Maybe going off topic a little.
But here in Sweden much of the standard pump fuels are 'diluted' with other fuels to lower CO2 and in some cases increase economy. There are specialist fuel suppliers, but for general use it might not really be worthwhile as it is often mixed in.
Preem who are leading this have the following for regular customers:
Petrol - 90 % petrol with 5 % ethanol and 5 % bio ethanol.
Diesel - 70 % diesel and 23 % veg oil (from the wood industry) and 7 % RME (rape oil)
They have also just released a new diesel that is 50 % diesel, 7 % RME and 43 % veg oil.
The bio gas (CNG I think it is called) is 50 % bio gas and 50 % natural gas.
Company customers have the ability at most stations to purchase 100 % diesel and also 100% bio diesel.
New fuels take time to come into favour, VAG (VW, Auldi, Skoda) vehicles do not like bio diesel, at the previous company I worked at we had diesel fuel that was 40 % bio diesel and the two Crafters that we had needed alot of service on the fuel system and both had the fuel systems replaced between the tank and the engine.
Many of the city taxis are Bio CNG with the basis of the fuel being collected household food waste.