Metro’s CNG buses purportedly would deliver buses that “clean up the air” that are fueled from “organic” natural gas. However, this biogas is primarily methane and is essentially indistinguishable from fracked natural gas, with many of the same problems. The burning of biogas releases greenhouse gases such as carbon dioxide (CO2) nitrogen oxides (NOx).
This supposedly clean biogas will be pumped into the existing natural gas pipeline network — but leaks from methane, a greenhouse gas many times more potent than CO2. In California, the Aliso Canyon gas storage facility was the site of the worst methane leak in history, which displaced 8,000 residents. CNG buses simply create the illusion of cleaner transportation, but they “could be a methane-filled Trojan horse, a deceptively veiled prop that ultimately proves destructive,” according to a research fellow at Arizona State University.
The shift to CNG buses reinforces the demand for natural gas and natural gas infrastructure, which may be why these proposals are backed by the oil, gas and utility industires. SoCalGas, which operates the failed Aliso facility, heartily endorsed Metro's CNG bus contract. Natural gas drilling companies like Apache and Chesapeake have promoted the shift to CNG vehicles to sop up demand for their fracked gas. But more investment in natural gas infrastructure prolongs our fossil fuel dependence, delays the shift to clean renewable energy and forestalls any meaningful reductions in greenhouse gas emissions.