How accurate is what? The availability of fuel without oxygenates or the energy density?
The requirement for oxygenated fuel is highly local. A few states have mandates that all fuel sold must be reformulated. Some states have mandates that a certain percentage of fuel sold within the state be RFG but not all. Some states have no requirements on a statewide level but local counties have their own rules.
Here is southeastern Wisconsin we are located in an EPA non-attainment area so for all practical purposes RFG is the only fuel you can buy. Even though the actual non-attainment area is isolated to the Milwaukee area (in terms of air quality), the mandate is extended to surrounding counties so that Milwaukee residents cannot easily travel to neighboring counties for non-oxygenated fuel. But if you travel outside the area you can buy gasoline in all grades without ethanol.
However, there are areas in Wisconsin that have local/county mandates so you can find pockets where you cannot buy non-oxygenated fuel. In the areas where non-RFG gasoline is available the most commonly available octane rating is 91 and is often called "recreational fuel" (and is sold at the same pump as all the other grades). But some stations do offer 87 octane non-oxygenated fuel. Here in the non-attainment counties our premium grade is 93 octane and contains up to 10% ethanol.
http://www.pure-gas.org/ is a good website to show just how local and fractured the availability is nationwide.
My comments weren't really geared towards availability but towards energy density as related to octane rating.
Originally Posted By: southernjeeper
Originally Posted By: kschachn
The energy content of gasoline is irrespective of the octane rating - assuming it is all gasoline. If it is a blend of gasoline and ethanol then that does not apply. Some regions/stations sell premium that is E0 instead of E10, that can make a difference.
How accurate is that? I thought premium fuel had the same 10% of ethanol as stated on pumps as the lower 87 and 89 grade?