GoRaleigh passengers are beginning to ride on new city buses that are notable for the kind of fuel they use.
The 40-foot buses run on compressed natural gas and are the first of their kind in the Triangle. The city has bought 17 of them and this week began mixing them in with GoRaleigh’s fleet of 100 buses that until now have all been fueled by diesel.
Aside from being shiny and new, the buses may not seem all that different to passengers at first, said Marie Parker, the general manager for GoRaleigh operations. The engines are quieter, Parker said, and the acceleration is slightly smoother, but otherwise they look similar to other GoRaleigh buses except for the compartment on the roof where the natural gas tanks are stored.
The big difference is what comes out of the tailpipe. Citing data from the U.S. Department of Energy, Parker said buses that run on compressed natural gas or CNG produce 6 to 11 percent less carbon dioxide and nitrogen oxides, two greenhouse gases that contribute to climate change. The Union of Concerned Scientists, a nonprofit advocacy group, cites similar reductions compared to diesel, but notes that leaks of the powerful greenhouse gas methane from natural gas buses and fueling stations can erase those gains.
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A clear pollution benefit is the lack of black smoke billowing from the back of CNG buses.
“It eliminates particulates — the actual physical stuff in the air — almost 100 percent,” Parker said.
The CNG buses are built by Gillig, the same company that made GoRaleigh’s diesels. They cost $565,000 each, about $45,000 more than a diesel bus, Parker said. But with natural gas costing less than diesel, the city expects to make up the difference in less than four years and come out ahead over the buses’ 12-year lifespans, she said.
GoRaleigh plans to gradually replace its retiring diesel buses with CNG until 75 percent of the fleet is running on natural gas, a goal set by the Raleigh Transit Authority last year. The remaining 25 percent of the fleet could be another type of fuel, such as electricity or some sort of hybrid.
The switch is part of a larger effort by the city to improve energy efficiency and reduce air pollution by switching to alternative fuels which started in 2002. Dozens of city vehicles already run on something other than standard diesel or gasoline, including propane-powered police cars and garbage trucks that use biodiesel.
To make the conversation to CNG, the city is building a new refueling station at the GoRaleigh headquarters off Poole Road. Most of the $5.3 million cost of the station will be covered by grants and $1.5 million from the half-cent sales tax for transit approved by Wake County voters in 2016.
The 17 new CNG buses will not be used on any particular routes, said GoRaleigh spokeswoman Kelly Wright. Buses are assigned to new routes each week, Wright said, so riders all over the city may get to experience them at some point.