[ars]

> what's the source for CO2 by the ton?

Coal. Using it like this you avoid all the pollution problems (all the impurities are captured inside the process and not simply emitted).

True you still emit some extra CO2, but that vast majority of the energy content of gasoline does not come from the coal, it's added from the solar power.

So even though you do still emit CO2, as a percentage it's much more minimal.