[smsm42]

This technology already exists.

Step 1: grow trees (or any other plants, in fact)

Step 2: https://en.wikipedia.org/wiki/Wood_gas_generator

Not the most clean or efficient technology, to be sure, but has been around for almost 100 years now (the second part, the first part a bit longer).

[hollerith]

Yeah, I meant figuring out how to do it so efficiently that it becomes preferable to batteries for powering cars. We talk like it is certain that battery-powered cars will win out, but I haven't seen a proof that that is how it must turns out if we learn to create nanomachines that use solar energy to suck carbon from air.

[gibolt]

Unfortunately, physics says battery-powered cars have won.

Using solar to power a process to make a fuel before burning a fuel that at best (way less in reality) uses 2x more energy than just powering an electric motor directly is not sensical.

[hollerith]

And the battery makes the car 1.3 times the weight of a gas-powered car. Making the battery requires much more energy than making a gas tank. The charging infrastructure might prove more expensive than a network of gas stations. Long trips are punctuated by idle periods needed for the battery to charge, so the car's "utilization rate" is lower than a gas-powered car. All I am saying is that it is not 1.00 certain which technology will retain the lowest total cost of ownership as both technologies improve: battery tech is more likely to win, but not certain to win.