New York City Up to new 475 Compressed Natural Gas Buses
The contract is for 135 40-foot compressed natural gas (“CNG”) heavy-duty transit buses with options for up to an additional 340 CNG buses.
Buses are a pretty green way to move lots of people around in urban area, but how much better are CNG buses compared to regular diesel ones?
The U.S. Department of Energy has some numbers to allow us to compare.
Based on testing by the DOE, “model year 2004 CNG engines produced 49% lower nitrogen oxides emissions and 84% lower particulate matter emissions versus transit buses equipped with model year 2004 diesel engines.” This is particularly important because in urban areas, NOx and PM are the pollutants that accumulate the most and cause smog and bad air quality.
On the CO2 front, the reduction should be of about 25%, depending on the source of the gas (a bigger reduction can be had if biogas from carbon neutral sources is used).
The main downside is that methane emissions can be higher, but this can be mitigated by minimizing leaks and making sure that the refuelling is done properly.