The gas debate is back at Lawrence City Hall.

City officials have decided to hold off on purchasing three new diesel and diesel/electric hybrid buses until staff members do another round of research on the feasibility of buses that are powered by compressed natural gas.

“This seems like the sort of thing that if we don’t at least consider making the switch, we may look back 20 years from now and regret it,” said City Commissioner Jeremy Farmer.

City transit leaders, however, thought they already had crossed this bridge, conducting a feasibility analysis of compressed natural gas versus diesel buses and diesel/electric hybrid buses four years ago. But in the meantime, natural gas prices have plummeted as new domestic supplies have been discovered using fracking technology.

“I think the numbers probably have changed quite a bit since we last looked at it,” said Mayor Mike Dever.

The U.S. Energy Information Agency reports that the average price of diesel fuel nationally is about $3.90 per gallon. Several national media reports peg the average price of compressed natural gas at about $2.10 per gasoline-gallon-equivalent, although that price has dropped to about $1 per gallon-equivalent in some gas-rich portions of the country.

“It would be a major change in how we do business,” Dever said. “But would the savings be worth it? They might be, but we have to study a lot of factors.”

The cost to install a quick-fueling compressed natural gas station is chief among them, city leaders said. The city has had access to the fueling station at the Black Hills Energy maintenance shop in East Lawrence, but it is a slow-fueling system that would require a bus to be connected for several hours to fill.

The city has received a federal grant to install a compressed natural gas fueling station at its maintenance garage near 11th and Haskell, which the city will use to test a new CNG-powered trash truck and a more traditional pickup truck.

That new station also will be slow-fueling, in large part because a quick-fill station could cost as much as $2 million to construct, Dever estimated.

Figuring out where to put a facility also may be tricky, Dever said. He said the city would also want to be able to use CNG to power vehicles other than transit buses, such as the city’s fleet of trash trucks. Currently, the city’s bus fleet is based in northern Lawrence in the Santa Fe Industrial Park near the West Lawrence Kansas Turnpike interchange. The city’s trash trucks and other public works vehicles are based in East Lawrence near 11th and Haskell. A fueling station to accommodate both fleets likely would require significant changes in operations for both divisions.

There may be an even tougher puzzle for city officials to solve, though: What’s the likelihood that natural gas prices are going to remain significantly less than oil prices in the future?

“Is the fracking industry a sustainable one? Because that is really what this is all built on at the moment,” Dever said.

The idea of cheaply fueling transit buses is catching the attention of some members of the public. Lawrence resident Graham Kreicker recently urged commissioners to delay the purchase of diesel buses until the CNG options had been further explored. He also told commissioners that several communities across the country are getting assistance from natural gas companies to install quick-fill fueling stations, in exchange for signing long-term natural gas contracts.

“There are communities that have gotten over the hurdles you are concerned about,” Kreicker told commissioners. “We should be looking toward having a natural gas fleet, and we should encourage the school district to do the same.”

There also has been interest from the private sector to build a quick-fill natural gas station in the city. Scott Zaremba, an owner of the Zarco 66 chain, has filed plans to add natural gas fueling stations to his property near Ninth and Iowa streets. But those plans haven’t moved forward. He previously has said he needs a large customer, such as the city, the school district or Kansas University, to commit to using the fuel source.

Kreicker, after meeting with commissioners, said he doesn’t work for the natural gas industry or have any other sort of professional interest in the subject. But he said he does have a personal motivation for bringing up the issue.

“I want to buy a gas-powered Honda Civic, and I want some place to fill it up,” he said.

City staff members are expected to deliver a report to commissioners in the next several weeks.