CARB Approves Amendments to Reduce NOx Emissions in B20 Biofuels

(Transport Topics) The California Air Resources Board has conditionally approved a slate of regulatory amendments intended to more closely monitor the additives blended into B20 biodiesel that so far have not been deemed effective at mitigating oxides of nitrogen in the alternative diesel fuel.

However, opposition from biodiesel industry representatives persuaded the board to invoke its 15-day rule, giving CARB Executive Officer Richard Corey discretion to tweak the rule before it becomes official.

“I’m frankly a little taken aback by the response from our many friends and constituents in the biodiesel industry in this one,” CARB Chair Mary Nichols said. “I don’t think that was certainly where we started.”

In an April 23 presentation to the CARB board, staff members said that recent testing conducted by the University of California-Riverside on six additives to B20 biodiesel showed they failed to “effectively mitigate to the regulatory standard.”

“The test results raise significant questions both as to the specific additives addressed by the testing, and regarding how best to ensure appropriate performance of additives and formulations generally under CARB’s Alternative Diesel Fuel regulation going forward,” the university testers reported.

CARB’s alternative diesel fuels regulation, originally adopted in 2015, governs the introduction and use of B20 biodiesel, which currently accounts for from one-fourth to one-third of all biodiesel on the California market, according to Jim Guthrie of CARB’s Industrial Strategies Division.

“Biodiesel is one of the low-carbon fuels that has greenhouse gas emission benefits, and also has particulate matter benefits,” Guthrie told board members attending the April 23 virtual meeting. “However, biodiesel use in limited circumstances has been shown to increase NOx emissions, leading to air quality and public health impacts.”

NOx emissions from B20 biodiesel additives tend to be higher in older engines, according to CARB.

The modification to the regulation, which becomes effective Jan. 1, calls for biodiesel fuel blending and emissions testing to be observed by independent state-licensed professional engineers at two emissions-testing labs, and tougher chain of custody requirements.

“We are concerned primarily with two issues about the ADF rule as it may present barriers to our business,” Mary Solecki, representing World Energy, told the board. “These issues are the proposed blender issue and the dual lab certification.” READ MORE