When it's time to refuel this city's small fleet of government cars and trucks, the filling station attendant bypasses the gas tank and heads under the hood. There he plugs a thin hose into a regulator valve. The resulting sound is nothing like the usual hum of gasoline going into the tank.
"You'd think it was air to listen to it," says Oliver Van Meter, Henderson's director of public utilities, who has just pulled his official white car into the station for refueling. "It's kind of like getting a flat tire filled up."
What Henderson uses -- and what a number of other cities are considering using -- is compressed natural gas. City vehicles here carry anywhere from one to four heavy white steel cylinders of the fuel in their trunks. Each cylinder contains the equivalent of 3.2 gallons of regular gasoline. The natural gas gets roughly the same mileage as gasoline but at about one-fourth the cost.
Most city vehicles operate within a radius of five miles of City Hall -- but if fuel runs dry before a return to the city's one compressor station is possible, the driver simply shifts a lever near the steering wheel and switches to a backup gasoline tank. A gauge under the dashboard that translates measurements of temperature and pressure of the natural gas into cubic feet lets the driver know exactly how much fuel is left.
When city officials here were searching for new ways to economize a few years back, they first looked into electric cars and propane fuel. But they decided the first was not versatile enough for the cost involved and the second was not stable or safe enough to meet their standards.
One key reason Henderson eventually settled on natural gas is that the city happens to own its own natural gas company which is expected to yield the city $ 900,000 in surplus revenue this year. Aside from the brief national crisis in natural gas supplies four or five years ago, the city has had, and expects in the future, no problem in getting as much of the fuel piped in as it needs.
City officials readily admit that the initial cost of converting Henderson's fleet of 65 cars and trucks is considerable -- an estimated $183,000. But they are expecting a full payback of costs within two years. Though they admit much depends on the future price of gasoline, city officials expect to save $100,000 a year. Added advantages, they say, include less pollution (natural gas is clean- burning and leaves no carbon buildup) and lower maintenance costs in terms of fewer tune ups and oil changes needed.
Henderson is the first city in Kentucky trying the natural gas alternative. Some cities in the South and West have been trying it longer, and their largely successful experience helped persuade Henderson to take the plunge. But a number of other cities looking on with interest have been hesitant to follow suit because of the high initial cost involved and a lingering concern about the future availability of natural gas, according to Wally Gernt, director of the municipal energy program of the National League of Cities.
"Many cities are looking at it," he confirms, "but a lot don't have the up-front capital to make the commitment and their cost benefit studies sometimes show it's cheaper to stay where they are."
One cost advantage, as Henderson sees it, is that the conversion materials can be removed from any vehicle and put on any replacement vehicle added to the fleet.
At the moment the city's fire trucks, garbage fleet, and buses, many of which run on diesel fuel, are not equipped to run on natural gas. But Mr. Van Meter says that could change as vehicles are replaced.
Not everyone involved takes to the change with immediate enthusiasm, he admits. Police, who often spend more working hours in their cars than other city employees, tend to be the hardest to convince. Most of their cars are being equipped with three cylinders so that they will have to fill up less often.
Some city workers complain that they don't get the same power thrust with natural gas. But Mr. Van Meter, who says he thinks the ride on natural gas is smoother than on gasoline and that the only drawback is a slight hesitation in switching from one fuel to the other, counters: "Some hot rodders don't like anyting if they can't burn rubber."
He contends that after a few days of driving, most city employees get used to the change and stop complaining. It behooves them. Because Henderson is so serious about its commitment to fuel the local fleet on natural gas that the employee who switches to gasoline when his alternate tank runs dry is required to radio in to headquarters the reason why.
"We don't want them using gasoline at all if they don't have to," explains Mr. Van Meter.