California corrects 13 months of diesel data

At least 13 months of flawed California Energy Commission data artificially boosted out-of-state diesel production by California refiners in 2019, according to newly corrected data.

A spreadsheet error increased non-CARB diesel production reported by in-state refiners over the course of 2019 by an average of 30pc, and reduced CARB diesel output by 19pc. The correction reduced total average diesel production during the year by 9pc.

CARB diesel stockpiles averaged 16pc higher in 2019, according to the corrected data, non-CARB diesel stockpiles were 26pc lower, and total diesel stockpiles 7pc lower than originally published.

The correction to California's Weekly Fuels Watch data does not change records reported to the Energy Information Administration (EIA) or used to calculate credits and deficits as part of California's Low Carbon Fuel Standard (LCFS). But the revision better explains what appeared to be a puzzling tilt of California refiners into production of diesel consumed outside of the state.

Corrected data shows that during only three weeks over the course of 2019 did refiners produce more non-California dieselthan California diesel. Previous data showed refiners consistently making more non-CARB diesel fuel beginning in April.

The commission had expected rising demand for renewable diesel in the state to chip away at CARB diesel demand over the course of the year, said Ryan Eggers, supervisor of the commission's transportation fuels data and analysis department.

"The numbers looked pretty close by approximation, and we got fooled," Eggers said.

The numbers grew less reasonable in the second quarter of 2019. CARB diesel output was falling to its lowest levels in decades, and non-CARB production swelled. But the staff focused on CARBOB, the dominant consumer fuel, and the diesel data anomaly festered.

"We sort of lost track of what was going on with the diesel number," Eggers said.

Commission staff reviewed and corrected 2019 data following Argus inquiries to California's Air Resources Board, a separate regulatory body that also scrutinizes state fuel production and consumption. Data changed from January 2019 through the end of January 2020.

Staff will also make a longer-term review of 2018 and older data, Eggers said.

By Elliott Blackburn