CNG Environmental and Economic Benefits Flashcards

CNG produces lower levels of which air pollutant, making it preferred in urban areas with smog concerns?

Answer: Nitrogen oxides (NOx)

CNG produces significantly lower NOx emissions compared to diesel, reducing smog formation in urban environments.

What is the primary domestic source of natural gas used for CNG fuel in the United States?

Answer: Shale gas extraction (hydraulic fracturing)

The majority of U.S. natural gas, including that used for CNG, comes from domestic shale gas extraction through hydraulic fracturing.

Renewable Natural Gas (RNG) used as CNG fuel is typically sourced from which waste stream?

Answer: Landfill biogas and wastewater treatment plants

RNG is produced by capturing and processing methane from landfills and wastewater treatment facilities, making CNG carbon-neutral or carbon-negative.

Which CNG emission benefit makes it particularly attractive for fleet operators subject to EPA's National Ambient Air Quality Standards (NAAQS) compliance zones?

Answer: Near-zero particulate matter and lower NOx emissions

CNG's near-zero PM and lower NOx help fleet operators comply with NAAQS in nonattainment areas where air quality standards must be met.

For a transit agency evaluating a switch from diesel to CNG buses, which total cost of ownership (TCO) factor most commonly offsets higher vehicle purchase prices?

Answer: Lower fuel cost per mile over the vehicle's lifetime

Lower CNG fuel costs per mile, accumulated over hundreds of thousands of miles, typically offset the higher initial purchase price of CNG buses.

Which carbon accounting standard allows fleet operators to claim carbon-negative status when using RNG-sourced CNG?

Answer: EPA's Renewable Fuel Standard (RFS) pathway credits

EPA's Renewable Fuel Standard assigns RNG pathways (e.g., landfill gas) with carbon intensity scores that can be carbon-negative, qualifying for D3 or D5 RINs.