Alternative Diesel Fuels Regulation

This page last reviewed on November 17, 2017


ADFPicThrough California and federal fuel policies, consumers are beginning to see increasingly cleaner and more diverse fueling options. The Alternative Diesel Fuels (ADF) regulation is intended to create a framework for these low carbon, and often times lower polluting, diesel fuel substitutes to enter the commercial market in California, while mitigating any potential environmental or public health impacts.  ADFs are those alternative diesel fuels that do not have an established ARB fuel specification in place prior to January 1, 2016.  

The ADF regulation consists of two major parts:
  1. A three stage process for ADFs to be introduced into the California market including, if necessary, a determination of mitigation measures to ensure no degradation in air quality.
  2. In-use requirements for biodiesel as the first ADF.

The ADF regulation consolidates many adminstrative and regulatory practices into one regulation that provides a clear framework for commercialization of ADFs.  The formal framework is necessary for two primary resons.  First, programs such as California's Low Carbon Fuel Standard (LCFS), and the federal Renewable Fuels Standard (RFS) are incentivizing the rapid development of ADFs.  Many of these fuels provide criteria pollutant and toxic air contaminant emission reductions in addition to their greenhouse gas (GHG) benefits.  Second, some ADFs may have adverse effects under certain circumstances.  For these reasons, the ARB adopted the ADF regulation to ensure that ADFs are commcercialized in California under specific requirements and conditions that avoid potential adverse impacts, while realizing the benefits that ADFs can provide.

The first ADF that will be subject to in-use requirements under the ADF regulation is biodiesel.  Fuel specifications and other requirements for future ADFs will be incorporated in the the ADF regulation through the formal rulemaking process.  Biodiesel has particulate matter (PM), GHG, and other emissions benefits; however, testing by ARB and others shows that biodiesel can increase oxides of nitrogen (NOx) under certain circumstances and without considering offsetting factors.  The biodiesel in-use specifications will reduce NOx  from current levels and Californians will continue to experience biodiesel's PM, GHG, and other emissions benefits.

What's New

  • November 17, 2017: ARB staff has posted a revised ADF FAQ and Reporting Form.  Staff is requesting comments on these revisions.  For more information... 
  • August 10, 2017: ARB staff has posted a summary of ADF 2016 reporting.  For more information...
  • July 20, 2017: ARB has approved VESTA™ 1000 under the certification provisions of the Alternative Diesel Fuel regulation as an emissions equivalent additive for use with biodiesel blends B20 and below.  For more information...
  • May 27, 2016: ARB staff has posted updated versions of the ADF reporting form and the ADF FAQ document.  The documents can be found on the ADF documents page.  

Related Links

LCFSCalifornia Air Resources Board

Low Carbon Fuel Standard
Fuels Multimedia Evaluations
LCFSCalifornia Department of Food and Agriculture

Measurement Standards Division

RFSU.S. Environmental Protection Agency

  Renewable Fuel Standard
BFINU.S. Department of Energy

Alternative Fuels Data Center
Provides information on alternative fuels and vehicles including programs, events, tools, data, analysis and trends
Bioenergy Feedstock Information Network
Biomass feedstock information resources from the  U.S. Department of Engergy and other  research organizations.
DODU.S. Department of Defense

 Operational Energy Plans
DoD's energy policy interest in biofuels and alternative fuels as “sustainable and reliable” ways the United States can accomplish the defense mission.

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