[gersh]

There are about 37 billion tons of CO2 emissions per year. If you could get the price down to $100/ton, you can get the world net zero for $3.7t/year. US GDP is 25 trillion/year. World GPD is about 96.5 trillion. So, it would cost about 3.8% of world GDP per year. World global military is about $2.2t/year, so it would be higher than global military expenditure, but somewhat theoretically possible. If you substantially reduced emissions, it might be feasible to use carbon capture for the rest.

[alexey-salmin]

> If you could get the price down to $100/ton

That is the price of a ton of coal. Buy it from China BEFORE it gets burned and you have a sensible strategy.

Sucking it back from the atmosphere AFTER burning takes 10x more energy which is complete insanity. "Getting price down" and "when it scales" is an utter misunderstanding of the situation. Scale doesn't defeat the laws of physics.

[gersh]

So long as they have coal power plants, and need the electricity unless it get prohibitively expensive, they will just mine more coal. The way to reduce emissions is to replace high-emission infrastructure.

[rayiner]

The political and logistical problems are a far bigger challenge than energy production. Just think of all the concrete that China and India will need to pour in the coming decades and the CO2 emissions of that.

[Dylan16807]

> That is the price of a ton of coal. Buy it from China BEFORE it gets burned

And then that money funds more mines to get coal out of the ground faster.

> Sucking it back from the atmosphere AFTER burning takes 10x more energy which is complete insanity.

Part of the plan needs to be capture at power plants. Another part of the plan needs to be heavy taxes for releasing CO2. If someone needs the convenience for some use case, let them pay the capture price.

[AnthonyMouse]

I'm consistently hearing two claims here. One is that we'll have energy to do carbon capture because we may need to overbuild renewables by 3-5x to account for intermittency and then most of the time we'll have a lot of surplus power, and the other is that the only solution is for people to drastically reduce energy consumption.

Clearly at least one of these is wrong, because we can't simultaneously have a big surplus and have to reduce consumption, so which one is it?

[strken]

Why can't we have an energy surplus and also need to reduce consumption of carbon-intensive goods? It's not clear to me why they'd be mutually exclusive.

If e.g. smelters still need to use coal, then an energy surplus doesn't help them. If carbon capture is expensive even with virtually free power due to wages and infrastructure, the capture cost was reflected in the price of steel, and demand for steel is elastic, then we'd both capture more carbon and reduce steel consumption.

[hakfoo]

Part of it is the time dimension.

Electricity infrastructure used to be defined by the factories that run from (say) 9AM to 5PM. The grid has to be sized mostly for their needs, and baseload power (fossil, atomic, hydro) are sized for it, This is slow and costly to spin up and down. You see this reflected in things like utility "time of use" plans, where they offer you dirt-cheap energy at 2AM if you're willing to pay a penalty at 3PM. They'd love for you to sop up the glut by running a Bitcoin miner or chilling your house to 15C overnight.

Renewables move on a dime by comparison. If we need n GW of power at the peak time of 5PM, depending on the yield factors of local solar/wind/tidal/etc, we may end up with an infrastructure that generates 3n or 5n at other times of day. A lot of thinking has gone to batteries/molten salt/pumped hydro as ways we can store that surplus for later needs, but we can also direct the glut into processes that are energy-intensive and only economically viable in a power-too-cheap-to-meter scenario.

The CO2 scrubbers could be a viable sink for that excess power once we've got enough grid-scale storage.

[AnthonyMouse]

Isn't the cost of that plus the cost of operating the fossil fuel emitting infrastructure significantly higher than the cost of other known alternative power generation methods?