Recent data from the California Air Resources Board (CARB), show that the carbon intensity (CI) value of California’s natural gas vehicle fuel portfolio in the Low Carbon Fuel Standard (LCFS) program was below zero.
This first-time accomplishment for the LCFS program means that not only are these vehicles producing zero emissions, the use of renewable natural gas is actually reducing overall emissions even more.
“Given the large and growing volume of heavy-duty natural gas vehicles already hard at work on California’s roads, this is an extremely significant milestone,” said Todd Campbell, chair of the California Natural Gas Vehicle Partnership (CNGVP) and vice president of public policy and regulatory affairs at Clean Energy. “When combined with the fact that most natural gas vehicles recently placed into service are powered by near-zero emission engines, the natural gas vehicle industry is providing the most substantial and cost-effective contributions towards California’s goals to reduce criteria and greenhouse gas emissions while eliminating the use of diesel in favor of renewable, low carbon fuels.”
To calculate the “carbon intensity” of a fuel, all greenhouse gas emissions associated with the entire life cycle of a transportation fuel, including production and consumption, are factored in to the final number. By capturing and processing the methane emitted from organic sources including dairy waste, wastewater treatment plants, food and green waste, landfills, and forest management, renewable natural gas (RNG) has the lowest carbon intensity rating of all fuels in the program. Some forms of RNG, such as that produced from dairy waste, can have carbon intensity ratings that are 200-300% lower than even a battery-electric vehicle powered by renewable energy such as solar or wind.
RNG or biomethane as it is called outside USA & Canada can be used as a replacement for conventional natural gas in transportation without any modification, as it is essentially the same molecule as fossil natural gas. Conventional and renewable natural gas can be blended at any percentage without any difference to the engine. This is totally different to other biofuels such as bioethanol or biodiesel, which are totally different to their conventional counterparts and can't be blended at high percentages without substantial modifications and implications to the engines.
Source: CNGVP & GGM