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Motorists Sue Over 'Hot' Fuel

i_like_spam (874080) writes | about 7 years ago

The Courts 5

i_like_spam (874080) writes "Motorists in 13 states have filed lawsuits against big oil companies and gas retailers alleging unfair pricing practices related to fuel-pumping temperatures. From an industry standard developed in the 1920's, the price for a gallon of gasoline is based on the density of the fuel at a temperature of 60 degress F. A gallon of gas at higher temperatures is less dense, and therefore contains less energy. The lawsuits claim additional costs of 3 to 9 cents per gallon without temperature adjustments. The fuel industry claims that the costs of installing temerature-adjustment sensors on every pump would be prohibitively high. These sensors are already installed in Canada, however, where the colder temperatures favor consumers."

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5 comments

Coefficient of thermal expansion (1)

mdsolar (1045926) | about 7 years ago | (#19756297)

Here's a link if you want to check the math in the article: http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Th ermal/ThermExpan.html [wwu.edu] . For a 20 C change in temperature I get about a 2% change in volume so at $3/gal this comes in close to 6 cents.
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Easy solar power: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

Re:Coefficient of thermal expansion (1)

iamlucky13 (795185) | about 7 years ago | (#19757183)

I see three obvious issues here:

1.) It's going to cost money to regulate the temperature of the fuel. You'll get different amounts of fuel depending on the temperature, but it averages out on the long-term. If you force regulation of the temperature of the fuel, you've raised the cost of dispensing it regardless of the temperature.

2.) The price you pay is related to the price the stations pay plus their operating costs. As long as all stations in a local market experience similar temperature/volume changes, competition keeps the long-term profits roughly consistent.

3.) Temperature is one of many factors affecting the actual mass of fuel you get. How far does one want to take this? The meters on the pumps have accuracy limits too. There's some fuel left in the hose when you shut the pump off. Some fuel is spilled. Some evaporates (which is why it's best not to fill up in the heat of the day). Some fuel is probably annihilated by those pesky, rare collisions with neutrinos. Etc. It's the same for any product. A 5 pound bag of potatoes is not exactly 5 pounds.

I'd give this credence if they thought stations were deliberately heating their fuel to increase the volume, but otherwise this is a waste of resources with a net cost to consumers, and a drain on the legal system. I rather suspect the aforementioned stations in Canada monitor temperature to prevent the fuel from gelling in cold temperatures, not to improve the mass-accuracy of their volume-based meters.

Re:Coefficient of thermal expansion (1)

mdsolar (1045926) | about 7 years ago | (#19760773)

I don't think the temperature is regulated, rather the pumping is compensated delivering more volume to make up a regulation gallon when the temperature is higher. Clearly, our current pattern favors the seller since prices are higher when temperatures are higher, but I would say that the energy dilution from including 10% ethanol in the summer is an even bigger factor.

But, I'd agree, regulating this seems as though it would be a hassle. Better to get off gasoline all together.
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Recent congressional testimony (1)

i_like_spam (874080) | about 7 years ago | (#19760375)

Recent congressional testimony on this topic: "Hot Fuels - The Impact on Commercial Transactions of the Thermal Expansion of Gasoline" [nist.gov]

A couple of interesting tidbits from the testimony:

In some states, compensating for the temperature of refined petroleum products being sold has taken place at the wholesale level -- but not at the retail gas pump (diesel included) or for deliveries of home heating fuel. Some states prohibit temperature compensation at retail and some states prohibit temperature compensation anywhere in the petroleum distribution chain. Most states require temperature compensation for certain products, such as for liquefied petroleum gas (LPG) sales, or propane for home heating, but not necessarily for other products.

A review of the application of temperature compensation to petroleum volume data showing average fuel storage tank temperatures in the U.S. and possible effect on petroleum measurement. The data on storage tank temperatures, collected by a manufacturer of tank monitoring equipment, over a two year period indicated that the average temperature of product in below ground tanks across the U.S. was 64.7 degrees Fahrenheit.

storage tank temps (1)

fred fleenblat (463628) | about 7 years ago | (#19761911)

Also the underground storage tanks probably equalize the temperature quite a bit. 10 feet down, the ground is nearly the same temperature all year.
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