School board mulls over bus conversion
LINCOLNTON – With fuel prices hitting an all-time high in recent months, members of the Lincoln County School Board are toying with the notion of converting their school buses to compressed natural gas rather than using diesel fuel.
“It’s definitely a fuel alternative, and it’s been proven to do well in the west,” said Eric Eaker, director of transportation. “But right now, North Carolina only has nine stations that pump natural gas.”
During the Monday night, Aug. 15, Board of Education meeting, Eaker said Lincoln County faces a major hurdle when it comes to fuel conversion for a few reasons.
“The biggest problem we’ve seen is that there isn’t a converter kit for the engines that we currently have in our school buses,” Eaker said. “What you have to do is called an engine swap-out. One of those costs about between $45,000 and $50,000 per vehicle.”
Eaker said there would be two possible pumping systems if the county were to switch to compressed natural gas fueling: a cascading system and an overnight fueling system.
“The cascading system is a fast flow system that allows you to put high density pressure behind the air to fill the buses,” Eaker said.
Eaker said some schools in the west have converted to compressed natural gas, and the overarching choice for a fueling system has been the overnight system.
“The slow fuel system is basically a small pump that restrains pressure back so that it fills overnight,” Eaker said. “At a place like West (Lincoln High School), where you have a lot of buses, you would need a cascading system.”
To get an overnight fueling system set up would potentially cost between $15,000 and $20,000, Eaker said. A high-density air compressor, used for the cascading system, would cost $224,000.
Eaker said another issue the school system might face is that natural gas isn’t directly connected to some schools in the system.
“I don’t think this is anything we should throw out the window at this point,” said Bob Silver, school board finance committee chairman. “I think the savings could be substantial.”
One example of success Silver pointed to was the Tulsa, Okla., school system, which has saved $1 million per year by making the conversion to natural gas with a 176-bus system. Lincoln County has 113 buses in its fleet.
The Tulsa system started conversion of its fleet in 2007 and just finished this year.
Eaker said Charlotte-Mecklenburg tried the compressed natural gas fueling system for some buses in 1997, but stopped using it after about eight years because the bus engines didn’t last as long as the ones powered by diesel fuel.
Eaker said he doesn’t have a definitive time frame for how long it would take the county to start seeing benefits from the conversion.
“Bottom line, here’s my point,” Silver told the board. “We’re talking about $1.81 a gallon to run the bus (with compressed natural gas) as opposed to $4 per gallon now. That’s an increase that we’re encompassing because of the lack of conversion.”