Almost every station I go to has ethanol (up to 10%) added to gas. For a long time I had the option in my area to buy non ethanol gas but now it’s harder to find.
If a gallon of ethanol gets less mileage per volume than gasoline, then how is it better for the environment if I have to fill that much sooner on gas because the ethanol component lowers my tank range?
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Not saying mandatory ethanol blend wall is a good thing, but use less gasoline but less mpg tells us nothing.
First question would be degree of each impact. We’d have to do the math of how much it reduces mpg vs. how much gasoline it displaces. On this level, because ethanol has energy content you most certainly will burn less gasoline regardless of how often you have to fill up.
But if the implied question is does it put less carbon into the atmosphere, that’s also an it depends. At a super direct analysis I don’t think there’s any significant difference in miles you move your car vs. how many pounds of CO2 go out your tail pipe. That analysis is basically a wash (talking broad strokes here) of burn more ethanol at a lower energy content, resulting in roughly equal CO2.
The second order analysis (and the one where ethanol would have theoretical climate benefits) is that you make ethanol, by pulling CO2 out of the atmosphere into corn, corn to ethanol, ethanol back to road miles+CO2. Any road miles that are fueled by this process instead of gasoline means a portion of the existing stock of crude oil stays in the ground. Crude oil is essentially million year old “corn” that broke down in a way that sequesters the carbon in a way that it doesn’t come out unless we pull it out. The present day corn to fuel to CO2 fo corn cycle is theoretically (emphasis on theoretically) carbon neutral. So compared to burning the carbon that was sequestered under ground via crude oil it means less carbon to the atmosphere.
The third order analysis is that growing corn in the present day, converting it to ethanol to burn in cars does take energy. Possibly more energy than it takes to get crude oil out of the ground and refine it to gasoline. Whether that extra energy makes it “not worth it” from a carbon balance standpoint is a very complicated calculation and can probably go either way depending on the specifics.
Then you have to broaden to “well that carbon balance question has this impact per the above calculation, however what about all other relevant questions”. Impact on food prices? Chemical pollution of waterways? Land use? Increased driving and other fuel use behavior because people feel like they did something to offset the problem. All of those questions need to be evaluated and their pros and cons need to be weighed as a matter of public policy.
My general point is that just because there’s a tradeoff (less gasoline but lower mpg), it doesn’t necessarily mean anything conclusive. But if you do the math and analyze a variety of competing priorities you may be able to come to the conclusion
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That ethanol subsidies and blend walls are BS 🙂
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