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by cpprototypes 3694 days ago
The energy efficiency of the process is bad, but the future economic conditions could change dramatically:

1) Fossil fuels costs will eventually start rising and never come down again. How much investment and attention will synthetic production receive when oil is $100/barrel? Or at $200/barrel, or $300/barrel? More investment could lead to significant process improvements.

2) Solar energy has improved tremendously and continues to improve more. But the great weakness of solar is that it's only effective at daytime. Anything produced in excess of daytime demand is basically waste energy. Since it's waste energy, the inefficiency of the oil synthesis process doesn't matter. The only competitor here is other energy storage methods such as batteries. The key question here will be, is it better to store this excess waste energy in batteries or use the synthetic process to make oil? From a pure efficiency standpoint, battery is better. But when considering the existing oil infrastructure, the answer is not as clear.

1 comments

The breakthrough cost is key.

One of my recent thoughts is that it's not so much that renewables are expensive as that fossil fuels are insanely under-priced, though that gets into a pretty deep economic question of just what price and cost are supposed to be.

For electrical generation, the problem with a fuel-based intermediary storage is that the net efficiency is quite low: 50% loss at fuel formation, at best 45% efficiency from thermal generation (Carnot's Law is a bitch). Fuel cell tech might offer an out, but the catalysts are rare and expensive (though if we can find an all-platinum asteroid out there, solar + synfuel + space-mined catalyst might offer advantages).

Solar costs have fallen, but the efficiency is capped. Moreover, as panel costs fall they're dominated by less-fungible elements, mostly installation and maintenance. There's the 20-year life (multiple systemic decay pathways) which means you need to replace 5% of your total stock every year.

I'm not arguing against solar, but rather, against an abudant-energy future. Even with energy issues addressed, many other factors, including literally dirt (well, topsoil), challenge humans.

Leibig's Law of the Minimum is another bitch.