In October 1994, the LA Metro Board established a policy requiring all future bus procurements be alternative fuel initiative (AFI) vehicles.
Initially, these new buses included methanol, liquid natural gas (LNG) and compressed natural gas (CNG) buses. When choosing these fuel types, the Metro Board considered the availability of technology, cost and the ability to retrofit the existing fleet and fueling infrastructures. LA Metro found that of their initial technology investments, CNG was the most viable way to meet the AFI policy.
In 2014, LA Metro transitioned from CNG to "renewable natural gas" to further reduce the emissions impact. Renewable natural gas, or biomethane, is the gaseous product of the decomposition of organic matter that has been purified as vehicle fuel. The combination of low-NOx engines and biomethane from landfill gas initially reduced the fleet’s annual greenhouse gas emissions by up to 75 percent. Now, LA Metro operates a 100-percent natural gas bus fleet and has reduced NOx emissions by 89 percent since 2008.
LA Metro uses their natural gas vehicles in daily heavy duty fixed route services. "Metro has an active fleet of 2,194 natural gas buses with an additional 32 buses designated for special assignment," says Cris Liban, Los Angeles County Metropolitan Transportation Authority Executive Officer of Environmental Compliance and Sustainability. "There are no plans to expand the fleet of CNG buses; however, there are ongoing procurements for additional CNG buses to replace CNG buses being retired."
When LA Metro decided to transition from traditional fuels to CNG, they had to build new on-site fueling facilities. Liban says that there were no additional adjustments to the CNG fueling system as they transitioned from CNG to renewable natural gas.
"New propulsion systems will bring new fueling processes and infrastructure," Liban adds. "Staff will require extensive training on the operation and maintenance of this new equipment. When implementing new technologies, field conditions will present additional challenges to vehicle and equipment maintenance."
Despite the challenges of the initial investment, LA Metro has found that natural gas vehicles are a step in the right direction towards the organization’s ultimate goal of a zero-emissions fleet.
