Clean fuels replaced more than 50% of the diesel used in the state in the first quarter of 2023, according to the California Air Resources Board (CARB). California’s Low Carbon Fuel Standard (LCFS), which requires fuel producers to reduce the carbon intensity of fuel sold in the state, is largely responsible for the shift by encouraging the use and production of cleaner alternatives.

The LCFS program helped to replace nearly two billion gallons of regular diesel fuel in 2022 with a combination of cleaner fuels, including renewable diesel, biodiesel, electricity, and hydrogen. Since compliance began, the program has helped to replace more than 8.6 billion gallons of diesel.

This figure provides perspective on the performance of actual quantities of fuel consumed in California. Each sphere represents a certified fuel pathway; the size of the sphere represents the reported volume of the fuel in 2022, while its position on the horizontal axis indicates the carbon intensity of that fuel. The alternative fuel’s CI value is divided by its Energy Economy Ratio (EER) in order to obtain the EER-adjusted CI value, representing the emissions which occur from the alternative fuel per MJ of conventional fuel displaced. Source: CARB

Carbon intensity for the LCFS program is measured through lifecycle analysis of a fuel which includes all steps from extraction, transport, and production. The LCFS is one of several programs developed under AB 32 (the 2006 Global Warming Solutions Act) to cut California’s emissions of climate warming greenhouse gas.

Other programs include Cap-and-Trade, which establishes a declining limit to emissions allowed in the state by requiring industry to pay for pollution produced. Newer regulations such as Advanced Clean Trucks and Advanced Clean Fleets put in place a phased-in transition to sell and implement clean truck technology in California, in line with Governor Gavin Newsom’s Executive Order calling for all heavy duty vehicles traveling in the state to be zero emissions by 2045.

In July, CARB announced the Clean Truck Partnership with the nation’s leading truck manufacturers, including the Engine and Truck Manufacturers Association and its member companies, and Ford Motor Company, that advances the development of zero-emissions truck technology, adding further momentum to the shift to cleaner transportation fuels.

Compliance with the LCFS began in 2011. The program is designed to lower the carbon intensity in fuels by assessing each step in their production, from extraction to combustion. Fuels are compared to an annually declining baseline. If a fuel has a carbon intensity above that baseline it generates a deficit for the producer. If the intensity is below the baseline it can generate credits which may then be sold to a producer who has a deficit.