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An interesting detail is that a CO2 pipeline may be a little more dangerous than a methane pipeline.

Methane is lighter than air and leaves the scene quickly; even if it catches on fire the flames are high above the ground and radiate a lot of heat to space, where early-warning missile launch detection satellites will tell the world you screwed up in a few minutes. Unlike a solid material fire on the ground it doesn't create brands that fall down and start more fires in other places.

CO2 on the other hand will sink into low spots and could possibly suffocate people.

CO2 pipelines, for one thing, will need many more shut-off valves when they pass near populated areas.

Doesn’t sound exactly like the poster child for carbon capture (which I believe we need in some form). For one, ethanol — I would have to double check this but last time I looked, ethanol represent a very tiny sliver of the energy pie.

But again, as someone who calls themselves an environmentalist, I do think we need to be putting serious thought into capture, because I don’t think we’ll want to live with current levels of warming, let alone where the trajectory has us winding up even in best case drawdown scenarios.

The advantage of tying carbon capture to an Ethanol plant is that you get very pure carbon dioxide as a waste product of the fermentation process.

If you want to capture carbon from combustion you need to separate the carbon from both water and nitrogen; you have to compress carbon dioxide to about 1500 psi to inject it underground and even a few percent of contamination will cause the gases to phase separate in the pump and in the pipeline and cause no end of trouble.

The "gold standard" for purifying carbon dioxide from combustion is

https://en.wikipedia.org/wiki/Amine_gas_treating

and that involves an expensive stock of amines. You might be able to lower the cost of purifying the gas by separating oxygen from nitrogen before burning the fuel, but you not only need to pay to do that, but you need to recycle the exhaust gases otherwise the temperatures will get too high and burn up your turbine.

When you capture the carbon from a biofuel plant you are capturing it from the air and putting it underground opposed to a plant that burns fossil fuels which merely prevents carbon from entering the atmosphere.

For all of those reasons, adding carbon capture to Ethanol plants is a good way to get practice at the storage part of CCS.