For the uninitiated, from June 1 - Sept 15, the RVP limit is set to 9.0 to reduce evaporation of fuel from cars and storage and transfer equipment during the summer months. When gasoline evaporates, it contributes to smog. The PSI for E10 increases by 1 during the summer months but Congress-imposed an RVP waiver for E10 years ago.

In the case of E15, the Department of Energy's National Renewable Energy Laboratory (NREL) says the RVP for E15 is indistinguishable from E10. However, in absence of a waiver from Congress or the EPA (which is currently the case), E15 can't be sold during the RVP season.

Since the RVP ban doesn't extend to flex fuels, most retailers (who have obviously made substantial investments to even offer E15 in the first place) are left with no choice but to label E15 as a flex fuel to avoid substantial losses. In 2016, E15 sales fell by 50 percent during the RVP season. This year, with 148 stations currently offering E15 in Minnesota, the expected volume drop during the RVP season may be more significant. 

There have been some movements in Congress this year to bring RVP parity but all of those efforts have failed. The EPA on the other hand could fix this problem. As pointed above, the RVP for E10 and E15 are indistinguishable. In other words, this RVP ban on E15 defies all laws of logic.

In fact, ethanol has a lower RVP than gasoline. The PSI in E10 only increases when ethanol and gasoline are blended and the RVP of the gasoline blendstock used is high. If a gasoline blendstock with a lower PSI is used (such as in reformulated gasoline), E15's RVP becomes a non-issue but that's not always readily available. You can read more here.

So why isn't the EPA doing anything about it? There's a new administration and yet there's still this mind-numbingly stupid RVP ban on E15.

Perhaps that's not surprising since the new EPA administrator (who has plenty of anti-ethanol rhetoric on his resume) is far more interested in championing the interests of the coal and fossil fuel industries than fixing this issue. A cynical person might even say it is actually in the interest of the fossil fuel industry to keep the RVP ban on E15.

It certainly doesn't seem like there's an ethanol champion in the White House.