Gasoline prices this month in California surpassed $4 a gallon for the first time since 2014, according to the U.S. Energy Information Administration.
Prices in the state average $4.01 per gallon compared to $2.90 a gallon nationally. Prices in California have increased by 75 cents a gallon since December while Brent crude oil prices increased 52 cents a gallon during the same period.
Refinery outages have been attributed to the increase. California is part of the Petroleum Administration for Defense District (PADD). Refinery inputs in PADD began to rapidly decline in March.
The four-week average for regional refinery runs reached 2.37 million barrels per day in mid-April. This is 9 percent fewer refinery runs than the previous five-year average.
This spring, there were several unplanned refinery shutdowns, including one in Benicia, Calif., and two in Carson, Calif.
In addition, regional inventory decreased 8 percent from the five-year average for the week ending May 10, falling to 26.4 million barrels.
It is typical for West Coast gasoline inventories to fall in the spring, but on May 15 inventories were within approximately 600,000 barrels from the lowest point in the previous five years.
California requires a different gasoline specification than the rest of the country, further narrowing resupply options.