully more expensive. The same for every domestic or industry service upgrade

We are not there yet. But give it another 5 years and we will. And then we are only talking about financing what little distribution system we will need (basically you only need average-sized cables not peak-sized ones) and a capacity market for backup power systems (also only for average residual demand). And those we simply cannot (efficiently) finance by a per-kWh-used charge