Comment by dredmorbius

It's possible to synthesise hydrocarbon analogues of petroluem-based fuels. The problem to date has been that this isn't cost-competitive with petroleum, though the difference is narrower than you might expect. Most famously, a Google X Project attempted this and succeeded technically, but the economics were unfavourable: Project Foghorn: <https://x.company/projects/foghorn/>. Both Germany and South Africa have performed synfuel production (from coal) at industrial scale since the 1930s / 1950s, respectively. Using non-fossil carbon is largely the same chemistry; the process does in fact scale.

Fischer-Tropsch and Sabatier process can both operate with scavenged CO2. There's been some work since the 1990s utilising seawater as a CO2 source, with CO2 capture being far more efficient than from atmospheric sources.

Whilst hydrocarbons have numerous downsides (whether sourced from fossil or renewable sources), they are also quite convenient, exceedingly well-proven, and tremendously useful. In some applications, particularly marine and aviation transport, there are few if any viable alternatives.

I've commented on this numerous times at HN over the years: <https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...>.