E85
 

https://petition.parliament.uk/petitions/241024

We have E85 at a few petrol stations here in the northeast US, although it's much more popular in the midwest. While E85 does have higher octane, it has less energy per volume, which means your fuel consumption will increase by about 25%. When you consider that with the price, it's rarely worth it.

Yep, but if your running a big BHP build fuel consumption isnt going to be too much of a concern, you want that far higher knock resistance so you can run much more boost and power, extra fuel is cheaper than an engine rebuild all day long.