Renewable fuel, in this case refers to alternate means besides long dead dinosaur bones and plant matter from deep underground.
End product of it is still pretty much same CH solutions so reduction in CO^2 would not be that huge.
yes, it'd be smaller than with crude oil base but still pretty much same once car's engine uses it.
It doesn't really help that due to smaller scale, Renewable fuels, ethanol or otherwise, are still more expensive to manufacture than Oil products.
only exception is pretty much Biogas alternative to Natural gas, since waste disposals get that anyway and either store it and sell or or burn it to get rid of it, decomposing matter releases quite lot of it. (but not enough to allow people to fully switch NG to BG
The current obsession with full EV is unsustainable, to work, fully EV vehicles need quite big batteries to go farther than intra-city transit, for which they are good.
for longer distances, you'd need super-chargers and such which cost to implement and still means you have to plan odd 800 to 1000km/mile trip carefully and/or if you MUST stop for hour or two to charge up.
another problem are the greenified Hybrids that have 480hp gas engine and 400hp Electric in it to get tax deductions.
better solution would be to basically BAN all cars of over 200hp, you do not honestly need more than that except maybe in german autobahns if even there.
also you'd get lot better fuel economy by putting small 10 to 20hp gas engine in each car, whose sole job is to charge the small 5 to 10kWh battery car has, this gives a LOT better fuel efficiency since you can optimize gas engine to run at optimal RPM to charge the car, while Electric motor runs the car forward.
and yes, that engine would be big enough to keep you driving steady 80 to 100km/h while still charging the batteries in excess of what you use to keep that steady pace. Giving car best of both worlds, good fuel economy, fast refilling and lower Co^2 emissions.