The city of Corpus Christi expects to see $1 million in gasoline savings in the next 10 years, thanks to a policy change that focuses on purchasing vehicles that use compressed natural gas as fuel.
The city already has 56 CNG-powered vehicles in its fleet of around 1,700, and recently made a lease purchase of 14 new vehicles -- eight brush trucks and six refuse trucks -- for about $3.47 million.
In the next 10 years, Fleet Maintenance Director Jim Davis expects that as many as 430, or about 25 percent, CNG vehicles will be included in the fleet. Officials hope to eventually see 80 percent of the fleet as CNG-powered vehicles.
Davis described the policy change in a presentation last month about the new vehicle-purchasing standards as an "epic event."
The city is limited in the kinds of vehicles that can be purchased as CNG-ready, because some simply aren't on the market yet, he said in a later interview. But that's expected to change in the future.
"We're right now at the beginning of manufacturers producing CNG vehicles, so what's going to happen is the numbers are going to ramp up steeply," Davis said.
The rising cost of gasoline is driving that market, he said: A gas gallon equivalent of compressed natural gas averages about $1, about $2 less than the average price of gasoline.
Although the vehicles are more expensive upfront, there are savings in maintenance and fuel costs that exceed the initial investment, officials said. The larger the vehicle, and the more miles driven, the higher the savings.
For example, a diesel refuse truck with a seven-year life costs $280,000 for the vehicle, about $247,719 in maintenance and $232,992 in gasoline, according to Davis' presentation. The same vehicle, purchased with a CNG engine, costs $327,340, but maintenance and fuel costs are lower -- an estimated $222,947 and $77,664, respectively. The difference amounts to a $132,760 in savings by using a CNG compatible truck, council documents state.
Savings, however, are significantly smaller with a smaller truck. Officials estimate a $8,743 in savings when using a CNG instead of a gasoline-fueled, half-ton pickup over 10 years, officials said.
It's expected that the policy change will result in $1 million in fuel and maintenance savings over the course of the next 10 years. In just three years, it's believed the city could save more than $400,000, according to a graph included in the council's presentation.
CNG is also a cleaner-burning fuel, meaning that vehicle emissions are reduced by 10 percent with a CNG vehicle over gasoline-powered truck, and 20 percent with a CNG vehicle over a diesel-powered truck.
The city maintains three CNG fueling stations -- one each at City Hall and the Gas Department, intended to only serve city-owned vehicles -- and one on Hygeia Street, which serves privately owned vehicles as well as city vehicles.
It's hoped that the number of fill stations will increase, as well as revenues, said Bill Mahaffey, assistant director of the gas department.
Debbie Marroquin, director of the Gas Department, told the City Council last week that the department is already looking at two locations for CNG distribution in Flour Bluff, as well as near the airport.
The policy would require that any request for a vehicle that does not use CNG -- excluding those that don't drive enough miles that a CNG vehicle would result in savings, and barring those vehicles that are not available with CNG compatibility -- would need written approval, according to the presentation.
"The piece that I look forward most to in that policy is the scanning every vehicle. It starts with the presumption that we're going to go with gas unless you can convince us otherwise," said City Councilwoman Colleen McIntyre in the meeting.
Other entities are also purchasing CNG-compatible vehicles, citing gas cost savings. Aransas County ISD recently converted six of its 40 school buses, and the Corpus Christi Regional Transportation Authority moved forward this summer with plans to use $4 million to convert 23 buses in its fleet.
