Peter wrote:
It is probably one of the specially blended fuels available in specific markets – Sweden? I thought they have 96UL or some such.
Hjelmco sells 91/96UL in Sweden. Wikipedia states that UL94 is 100LL without TEL. Like you, I thought that was UL91. Oddly enough, UL91 is not mentioned on the Wikipedia AVGAS page. Possibly UL91 and UL94 is the same fuel but with different ways of measuring the octane rating?
Added: I’ve looked at Lycomings “Specified Fuels” Service Instruction and exactly the same engines run – or not – on UL91 and UL94 so that also suggests they are really the same fuel. (In contrast with Hjelmco 91/96UL which does not work on exactly the same engines as UL91.)
UL91 is a strange fuel. According to the ratings it should have higher octane rating the mogas 95. In practice it has much lower.
There is a new thread initiated by George Braly in Beechtalk about G100UL now getting more and more approvals.
It will be available to the US GA community eventually.
https://www.beechtalk.com/forums/viewtopic.php?f=37&t=204773
FAA approval: https://gami.com/g100ul/G100UL_Oshkosh_Press_Release.pdf
My question is, how is this going to work over here, in the UK and Europe ? Does anyone have any ideas ?
I don‘t know. Assuming for a second that all engines will eventually be FAA-approved for 100UL later this year, it will still take years for anything to really change here. First, some EASA approval will be needed. Then, I guess that some companies like Warter will start producing it. And then a few isolated airfields will start offering it instead of 100LL. And if the price is half-reasonable, say only 0.5€ more than 100LL, then it might replace 100LL over the next few years. I don‘t think 100LL will really be banned in Europe so soon, if at all.
Hmmm.. isn’t it true that EU refineries at some point in the next year or so either have to try and stop TEL from being banned in Europe from 2024 onwards, or they need another alternative. Otherwise it will be banned, no ? If it must not be imported as a substance, other than as an additive to imported fuel, there won’t be anyone left producing Avgas 100LL at all. Am I right ?
EuroFlyer wrote:
If it must not be imported as a substance, other than as an additive to imported fuel, there won’t be anyone left producing Avgas 100LL at all. Am I right ?
You’re right that if this proposal goes through then no 100LL can be manufactured in the EU – it will all have to be imported.
Is there currently a process or anything official going on in that regard, at all ?
@George_Braly joined EuroGA years ago but is not responding to notifications. If we wants to get 100UL awareness over here, he really ought to 
US forums are really “distant” over here…
EU refineries at some point in the next year or so either have to try and stop TEL from being banned in Europe from 2024 onwards, or they need another alternative. Otherwise it will be banned, no ? If it must not be imported as a substance, other than as an additive to imported fuel, there won’t be anyone left producing Avgas 100LL at all. Am I right ?
They can buy it from the UK There would be huge pressure to stop that, of course 
It would have to be sold via the Peoples’ Republic of Upper Volta.
The end of AVGAS is planned for 2030
Source
The big step to open the floodgates will be G00UL approval for all engines, including all the large bore engines requiring 100LL. Once that happens, the US can be expected to migrate from 100LL to G100UL rather fast I would think.
They can be mixed, can’t they? And can’t the same infrastructure be used for delivery of both? If that is true, then it is simply a question of ramping up G100L production until it can meet the 100LL demand and then 100LL production can be shut down. Or is that idea too simplistic?
