California Air Resources Board

CARB's diesel fuel regulations are geared toward controlling criteria pollutant emissions from hydrocarbon-based fuels and are not intended to provide a market pathway for alternative diesel fuels (ADF), such as biodiesel.  With the advent of the policies that incentivize or require ADFs, such as the federal Renewable Fuel Standard (RFS) and the California Low Carbon Fuel Standard (LCFS), there is a clear need to provide a pathway for emerging ADFs to enter the California market.  Over the past several years, CARB staff has endeavored to solicit stakeholder input via meetings and public workshops regarding the need for new regulations to address this gap. Information regarding developing ADF regulatory concepts and processes can be accessed from the ADF websites. 

Under the ADF regulation, biodiesel is considered the first alternative diesel fuel.  Staff has conducted essential research and held many workshops for biodiesel as an ADF.

Biodiesel and Renewable Diesel Test Reports

• CARB Comprehensive B5/B10 Biodiesel Blends Heavy-Duty Engine Dynamometer Testing - June 2014
• CARB B20 Biodiesel Preliminary and Certification Testing - July 2013
• CARB B5 Biodiesel Preliminary and Certification Testing - April 2013
• Final Biodiesel Characterization and NO_X Mitigation Study - October 2011
  • Fuel Comparison Table
  • UCR Letter on Renewable Diesel Fuel Properties
• Biodiesel Fleet Durability Study - July 2010
• Draft Report of CE-CERT Engine Testing on a 2006 Cummins ISM - August 2009

Biodiesel and Renewable Diesel Test Data

• Impact of Biodiesel Blends on a Transport Refrigeration Unit Engine
• Draft Chassis Dynamometer Emissions Test Results for Truck Equipped with a 2000 C-15 Caterpillar Engine
• Draft CE-CERT Engine Dynamometer Emissions Test Results for a 2007 MBE4000 Engine
• 2014 Biodiesel Literature Search Database (xlsx)
• 2014 B5 & B10 Raw NO_X Data (xlsx)
• 2014 B5 & B10 Raw all pollutants Data (xlsx)

Multimedia Evaluations for Biodiesel and Renewable Diesel

Comprehensive multimedia evaluations of biodiesel and renewable diesel were conducted in accordance to California Health and Safety Code (HSC) section 43830.8, which requires a multimedia evaluation to be conducted and reviewed by the California Environmental Policy Council (CEPC).  The purpose and scope of the multimedia evaluation is to inform the rulemaking process and provide the information needed for the development of fuel regulations.

Alternative Diesel Fuels Reporting

Producers, importers, and blenders of biodiesel must submit quarterly reports beginning January 1, 2016.

Renewable Diesel Joint Statement

This is a joint statement by the California Air Resources Board (CARB) and the State Water Resources Control Board intended to clarify questions that have been raised regarding the status of renewable diesel. Renewable diesel should be treated the same as conventional CARB diesel for all purposes, including storage in underground storage tanks (USTs).