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namibjtoday at 7:08 PM0 repliesview on HN

Just use any carbon monoxide source (e.g., pyrolysis of pretty much anything that'd release carbon dioxide when burned works, followed by some cleaning to get rid of some problematic catalyst poisons (notably sulfur compounds)), add hydrogen, and do Fischer-Tropsch. You get your high quality diesel fuel, often higher quality than what you can easily get from crude oil, btw.

If you don't have anything to pyrolyse, use a sodium or potassium hydroxide wet scrubber to extract it from ambient air and recover it from the solution with burnt lime; it preferentially bonds to the carbonate, becomes nearly insoluble; you take the lime stone powder, heat it with a high temperature blow dryer until the carbon dioxide cooks out (you can use pure carbon dioxide atmosphere for that! Just let out excess buildup of CO2 pressure to your output cooler/storage.), have regenerated the burnt lime, take the resulting CO2 and hydrogen to perform water gas shift to turn the mix into CO and H2O, condense out the H2O, then use the CO + H2 mix for your Fischer-Tropsch synthesis.

You can use incineration facilities to tap off concentrated CO2 and mine landfills until they are empty to keep the incinerators fed to get the CO2 possibly-cheaper than from the direct air capture units.

Start by using more solar cell glass laminate for exterior surfaces of new construction and as roofs over whatever parking lots you do want to keep around longer-term.

Synthetic non-fossil fuel is going to need plenty of electricity and probably much of that "just" to electrolyze water into hydrogen which is reasonable for seasonal energy "storage" (run them during the high-solar 25~50% of the year, use underground caverns (former natural gas wells) or liquify it to store for the winter, run the synthesis plant that consumes it year-round. Don't just burn the hydrogen in power plants, though you can keep existing fossil fuel plants around for a while to run them during the worst week or two of an average winter. But expect the power to be as expensive as each kWh you get today from a small gasoline generator fueled with fully-taxed highway gasoline...