CHEYENNE -- Interest in hybrid motor vehicles rises and falls with the price of gasoline.
Today, with gasoline prices relatively low, some of the steam has gone out of the movement to compressed natural gas vehicles or the hybrids that also use gasoline.
Interest was sky high in 2011 when the Legislature authorized two state agencies -- the Department of Administration and Information and the Department of Transportation -- to retrofit existing vehicles or to buy new ones capable of running on natural gas or a combination of natural gas and gasoline.
The Legislature authorized $200,000 for the pilot program, enough to retrofit 10 vehicles for each of the two departments.
A report from the state's Economic Analysis Division issued at that time said the natural gas vehicles reduce carbon monoxide emissions by 90 to 97 percent.
But the driving range of the vehicles is limited, the report warned.
At the time the state had only three compressed gas stations open to the public. They were located at Cheyenne, Rock Springs and Evanston.
Still eager to take advantage of the environmental benefit of the vehicles with possibility of cost savings, the Legislature in 2013 passed a law requiring state agencies, the community colleges and the University of Wyoming to replace half their replacement vehicle purchases with models that operate on compressed natural gas or on CNG and gasoline or diesel.
The requirement is limited to vehicles stationed in areas currently served by a CNG filling station or those vehicles within six months of their scheduled replacement.
The downside has turned out to be the cost. The compressed natural gas hybrids cost about $10,000 more than a gasoline-only vehicle.
The price differential can be problematic for agencies trying to hold the line on budgets in the current period of declining revenues.
"Challenge" is a the word used by state officials to describe the work involved in the program.
The state motor pool, a division of the Department of Administration and Information, has 11 CNG vehicles, mostly passenger and light duty types.
The roster includes two mid-sized SUVS, one full-sized SUV, five pickups, two sedans and one all-CNG van.
Annette Spitsbergen, director of the state motor pool, said the location of the CNG fueling stations is an issue in scheduling the vehicles for employee travel.
"The question is if people are comfortable they can find fuel when and where they need it," she said.
The number of stations has been expanded to include Riverton, Afton and Pinedale, in addition to Cheyenne, Rock Springs and Evanston. A station is scheduled to open in Casper in 2016 and another is in the works for Rawlins.
The shortage of CNG stations is why the state and WYDOT motor pools run their 100 percent CNG vehicles in Cheyenne only. If the drivers were to run out of fuel in the boonies, far from a station, they would be out of luck.
With a hybrid, this is not a problem. Spitsbergen told of traveling in a hybrid SUV with an 18-gallon tank from Cheyenne to Riverton recently --- a distance of 270 miles ---before the natural gas ran out. The vehicle then automatically shifted to gasoline operation.
Nationally automobile buyers are going back to the big gas guzzlers they abandoned when the cost of filling the tank was staggering.
According to an article in "Automotive News," the danger of falling oil prices is that the billions of dollars invested by automakers on smaller and more fuel-efficient vehicles, lighter vehicles and hybrids will be lost.
Yet, with the lower gas prices it is harder to show a better return on the state's investment in the hybrid vehicles, said Tim Thorson, policy and planning coordinator for the Department of Administration and Information.
He expects gas prices to rise again, however.
Moreover, the program reflects the Legislature's interest in green technology.