Consumers Receive Less Gas When Temperatures Rise

Summer driving may cause rising gas prices, but there may be another hidden reason why you're paying more at the pump. High temperatures causes gas to thin, making you pay the same amount for less fuel.

The phenomenon, known as "ghost gas" occurs when the gasoline is hotter than the 60-degree industry standard. The space between the molecules of the gas expands, making it volumetrically larger, but still with the same embodied energy.

When the gas is pumped, it is measured by volume, causing the consumer to get charged for more gas than is actually received. It is estimated that the typical consumer pays 50 cents per tank of gas extra because of the heat.

While 50 cents per tank of gas may not seem like much, it is estimated that this phenomenon costs consumers in the state of California from 450 million dollars a year according to the Foundation for Taxpayer and Consumer Rights.

"Sales must be honest to be fair," said Judy Dugan, research director of OilWatchdog.org and the FTCR. "Yet the industry from the refinery level on down cheats both motorists and taxpayers by pretending that fuel is 60 degrees in order to fatten their own profits,"

In order to disclose the fact that consumers may not be getting a full tank of gas, ExxonMobil will be adding a decal that explains the phenomenon in its Arizona and California locations.

According to the Oil Express report the decal will read: "This device dispenses motor fuel by volume measured in gallons. It does not adjust the volume for variations in the temperature of the fuel. The temperature of motor fuel affects the energy content of each gallon dispensed."

The decal will be on all pumps in stations owned by ExxonMobil or its franchises. The company also says it will encourage stations that sell the Exxon brand to display the decal.

The FTCR is critical of the move, which they state is simply a measure to prevent lawsuits, not address the problem.

"A cheap decal is like a tobacco pack warning," said Dugan. "It may be Teflon against lawsuits, but it offers no protection to consumers. The cost of each decal may be less than the 50 cents a fill-up that consumers are paying for ghost gas."