A city experiment to test the efficiency of natural gas-powered vehicles is now under way.

City officials on Wednesday unveiled a new F-150 pickup truck that will serve as a test vehicle to determine whether money could be saved by converting much of the city’s fleet of 500 vehicles to run on compressed natural gas.

“I really want us to explore using natural gas for our trash trucks,” Mayor Bob Schumm said. “I think the payback can be very quick with today’s gasoline and natural gas prices.”

The city, though, is starting with a standard pickup truck that is used by a city streets supervisor. Black Hills Energy, the city’s largest natural gas utility, and Missouri-based Fuel Conversion Solutions donated the conversion kit that allows the truck to operate either with compressed natural gas or unleaded gasoline.

City officials will begin collecting data on the truck, including:

• Fuel mileage. The experts predict the truck will get the same fuel mileage with natural gas as it does with unleaded gasoline. If so, the city would be in line to save on fuel prices for the truck. Currently, it takes about $1.50 worth of compressed natural gas to equal one gallon of gasoline. It takes about $1.75 worth of natural gas to equal one gallon of diesel fuel.

• Reliability. The conversion kit required several new pieces of equipment to be installed on the truck, including a pressurized fuel tank, regulators and fuel injectors. City maintenance crews want to see the reliability of those systems before committing to add more natural gas vehicles to the fleet. They also want to test claims that the engines burn cleaner, and even need to have oil changes performed about half as often as a traditional gasoline engine.

• Fueling. The city will use a compressed natural gas fueling station located at Black Hills Energy’s maintenance shop in east Lawrence. The process to fuel the 20-gallon tank takes about 10 minutes, depending on how full the fueling station’s main holding tank is.

Part of the city’s research into compressed natural gas will examine the feasibility of building a larger fueling station that could quickly fuel large vehicle fleets.

Scott Zaremba, an owner of the local Zarco chain of convenience stores, already has a site plan approved by the city to build a retail compressed natural gas fueling station near Ninth and Iowa streets. Zaremba said he will be watching the city’s experiment closely to determine whether to move forward with project.

“Deciding when to do this is a chicken and an egg sort of deal,” Zaremba said.

He said he has talked to operators of several fleets of vehicles who are interested in trying natural gas but want to see it in action on the local level first.

“We need something like this to get us started,” Zaremba said.

In addition to the city truck, Black Hills Energy operates four vehicles powered by natural gas and has plans for more. Black Hills has had the Lawrence fueling station, which is not open to the public, for a little more than a year. Tim Hess, manager of gas marketing for Black Hills, said the station cost about $150,000. He said larger stations that allow for quicker fueling cost $600,000 to $1 million, depending on several factors.

Zaremba said true retail fueling stations, which will allow motorists to fill their vehicles in about the same time as with a standard gasoline pump, can cost even more. But Zaremba thinks the city soon will be in a position to know whether it wants to add more natural gas vehicles to their fleet.

“I think in the next year or less, they’ll have some good data,” Zaremba said.

Lanny Wagoner, a vice president with Fuel Conversion Solutions, estimated the cost to convert the city pickup truck was about $9,500 to $11,000. He said at today’s prices, it takes about 45,000 miles of use before the fuel savings have paid for the cost to convert the vehicle to run on natural gas.