Court strikes Trump EPA rule for full-year 15% ethanol sales
Source: Omaha World Herald-AP
By DAVID PITT
DES MOINES — A federal appeals court on Friday threw out a Trump-era Environmental Protection Agency rule change that allowed for the sale of a 15% ethanol gasoline blend in the summer months.
The decision deals a significant blow to the ethanol industry and corn farmers who grow the crop from which the fuel additive is made. They had anticipated increased ethanol demand through year-round sales of the higher blend.
Most gasoline sold in the U.S. today is blended with 10% ethanol. Corn farmers and ethanol refiners have pushed for the government to allow the widespread sale of a 15% ethanol blend.
The Trump administration made the change to fulfill a campaign promise to Midwest farmers. The EPA under President Donald Trump announced the change in May 2019, ending a summer ban on the E15 blend. Provisions of the Clean Air Act have prohibited the sale of certain fuels with a higher volatility from June 1 through Sept. 15 to limit smog. Congress has allowed 10% ethanol, and the EPA in its 2019 ruling revised the interpretation of the exemption to federal law to include the 15% ethanol blend.
Most gasoline sold in the U.S. today is blended with 10% ethanol. Corn farmers and ethanol refiners have pushed for the government to allow the widespread sale of a 15% ethanol blend.
REBECCA S. GRATZ, THE WORLD-HERALD
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Where does water come into the equation? There's no water in ethanol. The ethanol molecule is C2H5OH.
For those who do not know, read what's on the picture. The amount of ethanol added to fuel grades is UP TO E10 or E15. Why is that, you may ask? Because fuel octane grades (87, 89, 91, 93 octane) will have varying amounts of some percentage of ethanol lower than 10% or 15%, respectively.
Ethanol is an octane modifier and fuel oxygenator. It is 110-112 octane by itself. The ethanol molecule has one oxygen atom in it. Gasoline by itself, aka pure gasoline, aka ethanol-free gasoline does not have an oxygen atom in it and is refined at a relatively poor or low octane level, usually 83 to 85 octane. One reason ethanol is added to pure gasoline is to boost its octane, as a cheap form of octane booster that our high-compression IC engines can use.
Typically, at any randomly selected pump, regular 87 octane will have the lowest percentage of ethanol (usually 3 - 5 %, not 10%) and 91 will have the most ethanol (usually at or under 7%). The other reason to add ethanol is to bring oxygen to the Air-to-Fuel ratio party, which by definition results in cleaner exhaust emissions.
Pure gasoline is dirty, when burned, because its molecule has no oxygen atom. It's also expensive to refine in high octane grades natively, often termed by the industry as "sub-octane" gasoline. Which is partially why over the years tetraethyl lead, MTBE, ETBE and ethanol octane boosters have been added. Tetraethyl lead is toxic to plants and animals at any level, a 1/4 cup of it on your skin will kill you. MTBE and ETBE are also toxic, which is why all three have been banned for use in most countries. Ethanol is not toxic and won't contaminate ground water, as its molecule is something that breaks down naturally or can be diluted.
Fuel is typically trucked to the retailer in either of two tanks, 87 octane and 91/93 octane. It is then blended in ratios, at the pump dispenser, proportional to the minimum octane rating selected, if the selection was in between 87 and 91/93. You'll often see 89 and 90 as an option. The retailer does not have a tank for these grades. They are a nozzle blend, a mixture of fuel coming from the retailer's two tanks of 87 and 91/93. This is why if you have E0 (pure-gas/ethanol free) available to you, it is dispensed from a separate hose nozzle, coming from it's own separate tank and is ONLY available in one octane rating.
I have a few older internal combustion engines designed for use with E10 or up to 10% ethanol. And because E10 provides performance advantages and versatility for where I live, I use E10 exclusively, not E0. 
E10 is up to 10% ethanol. Retailers cannot legally dispense E15 or amounts of ethanol greater than 10% from a dispenser rated at up to 10%. If the dispenser shows E10, then the fuel in the tanks below are up to 10% ethanol, not up to 15% ethanol!!! 
Please elaborate on the evidence to back up your claim.
And your reply makes it sound like you didn't even read what I wrote beyond the title of my post.
Claim: you don't know how much ethanol is in the fuel.
A: you can test it, but it's going to be BELOW what is claimed. E10 is up to 10%.
Claim: Ethanol has up to 20% less energy. Therefore you will get 20% worse gas mileage from that same vehicle
A: that is 100% false by definition. 
The energy lost usually equates to about 4% for an EFI vehicle. Scotty Kilmer simply made some over generalizations. But if he did a little more homework would agree, those two comments are misleading.
Let me explain and you'll see how this is true. Depending on who is saying this claim, they'll often use a ratio of 20% - 35% for ethanol being less efficient than gasoline. But no matter what ratio, it doesn't matter. The claim of 20% worse mileage, or whatever, will turn out to be false. And for a carburetted vehicle that's only run E10, it's efficiency will prove to be about 4% better than when filled with 100% ethanol-free.
First, the makeup of pump gas is up to 10% ethanol. That means the fuel is no less than 90% gasoline and up to 10% ethanol. Let's assume that E10 pump fuel is 10% ethanol, which it will rarely be, it's often up to 7%. If 10% is ethanol, then 90% of the fuel will produce 100% of the energy it is capable of up to its 90% capacity. So that's 90% energy right there. To be the devil's advocate, let's say ethanol has 35% less energy than gasoline, that means the 65% has 100% the energy of gasoline. Therefore 65% of the 10% ethanol makeup has 100% the energy of gasoline, which boost our energy number up to 96.5%, which only leaves 3.5% of the fuel makeup that's less efficient. Again that's at a ratio of 10% ethanol. How does 3.5% of the fuel makeup result in 20% worse mileage in an EFI vehicle? The EFI vehicle has a computer and O2 sensor that work in a closed loop to take full advantage of both E0 gasoline and E10 ethanol!!! No, it's closer to 4% for EFI vehicles.
Following along . Carburetors are fixed fuel metering devices, unlike fuel metering systems like fuel injection. Carburetors use jets, brass objects with holes in them. Gasoline and ethanol basically flow at the same rate through jets. Therefore, if you put E0 in a vehicle that's only run E10, you will take away the oxygen that's built into E10. The fuel mixture will be richer and the engine will burn MORE fuel to go a shorter distance, simply because the AFR will not be stoich, where it is most efficient. To its logical extreme, adding 100% E0 to a carburetted motor that's only run 100% E10 fuel will result in about a 4% loss in fuel mileage.
