The California Air Resources Board (CARB) has conducted emissions testing that showed that tested additives failed to effectively mitigate to the regulatory standard. These 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 the ADF regulation going forward.
Accordingly, CARB intends soon to propose modifications to the ADF regulation that will ensure that additives perform consistently with all regulatory requirements.
The Alternative Diesel Fuels (ADF) regulation is intended to create a framework for 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 CARB fuel specification in place prior to 1 January 2016.
The ADF regulation consists of two major parts:
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.
In-use requirements for biodiesel as the first ADF.
The ADF regulation consolidates many administrative and regulatory practices into one regulation that provides a clear framework for commercialization of ADFs. The formal framework is necessary for two primary reasons, CARB says.
First, programs such as California's Low Carbon Fuel Standard (LCFS), and the federal Renewable Fuel 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, CARB adopted the ADF regulation to ensure that ADFs are commercialized in California under specific requirements and conditions that avoid potential adverse impacts, while realizing the benefits that ADFs can provide.
The first ADF that is subject to in-use requirements under the ADF regulation is biodiesel.