I've seen a bunch of these over the years; still waiting for one that will get traction. The changing cost of oil (mainly making externalities fiscally concrete) may change the equation.
The most interesting I ever ran across was people doing artificial photosynthesis to produce H2 and combustable oil, e.g. Nate Lewis' group at Cal Tech. Same problem: contemporary economics.
I'm glad people are still working on these problems.
The problem is energy conversion efficiency. Sure you can make synthetic jet fuel from solar panels, water and CO2 but the efficiency is miserable[1]. It's something like 4% efficient and the metal catalysts sometimes aren't cheap. I guess it's important to start somewhere and work on efficiency improvements until it makes economic sense.
The 4% efficiency is starting from sunlight. This overstates the case, because any solar scheme wastes most of it. That doesn't mean solar energy is impractical, any more than the roughly 1% conversion (if that) of sunlight to food calories in a farmer's field would make agriculture impractical.
Also, that scheme is a thermochemical scheme for sunlight to hydrogen. Producing H2 gas by electrolysis driven by PV would be more efficient.
It's a common nuclear talking point that solar is impractical because of efficiency. This is a bogus argument, since comparing efficiency of schemes that use different inputs is comparing apples and oranges. Sunlight is cheap and abundant and can be wasted without intolerable pain.
Nor does nuclear at the scale necessary to power the world. Today's commercial reactors can't do it; breeding is needed. This would mean scaling up breeder reactors by roughly a factor of 1000. This is actually a larger scaleup than would be needed for storage, I believe.
What, you're allowing nuclear to scale up, but not storage? Very high double standards you all have in Nuclearstan.
Breeder reactors are such an overlooked technology. Only Russia and India are seriously pursuing them. The thing about breeder reactors is they can get rid of the nuclear waste problem and use 100x the energy of the input fuel vs conventional reactors. It's much more technically complicated, and the biggest ones are only 800 megawatts right now, but they could conceivably go much larger.
No breeder program has ever closed the fuel cycle, and the "closed" cycle doesn't even aspire to get rid of the fertile isotopes which will just be more high level waste.
What reprocessing does do though is let out all the Kr, Cs, Tc, T and so on that was safely contained in your spent fuel bundle. Much of which is just vented or dumped in the ocean.
As solar becomes cheaper and cheaper, low efficiencies may still be worth it. We're never going to power a 747 on solar, but if the energy in the fuel comes from the sun, even if 90% of that is "wasted," it's still greener.
Doing the process with standard technology will always be a PITA, partially because catalytic agents tend to not just be expensive but primarily sourced from questionable or enemy nations.
I think the eventual answer will be in genetically engineered microbes or plants, if only because it is easier to scale up vats with microbes and nature already has figured out synthesis paths for ages.
Terraform industries used to claim that their natural gas would be cheaper than local natural gas in 2027. They now say that the IRA has moved that timeline up to 2024.
If someone asked me for a current cost calculation for a large-scale facility producing methane or methanol, off the top of my head I imagine it's still 5-10X as expensive as mined fossil fuels are. Economies of scale might bring that down to parity fairly soon, however.
Unfortunately it consumes a tree, which takes a while to replace. Better to be able to build a facility that can produce what you need on a continuous basis.
Interestingly I had to reword my comment (plant->facility and evergreen-> continuous) to avoid looking like I was trying to pun. Natural metaphors are a deep part of our thinking about the world.
>Better to be able to build a facility that can produce what you need on a continuous basis.
Yeah see that's the wrong thinking of us humans. The best systems are those established by nature. Remove and bind CO2...yes trees and algae and shellfish have some million years of training in that.
Lets see this at scale..you need so many solar-panels that you already wasted mw's of energy, just to waste that energy for a process nature is already much better.
It just to make stocks and money...not to safe the climate, well maybe it's meant to make vodka in space-stations, then i am ok with it.
Or wood gas. At the end of WW2 there were about 500,000 vehicles with wood gas generators in use in Germany to make up for the lack of other fuels.[1] But under today's conditions, this possibility does not seem to make economic sense.
The most interesting I ever ran across was people doing artificial photosynthesis to produce H2 and combustable oil, e.g. Nate Lewis' group at Cal Tech. Same problem: contemporary economics.
I'm glad people are still working on these problems.