Looks like you've been going down a similar path as me. Unfortunately, liquid fuels from pure electricity is extremely energy inefficient. For example, the fischer tropsch process will consume the hydrogen that you've split with precious electricity, and only half of that will make its way into the fuel, the other half of ends up converting back into water. And that is before you figure out how to get CO2 in concentrations high enough to be cost effective.

You might want to check out plasma reforming. It's the path I'm currently on, although targeted for a different end product.

https://drexel.edu/nyheiminstitute/researchlabs/plasma-energ...