Carbon footprint of synthetic fuels and green chemicals - C2V - CO2 to Value In fact - CLIMAX
There are many ongoing research efforts - in academia and in corporate - for green synthesis of fuels and chemicals from CO2 (this one, for example - https://bit.ly/3j5HMgv ).
While these efforts are indeed valuable, what will be of equal value will be a clear indication of the total carbon footprint of the entire synthesis process, and thus the net CO2 emissions saved.
Even though significant energy needs to be used in their production, synthetic fuels (or e-fuels or renewable fuels, the various names they go by) are expected to have a very low carbon footprint because all energy used for their production is expected to come from renewable sources - mainly solar & wind power. But as this interesting article argues, low-carbon could also mean very high cost.
An online search does not seem to provide reliable estimates.
But even where renewable energy sources are used for their production, it does not imply zero carbon, only low carbon as renewable power in itself has a non-zero carbon footprint if an entire life cycle analysis is done.
For these synthetic fuels and chemicals hence, it will be good to have an idea of what their carbon footoprints are.