E15 Auto Fuel

For the carburated 100hp 912, we have been using (quality) autogas with 27% ethanol content without any issues here in Brazil.

Just avoid the 5% of gas station’s that will have it.

Here in the UK we have recently switched from E5 MOGAS to E10 MOGAS. This is not allowed to be used in aircraft in the UK, only a maximum of E5 is permitted. Some filling stations sell a higher octane E5 MOGAS that is about 6% more expensive but it is still significantly less expensive than AVGAS. I guess that eventually all of the E5 will become unavailable but whether the E10 will be accepted by the relevant authorities remains to be seen.

Less than 2% of gas stations are actually equipped to sell it; it generally cannot be dispensed via ordinary pumps. So if you are buying it, you'll know it.  

The whole thing is just a PR stunt, really.  Let us know if you find any stations where E15 is actually any cheaper.