It was another toasty day on June 19, when representatives for the California Division of Measurement Standards showed up at a gas station in Riverside to check the temperature of the gasoline in the tanks.
What they discovered lent evidence to the allegation that consumers are being shortchanged by gasoline retailers and the oil industry.
The temperature in the underground tanks at the station was 94.4 degrees at 1 p.m. that afternoon, hotter than the roughly 90-degree air temperature, according to the agency's official log.
The measurements were part of a statewide survey that is coming amid allegations that an annual $2-billion rip-off is occurring nationwide because of hot gas.
As students of high school chemistry know, some liquids, particularly gasoline, expand when they get hot. But a gallon of expanded hot gas contains less energy, even though gas stations charge the same amount.
The energy content of a gallon of gasoline is based on fuel at 60 degrees. At the wholesale level, all transactions of gasoline are adjusted for the volume of gasoline or diesel when the fuel is at 60 degrees.
Each 15 degrees above the 60-degree standard increases the volume of the fuel by 1%. So each gallon of that 94.4-degree gasoline in Riverside contained 2% less energy.
You might say that amounts to a few cents per gallon. But the cents add up. The Owner-Operator Independent Drivers Assn., an organization representing truck drivers, estimates that the oil industry pockets about $2.3 billion annually from such overcharges. Long-haul truckers, who drive more than 100,000 miles per year, can get dinged by more than $700 annually, the group says.
"Southern California is the epicenter for this problem," John Siebert said. It has high temperatures, lots of cars and obviously a layout that requires absurd amounts of driving.
The association's estimates and other similar estimates are based on gasoline temperature data compiled by the National Institute of Standards and Technology, using environmental monitors on underground tanks at 1,000 stations across the nation. The data showed that gasoline in many middle-tier and Southern states is consistently above 60 degrees. In some cases, temperatures have popped over 100 degrees, said Siebert.
