(A) - Why does premium cost so much more than regular? There is just as much energy in a gallon of regular as there is in a gallon of premium. Where I live the price differential is upwards of 25%.
(B) Because ethanol and water DO mix, and because gas with ethanol degrades, certain items (lawn mower, outboard motor) recommend gasoline without ethanol. My local hardware store wants $23 for one gallon. There is a station about 12 miles from my house that charges $15 per gallon for more than one gallon. In addition to my “why so expensive” question, do these gasolines have the road tax included?
(C) The only time I’ve seen a gas station with E85 (85% ethanol), the price was about 15% less than regular gas, yet E85 has only 72% of the energy content of the 10%-ethanol that I am forced to buy. In other words, on a per mile basis, E85 is 18% more. Ethanol is a boondoggle anyway. On a per joule basis, it costs substantially more to produce than ROTM gasoline.
Because the gas station corporations have determined that is the price that maximizes their profit.
Does the gas station warn you it would be illegal to put this gas in your car? I’m guessing no, so the price includes road tax.
That is not a question. But the answer to the question I think you intend is that even if we removed all the political considerations around adding ethanol to gas, the core pricing mechanism would still be supply and demand. If customers were hard-nosed “bucks per joule” maximizers, prices would more closely correlate with energy content.
Premium gasoline (usually 91 RON or higher) costs more than regular (85 RON to 87 RON) because it requires additional fractionation stages to eliminate the lower octane consitutants. Although the chemical energy content of ‘premium’ gasoline is actually slightly lower than ‘regular’, a higher compression engine is able to extract more power (and under certain regimes greater efficiency) due to the higher compression it can be run at. If your car does not specifically require higher octane fuel there is no benefit to using it.
Ethanol is added to gasoline as an oxygenate (oxygen-carrying molecule) specifically to reduce both carbon monoxide and carbon particulate production. Previously methyl tertiary butyl ether (MTBE) was the primary oxygenate and anti-knock agent to replace tetraethyl lead that was used but after several states found mass groundwater contamination its use was restricted or eliminated, and the Energy Policy Act of 2005 shifted gasoline providers to using E10 and E15 mixtures instead. How much this actually helps achieve complete combustion in modern fuel-injected automotive engines is an active question, and the policy seems largely constructed to inflate the demand for corn-derived ethanol, making it essentially a de facto subsidy for corn growers, or a “boondoggle” as you term it.
Depending on your state, the blending may be mandatory for gasoline sold specifically for automotive use (versus ‘camp gas’ and gas sold for mixing), hence the higher costs for ‘pure’ gasoline. The price of automotive gasoline is kept artificially low compared to other chemical fuel and industrial products like ethanol and methanol due to high volume, protectionist policies, and its use as an inducement for other purchases. If you talk to a convenience store owner, they’ll acknowledge that the pump price for gasoline is often near or at cost (including all taxes and fees) and that their profits come from sales of food, beverages, and tobacco. That ethanol-blended fuel costs more pure unit energy is, in part, a reflection of the peculiar economics of the petroleum industry which is driven by the normally inelastic economic and societal need for transportation fuels. See Morgan Downey’s Oil 101 for an enlightening look at the fundamentals of the petroleum industry and why oil is so cheap compared to alternatives.
At one time it used to be a consistent increase of $0.10 from low to mid and another $0.10 from mid to high no matter the price per gallon. This was the way it was for decades. Then all of a sudden it seemed like the high grade shot through the roof, the excuse I heard was that people who had to buy the high test were the one’s willing to pay extra since they paid extra for the high performance motor, and even if some ‘everyday’ cars for the rest of us can benefit from high test it is not required so if they want the performance they have to pay the piper.
It was also ironic because that is the time when they shifted from MBTE to ethanol to oxygenate the gas which was not only cheaper than MBTE, but ethanol was even cheaper than gas the itself and raised the octane rating.
Piecing together parts of Stranger’s and kanicbird’s posts, it sounds like the ethanol content raises the octane rating, and that can improve the efficiency of the engine. So if the energy content of the E-85 is lower, it’s possible that your car may be able to do more useful work (or at least, the fraction of useful work it can do relatively to an equal volume of gasoline could be higher than the strict energy fraction.) A rational fuel purchaser would pay not on a per-joule basis, but a per-mile basis that their vehicle can extract from the fuel. Is that a fair reading?
The Cars.com link @Thudlow_Boink posted made a note that crude coming from newer sources (such as shale oil) have a lower octane rating compared to the more traditional crude sources that are gradually running out. Ethanol is already used to boost octane, but if the gas coming out of the refinery is only 84 to start, then the maximum 10% ethanol can only boost it to standard 87. So to get mid-grade and premium requires more refinement and cost than was necessary in the past.
If your car engine is designed to run on 87 octane, for example, and you fill the tank with 93 octane, your engine won’t run more efficiently.
A low octane gasoline will self-ignite (“preignition”) at a lower temperature than a high octane gasoline. And preignition is not good for an engine.
If preignition (“pinging”) does not occur in your engine with 87 octane, then using a higher octane gas is a waste of money.
If you have a high compression engine, preignition will probably occur with 87 octane, therefore you don’t want to use it; use the lowest octane gasoline (e.g. 91, 93) that does not cause preignition. Better yet, use what the manufacturer recommends.
Now having said that, the above is an oversimplification. Most modern engines can sense preignition using a “knock sensor” and will adjust timing so that preignition doesn’t occur. This means that if you have a high compression engine that calls for 93 octane, and you fill the tank with 87 octane, the engine will sense the preignition and adjust the timing accordingly so it doesn’t ping. But it also means that you will get less performance out of the engine since it’s not operating at its optimal timing.
I’d like to know ‘Why so expensive?’ too. I’ve never heard of a gallon of gas in the U.S. costing $23. (But then, I’ve never heard of a hardware store selling gasoline either. FWIW, my local hardware store charges about half of what the gas station charges for propane.)
I just use regular gas station gas for the lawn mower. I practically empty the tank when I mow the lawns, so there’s nothing in there to degrade. I have a 2-gallon (or 2.5 gallon) plastic gas can. I make sure it’s full after the final mowing of the year so that we have gas for the generator if needed. I put STA-BIL Fuel Stabilizer in it so the fuel stays good.
A couple of dollars isn’t surprising for specialty fuel. (What’s avgas nowadays? Six bucks a gallon?) But the OP states a price seven times what I paid per gallon to fill up my car this morning.
I think I should have clarified that you need an engine capable of taking advantage of the higher octane (a higher compression engine.) I think your last paragraph agrees with that - ie, what I wrote, but assuming a high compression engine. With that clarification, are we in agreement?
They’re referring to “engineered gas” like TruFuel. Here it is for ~$20/110 oz. from Home Depot:
It’s gasoline with different additives and stabilizers, mainly aimed at the small engine market. Other varieties are pre-mixed with oil for 2-cycle engines.
Canned gas (as it’s called around me) is also ethanol free, which is not available in certain areas to buy at the pump. Near me I can only get ethanol free in high test at a certain chain of gas stations (Stewards). But further south starting jsut 10 miles away, it’s not available at all - so if you are in the middle of that ‘zone’ you may have to travel 80 miles to get some if you are in the furthest location.
So unless your travels take you there (and you know the difference), canned gas seems to start looking like a reasonable option especially if your needs for that type of gas are small. And even better if you don’t care to transport gas long distances in your car.
But yes I go to Stewards get the high test and use Sta-bil. Between lawn mower, leaf blower, snow blower, generator, minor spills filling the machines almost all the time mostly do to the EPA’s requirements for vent free gas cans, etc. tend to use 15 to 40 gal/year but during prolonged power outages I will switch to regular gas if I can get it, then run some good stuff when ready to store it again. So at that usage I’m not in the market for $23/gal gas, it’s cheaper to just buy new machines or carburetors.