The government's energy statistics arm calculates refinery utilization as gross inputs divided by the latest reported monthly operable capacity. While inputs are based on weekly surveys, capacity relies on a lagging, monthly tally. The latest available is from January.
The utilization data is closely watched by financial markets and energy companies as an indicator of future supplies of gasoline and diesel.
The data mismatch stems from a recent Exxon Mobil Corp expansion at its Beaumont, Texas, refinery, which added up to 250,000 barrels per day of processing capacity. However, that capacity will only be recorded in EIA's March monthly report, due out at the end of May.
As a result, U.S. Gulf Coast refinery utilization figures "may increase to abnormally high levels" for several weeks, the EIA said. The expansion also will be excluded from a mid-year U.S. report that measures refining capacity on Jan. 1, the EIA added.
The warning comes as the EIA has come under criticism for high adjustment figures in the weekly oil inventory data, which it uses to balance demand and supply.
The inventory adjustments, which at the peak rose above 2
million barrels per day, were due to crude oil blending and
under-reported oil output, the EIA has said, adding it would
change its surveys and accounting methods.
(Reporting by Arathy Somasekhar in Houston, Editing by Nick
Zieminski)
