Carbon Capture and Storage is necessary to keep global warming below 2°C

> It seems reality doesn't match your beliefs.

France is about 75% nuclear, Germany is about 10%

French electricity is about 2x cheaper than German, and they have much lower emissions.

Since Germany has shut down nuclear plants in favor of renewables, it has been forced to increase coal and has actually increased total emissions and accident deaths significantly.

Ontario, Canada is about 60% nuclear and its electricity prices off-peak are about 10x lower than German, on-peak about 5x lower.

Nuclear is the safest, most efficient, and more reliable energy source all nations that have it and those who have more have more affordable energy. Reality has shown this consistently for now almost 80 years.

You don't actually sequester C02 in gaseous form when you do geologic carbon sequestration.

First off, even the simplest methods wind up with it dissolved in water. You basically can't just inject gaseous C02 into the ground and have it remain a gas. The rocks you're injecting it into are filled with water and it's highly soluble in water. Under certain conditions, you can inject liquid C02 and actually displace the water already there. However, that's mostly not what's being proposed.

Geologic carbon sequestration can take a handful of different approaches. The two you'll hear talked about the most are: 1) Inject it into a reservoir where you expect it to react with something and eventually form carbonate minerals (in-situ mineral sequestration, or mineral trapping). 2) Inject it into a very deep reservoir where it will dissolve into the brine already there and/or is unable to find a way back out again due to the geometry of the reservoir. (Solubility trapping and/or residual trapping)

The first method is preferable, but actually hard to guarantee in practice. The second may sound more risky, but we're actually pretty good at identifying regions that can store a buoyant phase over geologic time -- it's exactly what we do in hydrocarbon exploration. Both are being actively explored along with several others. There's a lot of geologic research being done on carbon sequestration right now (and has been for quite awhile, actually, though the government funded it well before industry started to).

The risk of the "seed the oceans" approaches (or the olivine beach proposals as well) are the environmental side effects. Altering ocean chemistry _will_ have significant effects. Similarly, putting olivine on beaches will result in a lot of heavy metal contamination (you can't get pure olivine -- you're going to have a lot of chromite and fun other odds and ends in ultramafic rocks).

I'd argue we're better off impacting the deep underground where more or less nothing lives than we are altering the oceans.

> The higher the bar, the greater the cost. McKinsey’s analysis defines an upper cost threshold of €60 per tonne avoided (i.e. the chart only shows alternatives that are ‘cheaper’ than €60 per tonne).

60 Euros per ton doesn't seem terribly bad. Burning a gallon of gas generates about 20 pounds of CO2 (hydrogen from the gas bonds with oxygen from the air, resulting in CO2 emissions that weight about 3 times as much as the weight of the original gasoline). So, every time you refill a 15 gallon gas tank, that's about 300 pounds of CO2. I'm not sure if the chart uses metric tons (about 2200 pounds, let's say it does.

It looks like most of the CCS options on that chart are in the range of about 40 to 60 euros per ton. 60 euros * (300 pounds / 2200 pounds) is about 8.18 euros, or about 9 US dollars. That's significant; people would complain. It's not insurmountable though. People would still keep driving.

It's worth noting that the carbon capture options listed are specifically carbon capture from existing fossil fuel power plants. There may well be other carbon capture options that are cheaper, like sequestering carbon from plant biomass. (I didn't read the paper, maybe it goes into that.)

> That's a big "if" though.

No, that's pretty much how the CCS debate has been going. Norway announced a big project to cleanup a gas plant with CCS used for an oil refinery. The plant was built, but without CCS.

When Germany built its last wave of new coal power plants a common argument was that "the CO2 emissions are no big problem, we'll add CCS later". Which never happened.

The promise of CCS as an excuse for continued fossil fuel use without actually buildling it is a recurring theme in the debate.

This term "astronomical" applies no more to the scale of renewables needing built than it would nuclear. The existence of a somewhat related pdf doesn't make the prophecy realistic, that big challenges are more likely to show up for future renewable builds than for nuclear builds. The actual situation is nuclear can hardly get built currently due to "economic, regulatory, or environmental challenges" while renewables can and already have big fleet sizes.