California’s natural gas vehicles achieve first carbon-negative milestone

The energy weighted carbon intensity (CI) value of California’s natural gas vehicle portfolio in the Low Carbon Fuel Standard (LCFS) programme achieved carbon-negative status for the first time in 2020.

Data from the California Air Resources Board (CARB) for the second quarter of 2020 shows the CI value was below zero at 0.85 gCO₂e/MJ – the first time in the history of the LCFS programme that any low-carbon fuel portfolio has achieved carbon-negative status.

California’s LCFS, which measures the climate impact of various motor vehicle fuel pathways, is a market-based incentive programme designed to decrease the carbon intensity of California’s transportation fuel and instead provide a range of low-carbon and renewable fuel alternatives, reducing dependency on petroleum and achieving air quality benefits.

The CI of any given fuel measures all greenhouse gas (GHG) emissions associated with the entire life-cycle of a transport fuel, including production and consumption. Transport fuels with low- or negative-carbon intensity scores are better for the environment as they produce less climate-altering GHG emissions.

Todd Campbell, chair of the California Natural Gas Vehicle Partnership (CNGVP) and vice-president of public policy and regulatory affairs at Clean Energy, said: “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.

“Both the short- and long-term climate benefits of this achievement are extremely significant. 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 is providing the most substantial and cost-effective contributions towards California’s goals to reduce criteria and GHG emissions while eliminating the use of diesel in favour of renewable, low-carbon fuels.”

Renewable natural gas (RNG), derived from organic sources including dairy waste and food waste, has the lowest CI rating of all fuels in CARB’s LCFS programme.

Many forms of RNG, such as that produced from food and green waste, have a carbon-neutral and even carbon-negative rating. Other forms of RNG, such as that produced from dairy waste, can have CI ratings that are 200-300% lower than even a battery electric vehicle powered by renewable energy such as solar or wind.

The Q2 2020 data from CARB’s LCFS programme confirms another significant milestone – RNG made up nearly 90% of all natural gas vehicle fuel in the programme and consumed in California in the first half of the year.

Looking ahead, the volume and CI benefits of RNG consumed in California will continue to grow, according to the CNGVP. More than $1 billion of investment is currently taking place in California to develop a range of in-state RNG production projects. As the state continues to source increasing amounts of transport-grade RNG from projects from carbon-negative sources, such as dairy biogas, the average CI of California-produced RNG will continue to improve.

“We are thrilled to see the growing use of low-carbon RNG by our customers in California and across the US,” said Tom Swenson, vice-chair of the CNGVP and business development manager for Cummins.

“Fleets are increasingly interested in taking real and immediate actions on climate change and local air quality. This one-two punch of RNG in an ultra-clean engine allows fleets to achieve cost-effective carbon-negative operations right now in a vehicle that meets their operational requirements.”