Friday, May 23, 2008

Hot About Gas Prices

Gas officially passed the $4 mark in California yesterday and the Memorial Day holiday weekend has given the statewide chorus of aggrieved motorists a platform from which to shout about it.

But lost in the outrage is a forthcoming "Mother Nature Tax" on gas that experts predict will be good for an eight cent per gallon spike in prices. It all has to do with rising temperatures and "hot gas".

Elizabeth Douglass breaks down the hot gas phenomenon in the Los Angeles Times today. The net-net is this: when temperatures rise, the gas you pump into your car gets warmer. Gasoline expands when it gets warmer, netting you less energy per gallon.

According to the Times:

"The science behind the hot-fuel controversy isn't in dispute. The U.S. government defines a gallon of gas this way: At 60 degrees, a gallon is 231 cubic inches. But when fuel is warmer than 60 degrees, the liquid expands, yielding less energy per gallon. When it's colder, the fuel contracts. Gasoline expands or contracts 1% for every 15-degree change in the fuel's temperature. Diesel volumes change 0.6% per 15-degree change."

It would seem logical that the way to combat this problem is to put temperature controls on gas pumps, but that would eliminate the seasonal prfit surge gas stations enjoy so, guess what? No temperature controls on gas pumps.

Douglass notes:

"There is nothing illegal about the practice. It's been allowed for decades by measurement regulators who assumed that retail fuel temperatures stayed close to the government standard most of the time, and that any losses from hot fuel in the summertime would be offset by gains in the winter."