Gas Prices

[Uncwilly]

Originally Posted by Dr Sardonicus

Individual states have their own motor fuel taxes. The highest gas tax is in Pennsylvania, 58.6 cents per gallon. Next highest is California, 53.3 cents per gallon. The lowest is Alaska, 8.95 cents per gallon.

Part of the reason California has that rate is that they are factoring in the carbon footprint of gasoline. If that helps point people to hybrids or CNG or fuel cells or electric, then it is doing part of its job.

[kriesel]

Originally Posted by Dr Sardonicus

Other factors, which vary by state, include special requirements on gasoline blends or the sulfur content of diesel, and the cost of getting the fuel to the pumps. Shipping costs depend partly on where the gasoline is refined, and how close it can be brought to where it's needed by pipeline. (It has to be trucked the rest of the way.)

That would be so in an efficient honest market with stable prices. I think we may not have those. Often in the Madison WI area, including currently, the price is highest nearest the local pipeline terminal/tank farm, located in McFarland WI. I've seen >10% pump price variations within 20 miles. There are also indications that prices correlate positively locally with neighborhood income levels. With tools like Madisongasprices.com one can take advantage of the spread while in the course of normal errand drives, or setting out on or returning from longer trips. Sometimes the better prices are along or near the far end of a longer trip feasible with a single vehicle fill (~150 miles 1 way). One can economically haul fuel quite a distance at low differential cost, if the trip is being made anyway, since it only modestly increments rolling friction and has virtually no effect on aerodynamic drag. I would not usually carry more fuel in cans in a vehicle than the volume of the vehicle's tank, and would arrange them with other cargo or netting so that they're unable to tip over with normal or emergency evasive accelerations applied, for safety and to avoid spillage loss. https://en.wikipedia.org/wiki/Rollin...umatic_tires_3
The additional distance that is economical to drive solely to purchase cheaper gas is typically single digit 1-way miles or km, using IRS cost/mile figures, in a hybrid or pickup.

One can also time the market a bit, by filling all available legal containers early during increasing-price periods and emptying them during declining periods. Although attention to seasonal blend and aging is advisable; rotate the stock. Gasoline purchased 2 months ago at average locally $3.65/USgallon has appreciated to $4.86 (replacement cost). That's an annual rate of return on investment of ~200.% annually (simple, not compounded).

[xilman]

Originally Posted by Dr Sardonicus

Motor fuel used for farming is exempt from federal motor fuel taxes, and AFAIK from state motor fuel taxes as well. Diesel fuel for off-road use is dyed red to indicate its tax-free status. If you're caught using dyed diesel on the road, you're in trouble.

Individual states have their own motor fuel taxes. The highest gas tax is in Pennsylvania, 58.6 cents per gallon. Next highest is California, 53.3 cents per gallon. The lowest is Alaska, 8.95 cents per gallon.

Much the same variation in tax rates (though not the absolute values) occurs in Europe. AFAIK, the Canaries are the European equivalent of Alaska. The UK is towards the high end but is not the highest.

Red diesel, with the same properties, is sold in the UK.

[tServo]

What infuriates me are interviews you see on local AND national TV in which a reporter shoves a mic into someone's face at a gas station when they're refueling their gas guzzling beast vehicle and ask them "Are gas prices high?" Sheesh !

[paulunderwood]

Are all petrols (gas) the same in terms of miles per gallon? Some are 10%, some 20% ethenol?? (I'm no chemist.) Given the same car and conditions, do the petrol mixtures get the same miles per gallon? Is there stuff substituted into diesel too?

[kriesel]

Originally Posted by paulunderwood

Are all petrols (gas) the same in terms of miles per gallon? Some are 10%, some 20% ethenol?? (I'm no chemist.) Given the same car and conditions, do the petrol mixtures get the same miles per gallon? Is there stuff substituted into diesel too?

Comparing E85 to E10 on a FlexFuel pickup, and the same route and load, E85 needs to be below ~75% of the E10 price /gallon to be a better bargain financially (lower fuel cost per distance traveled). I think the included taxes/gallon are the same. So by diverting more food energy to transportation, using E85, the governments' revenue is increased by ~33% for the same distance traveled with the same vehicle. That may justify some offsetting tax credits. https://www.eia.gov/todayinenergy/detail.php?id=18551 https://mechanicbase.com/cars/e85-vs...ne-comparison/

The amount of biodiesel that can be substituted entirely for or blended into fossil diesel is limited by its gelling at low temperatures. I didn't know how it compares for energy content. But the table here does. B100/B0 ~91%; E100/E0 ~67%. Linearly extrapolating E0 and E100 to E10 yields 1.05 gallons required for equal energy to 1 of E0; E85 in the table is 1.39 gallons; 1.39/1.05 ~1.323, 1/1.323 ~0.756, pretty close to what I observed in use.
Considering E85 is moot though for small engines or vehicles which are not designed to be compatible with it. E85 can cause damage to elastomers and corrosion to metal parts, requiring expensive repairs.

[rogue]

Originally Posted by kriesel

Considering E85 is moot though for small engines or vehicles which are not designed to be compatible with it. E85 can cause damage to elastomers and corrosion to metal parts, requiring expensive repairs.

I learned that the hard way. I had to replace the oxygen sensor (?) in a car when I did that. I think I got off cheap.

[Dr Sardonicus]

Originally Posted by paulunderwood

Are all petrols (gas) the same in terms of miles per gallon? Some are 10%, some 20% ethenol?? (I'm no chemist.)

No. Burning a gallom of ethanol produces less energy than burning a gallon of gasoline. Only about 2/3 the energy IIRC. So the more ethanol in the mixture, the lower your mileage will be.

The octane rating may also affect your mileage. The rule of thumb I learned was, use the lowest octane that prevents knocking.

There other considerations. Ethanol attracts moisture. You can get a nasty witches' brew of stuff in your fuel system. You could have corrosion. I don't know whether gaskets or seals can suffer. Some fuel systems are designed to deal with anything from pure gas to pure ethanol, but not all.

I'm not sure whether ethanol mixed with gasoline promotes crud being deposited on fuel injectors.

Many lawnmowers do not take anything more than E10. This may cause trouble if many gas stations start selling E15.

You should not put any alcohol in a 2-cycle engine. They take a "premix" of gasoline and 2-cycle oil. As an example of offering convenience being a license to print money, Stihl offers premix made with ethanol-free gasoline, and of course others are now offering the same type product. Last year, the stuff was over $7 per quart.

Luckily, I found a gas station nearby that sells 91 octane, ethanol-free gasoline. I put an additive in my gas can and go fill it up for my lawn mower and weed whacker. I make my own premix with that gas. Last time I bought it, it was $5.69 a gallon, compared with $5.09 for 87 octane E10 at the time. Last year and the year before, the price difference had been much greater.

The site puregas.org lists gas stations selling ethanol-free gas in the US and Canada.

[kruoli]

Originally Posted by Dr Sardonicus

Many lawnmowers do not take anything more than E10. This may cause trouble if many gas stations start selling E15.

We have a lawnmower, around 30 years old, with a Briggs & Stratton engine. It will take pure ethanol, but it will also take a mix of 25 % diesel and 75 % used 15W-30. But of course I know that this is not common and unhealthy for the engine. I only know this because the engine began to lag and a repair was out of question, so we tried different fuels to see what might extend the life time of the engine the most. Beside a manual overhaul it seemed like it ran best with 90 % E5/E10 (no remarkable difference here) and 10 % 5W-40, from the things we tested.

[Dr Sardonicus]

Originally Posted by kruoli

We have a lawnmower, around 30 years old, with a Briggs & Stratton engine. It will take pure ethanol, but it will also take a mix of 25 % diesel and 75 % used 15W-30. But of course I know that this is not common and unhealthy for the engine. I only know this because the engine began to lag and a repair was out of question, so we tried different fuels to see what might extend the life time of the engine the most. Beside a manual overhaul it seemed like it ran best with 90 % E5/E10 (no remarkable difference here) and 10 % 5W-40, from the things we tested.

Keeping a lawnmower in service for 30 years is commendable. The rule of thumb nowadays is that if you take care of your mower it will last 10 years. If you don't, it will last 5 years.

It is generally assumed that a lawnmower's engine will outlast the rest of the mower - especially if it's a Briggs & Stratton engine. They are often described as practically indestructible. I have seen it said that they would run if you put whale oil in the crankcase. Or was that the gas tank?

But after 30 years - I am reminded of George Burns saying WRT his lead role in the Oh, God! movies, ""Why shouldn't I play God? Anything I do at my age is a miracle."

The fact that adding motor oil to the fuel seems to help may be diagnostic. I'm not a mechanic.

My mower has a Briggs & Stratton engine, and it says not to use anything over E10. I give it treated ethanol-free gas.

Of all the basic maintenance things I do on my mower, the ones I think are most important are to (1) check the oil before each use, and (2) scrape out the grass clippings from under the mowing deck after each use.

Running the engine with insufficient oil could destroy the engine. Stuck-on grass clippings not only interfere with air circulation, but they also retain a lot of moisture. Moisture promotes rust. Corrosion is the great enemy of metal.

Mowers nowadays are equipped with ports on the deck that allow you to attach a hose and run the mower to (try to) wash out the stuck clippings. But that method doesn't work very well. And, of course, it leaves the underside of the deck wet.

[Uncwilly]

Originally Posted by Dr Sardonicus

The rule of thumb nowadays is that if you take care of your mower it will last 10 years.

The rule of thumb now-a-days is that you should buy an electric unless you have a large plot. It should last much more than 10 years and require less maintenance. You may need to change out a battery after a few.