Terry’s Take: Summer heat means higher gas prices!

Posted on: 11:02 pm, April 10, 2013, by , updated on: 11:15pm, April 11, 2013

Terry Swails Weather Blog

The approach of summer!  We are all looking forward to those bright warm days and sun in the fun, but it also means pain at the pump as the price of gas increases. While part of this can be attributed to basic supply and demand as more people hit the road for vacations, for many locations there’s actually a difference in the gas you fill up with during the warmer seasons.

Gasoline has what is known as a Reid Vapor Pressure, its vapor pressure as measured at 100 degrees Fahrenheit. The higher the vapor pressure level, the more easily it evaporates. The more gasoline vapor that evaporates into the atmosphere, the more pollution it creates by contributing to ozone production.  The Environmental Protection Agency, is the group behind the seasonal gas transitions and responsible for enforcement.

PAIN AT THE SUMMER PUMP

PAIN AT THE SUMMER PUMP

In essence, summer’s higher temperatures will cause fuel to evaporate more quickly, build up pressure in gas tanks and in rare cases may even cause gasoline to boil. To combat the issue of summer heat increases, gas stations switch over to a different gasoline formula that has a lower RVP, sitting lower than the 14.7 psi average. The end result is gasoline that burns cleaner than what we fill our tanks with in the winter. However, this mixture costs more to produce, and also requires a brief shut down of refineries to make the transition. This temporarily creates shorter gasoline supplies, which again contributes to supply and demand price increases.

REFINERIES TEMPORARILY SHUT DOWN

REFINERIES TEMPORARILY SHUT DOWN

The main difference in ingredients in seasonal gas is the level of butane. It’s an inexpensive additive, but it also has the highest vapor pressure level. It’s able to be used in larger quantities in colder climates, but when the temperatures heat up the butane levels must go down to keep gasoline’s overall RVP low enough to combat the change.

GRIN AND BUY IT!

GRIN AND BUY IT!

For more varied climate areas that participate in this program summer gas comes in May and transitions back to winter in September. The result is lower gas prices for a little over half the year. For areas that have higher temperatures year-round, however, gas prices are consistently higher than in other parts of the country. You can’t win for losing!