Better Roads Staff
Green as the Driven Snow
Can you fight the white with the green?
As the push to make fleets greener continues to build up steam, alternative fuel power options are coming under increased scrutiny.
Questions are being asked about efficiency, power, sustainability and even operator friendliness. But the questions are coming at a time when alternative fuels vehicles may be on the verge of a breakthrough.
At one of the best attended educational sessions at the at the recent 2012 American Public Works Association (APWA) Snow Conference, host city Milwaukee outlined its progress to a winter weather fleet that will increasingly rely on natural gas, as will other vehicles of the city’s barns.
When Milwaukee first attempted an alternative fuel initiative in 1980, the initiative to use compressed natural gas (CNG) for its fleets didn’t unfold as seamlessly as had been anticipated. The engines in two Dodge pickup trucks were modified, and CNG tanks took up valuable space in the pickup box. The pickups broke down often, harnessed very low power and could only travel within a 30-mile range.
The city tabled the idea for a while, but then in 1992-1994, Milwaukee moved forward with its second initiative. This time, seven units were converted to CNG, including a pickup, cars, a police cruiser, a small dump truck and a medium-duty truck. This time, the CNG conversion used up about half of the space in the car trunk or pickup body with a system pressure of 3,000 psi. However, the city made a dual-fuel conversion so that if a truck or other equipment couldn’t get enough CNG, a switch would allow it to be run on gasoline. “We were afraid operators would forget about CNG [and just use the gasoline capabilities] so we installed hour meters,” says Jeffrey Tews, fleet operations manager for the City of Milwaukee.
Now Milwaukee is getting into CNG for the third time. “We tried in 1980 with little success and then again in 1992 with moderate success, and now we are hoping the third time is a charm.”
Milwaukee is building two of its own compressing stations that will be able to handle up to 30 trucks per hour at 3,600 psi. The stations are being built from $3.6 million in grant money through the American Reinvestment and Recovery Act (ARRA), a.k.a., the stimulus. Twenty-one of the city’s refuse trucks – which are also used in its winter maintenance program – are being converted to CNG.
“Fossil fuels are stable. They have been around for 300 million years. Biodiesel is ‘unstable’ – not tried and true like fossil fuel. It’s still undergoing chemical changes.”
– Rich Cregar, Wilson Community College, N.C.
With natural gas, a special ventilation system is needed. The distance of lighting fixtures from the fuel source must also be measured for safety. “The light fixtures need to be a certain distance [from the ceiling],” Tews points out (escaped gas rises). “We also need to have a very modified ventilation system.” Check with your fire marshal if unsure about working on alternative fueled vehicles in your garage.
Cost assessment also plays into the decision on whether an agency can or even should be able to move into alternative fuels. Preventive maintenance (PM) regimens will be more extensive. A different motor oil must be used and maintenance is more than just a minor valve adjustment, Tews says. “Now you have to change out the spark plugs, coil packs, and other things you didn’t have to do before you changed from diesel.”
“This is just the tip top of the iceberg with CNG. It’s coming big time.”
– Jeffrey Tews, fleet operations manager, for the city of Milwaukee
The cost of a fueling station depends on how much fuel is used and in what timeframe. “If you are filling 300 gallons an hour time, you will pay a lot more than if you are looking to fill a few trucks overnight,” says Tews.
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