Average retail prices for diesel and gasoline continued to drop in the U.S. this week, according to the Energy Information Administration (EIA), with agency also noting that the energy content of gasoline is declining due to more robust use of ethanol.
The national average for diesel declined 2.1 cents this week to $3.635 per gallon, EIA said, which is 23.5 cents per gallon cheaper compared to the same period in 2013.Only the Midwest reported an uptick in diesel prices this week – 5/10ths of a penny to $3.611 per gallon – with every other region in the country reporting a decrease.
The East Coast posted the largest one-week regional decline in diesel prices – 3.8 cents to $3.627 per gallon – followed by California with a 3.7 cent dip to $3.876 per gallon.
Gasoline prices also continued its downward track, with the national average dropping 6.4 cents this week to $3.056 per gallon; some 23.8 cents cheaper per gallon versus the same week in 2013, EIA noted.
Two regions marked dips below the $3 per gallon mark this week: the Lower Atlantic, posting a 9.7 cent drop to $2.947 per gallon, and the Gulf Coast, where gasoline declined 8.2 cents to $2.830 per gallon.
The West Coast – both with and without California’s prices included – witnessed the biggest one-week drop in gasoline prices this week; 10 cents per gallon to $3.324 and $3.211 per gallon, respectively.
Additional research posted by EIA this week noted that more ethanol and other oxygenates are being used to make gasoline today, with their share of total gasoline volumes increase from 2% in 1993 to nearly 10% in 2013.
As a result, the agency said its estimate of motor gasoline's average energy content per gallon has declined by about 3% over this 20-year period.
While such additives are designed to reduce the air pollution produced by the combustion of gasoline, they also result in a lower “heating value” compared with conventional gasoline – translating to fewer miles per gallon, because they have lower energy density, EIA explained.