[Dylan16807]

> So the only question we need to ask is if it’s easier to cut emissions or sequester them.

At the start, cutting is much easier. But each percent is harder to cut than the last. There is a point where cutting costs more than sequestering.

[AnthonyMouse]

> At the start, cutting is much easier. But each percent is harder to cut than the last.

That isn't necessarily true. Solar panels are less than 5% of the price they were in 1990. Economies of scale reduce costs. There is a clear path to fully decarbonizing the power grid without raising energy costs using some combination of renewables and nuclear -- France has already done this. Nearly all of transportation and heating could be electrified.

You don't get into significantly higher costs until you get near the end. Biofuels would function for aviation but would raise the price if no one can come up with anything better. Cement emits CO2 and it's not currently obvious what to do about it. But if you would e.g. institute a carbon tax, it's not implausible that the market would find a more efficient alternative that isn't currently known.

It doesn't make sense to spend resources on capture until it costs less than the alternatives, and it's not implausible that it never will.

[Dylan16807]

I'm not just talking about the grid. Consider airplanes. Figuring out either biofuel or carbon capture that 90% of flights need is a lot more difficult than making a car electric.

[AnthonyMouse]

The vast majority of CO2 emissions are from burning fossil fuels to generate heat/energy on the ground. We already know cost effective alternative ways to do that. That's ~90% of the way there with no increase in costs.

We don't really have to "figure out" biofuels. They exist and are only moderately more expensive than fossil fuels. Institute a carbon tax and planes would run on biofuels and have 20-50% higher fuel costs, possibly less if cheap renewables lower energy costs in general and thereby the production cost for biofuels. On top of that, if petroleum fuels were only being used for aviation they might have lower economies of scale and higher prices, making biofuels more competitive.

One of last big things we still need to figure out is what to do about cement. But even there half of the CO2 attributed to it is energy use rather than the chemical process, which could be switched away from fossil fuels. Then we could use less concrete and more wood or steel. Or someone might come up with a cost effective alternative to cement in concrete. The incentive to do all of these would exist with a carbon tax.

The market is going to do whatever is most cost effective, even if it's only more cost effective by a modest percentage. But then all you need is a modest percentage in carbon tax and you're done.

[Dylan16807]

I'm not sure what you're arguing here. If you think 90% is pretty easy but 10% isn't then that's not in conflict with what I said.

I wouldn't say that all of that 90% is equally easy. There are challenges that increase as more power is made from solar/wind, and there are different challenges to making enough nuclear.

[AnthonyMouse]

> If you think 90% is pretty easy but 10% isn't then that's not in conflict with what I said.

It is though, because the 80th percent isn't any harder than the 5th percent, and may even be easier because when you're just starting out you don't have economies of scale.

You don't get to the hard part until you're almost entirely done and only left with the few outliers that are unusual and expensive to address.

> I wouldn't say that all of that 90% is equally easy.

That's true, but it could just as well be because they get easier.

Getting a new nuclear reactor design through the NRC is a massive ordeal, but once you have you can build an unlimited number of them without having to do it again.

> There are challenges that increase as more power is made from solar/wind, and there are different challenges to making enough nuclear.

As an absolute baseline we could replace the entire grid with nuclear. This is a known technology. If we wanted to we could build a thousand more reactors using known designs that are already in use and it would work. France has basically done this; they have a 70% nuclear grid and most of the rest is hydro and renewables. Their energy costs are below the EU average.

The only reason to do something else is if the other thing costs less. Newer reactor designs or regulatory reform could lower the cost relative to existing nuclear reactors. Using new renewable infrastructure to charge electric vehicles is an obvious fit because they have built-in storage. Solar aligns well with air conditioning load. If economies of scale lower the cost of storage technologies it could allow for more renewables and less nuclear. But these are all things that could make the price lower rather than higher.