CARB Issues Biodiesel Proposal

STREATOR, Ill. (DTN) -- The California Air Resources Board issued a preliminary regulatory proposal for the use of biodiesel as an alternative diesel fuel.

CARB expects that the proposal would form "a major element of a comprehensive" alternative diesel fuel regulation for CARB's consideration in 2015, the state regulator said in a notice late Tuesday, July 29.

The regulation goals are to establish a process governing the commercialization of new alternative diesel formulations in the state and establish special provisions for biodiesel as the "first recognized" alternative diesel to permit its use in commercial fuel market blends.

"In general, staff found that biodiesel use results in emissions reduction of total particulate matter, toxic diesel exhaust particulate matter, hydrocarbons and carbon monoxide, but increased oxides of nitrogen (NOx) emissions in certain circumstances," CARB reported.

NOx emissions increase 1% in blends containing 5% soy methyl ester biodiesel but no NOx increases occur in blends containing 5% animal tallow-based biodiesel, CARB reported.

NOx emissions increase 2% in 10% SME biodiesel blends and 4% in 20% SME biodiesel.

"Biodiesel made from animal tallow general exhibits about half or less the NOx increased compared to soy-based biodiesel," CARB said.

On or after Jan. 1, 2016, all biodiesel blends that reach the NOx significance threshold would be required to mitigate NOx increases to "ensure no significant impacts on public health," CARB said.

Biodiesel blends above 1% for soy-based biodiesel is the NOx significance threshold, CARB proposed.

To mitigate NOx in biodiesel, CARB is proposing biodiesel blends containing more than 1% soy or non-animal based feedstocks be mitigated by one of the following options: use of di-tert-butyl peroxide NOx reducing additive; use of co-blended renewable diesel; certification of biodiesel blends or additives; or "contractual arrangements to ensure commensurate use of biodiesel and renewable diesel in the same area and timeframe."

CARB is soliciting public input on alternative diesel fuel approaches. The deadline for submission of alternatives relating to economic impacts is Aug. 15.

(BM/AG)

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