What to consider before switching to alternative fuels
Diesel doesn’t look like it’s about to climb down from its perch and you’re thinking of turning your fuel system “green.” Hybrids, biodiesel, propane and compressed natural gas all have their benefits, but aside from purchasing new vehicles, what’s it going to take to replace your existing diesel fleet?
At first glance, hybrid-electric buses seem like an easy way to improve fuel efficiency without swapping fuels. But, getting extra miles per gallon may mean setting up the garage for extra amps, says Ralph Knight. Before receiving the only IC hybrid-electric school bus in California, the transportation director for Napa Valley Unified School District changed his power breakers from 110 volts at 10 amps to 220 volts at 30 amps to enable a four-hour rather than eight-hour charge. The breakers didn’t cost much more than $120, but Knight already had outdoor charging stations left over from when he ran all electric school buses. Other districts will have to think about how they’re going to plug in before they hit the road.
Biodiesel, often promoted as the cheapest and easiest alternative fuel to adopt, demands added consideration, too. Most school buses can run on blends as high as B20 with as little change as extra fuel filters during the first months. Broadened fuel standards (see pg. 14) may bolster this burgeoning bus application. But before making the leap, bus yards need to clean their fuel storage tanks and check fuel quality.
If the two alternative systems that look most like plain old diesel pose these infrastructure challenges, then it should be no surprise that propane and CNG, the two fuels that seem the most alien, require even more forethought.
In some ways, propane is a lot like diesel. For one, it is a petroleum product. It’s currently about 60 percent cheaper than diesel. Still, when the price of diesel goes up, expect propane to follow, according to Eric Bates, sales manager for Ferrellgas’ western region. Also, petroleum is stored as a liquid, so the distribution pumps don’t require compressors.
Gene Holloway, transportation director for Denton Independent School District north of Dallas, says that’s one of the reasons why he chose propane when he started looking at alternative fuels. In 1996, the district paid $96,000 to install an 18,000-gallon tank. In the years that followed, Holloway has purchased more than 100 propane-powered school buses that use nearly 8,000 gallons of fuel each week.
Bates said his company will pay for almost of all the distribution equipment if a district is willing to commit to a minimum three-year contract for five or more buses. A district would have to pay between $1,500 and $3,500 in concrete slabbing, crash posts and electrical wiring. Other fuel providers will likely make similar contractual offers. Without assistance, propane fueling stations range from around $22,000 for a smaller station fit for one or two buses to over $45,000 for larger fleets.
While installation of one of these 30,000-gallon propane pump system takes between five and 10 days, permits can take as much as six weeks. Bates advises districts looking to get into propane to check into permitting requirements as soon as possible. Companies like Ferrellgas or industry group CleanFuel USA can usually guide districts through this paper jungle.
Operators will also have to consider how they plan to educate their employees. While propane pumps like diesel, fuel providers will still have to come out and perform pre-training on how to fill, what to look out for and how to shut down if something goes wrong. Under many contracts, districts will not have to self-repair their pumping facility.
Compressed Natural Gas
Like propane, compressed natural gas (CNG) promises dramatic reductions in emissions. But, because it is not stored as a liquid, CNG demands a more complex means of distribution and delivery.
Enrique Boull’t, transportation director for Los Angeles Unified School District, runs one of the largest CNG fleets in California with more than 173 CNG school buses in a fleet of 1,300. Rather than take deliveries, he gets his CNG piped in from Trillium, a company that fuels 1,750 transit buses per day including all of the Los Angeles and New York City metro CNG fleets.
There are also two kinds of CNG filling stations: slow fill and regular pumps. Because electricity rates for the pumps that compress CNG are cheaper at night, slow fill is a less expensive option. The three- to four-hour filling can also squeeze as much as 20 percent more fuel into a tank compared to a regular speed fill.
CNG requires some safety considerations that diesel does not. Before getting CNG, Boull’t retrofitted his service areas with exhaust and seepage fans. Others add fire protection, gas detection and pilotless heat. Drivers can receive a relatively quick education in fueling, but mechanics will need to be trained in fire safety, tank inspection and emergency shutdown. Just as with propane, fuel providers oftentimes provide this free of charge.
Districts looking to get into CNG will need to do some planning. Boull’t said a failure to coordinate with the city, gas company and electric company caused him delays in setting up a satellite filling station. Before starting a project, he suggests bringing together school facilities managers, project managers, contractors and environmental and electrical specialists to discuss the project from every angle.
While CNG may have a greater initial cost — a fueling station can run from $475,000 to more than $1 million — Stephe Yborra, director of marketing for natural gas industry group NGVAmerica, stresses there are ample opportunities to offset lifetime costs. Tax credits for infrastructure are a drop in the bucket — $30,000 max for the first $100,000 — but both districts and contractors can get a 50-cent per gallon equivalent tax credit, which is also available for propane. Contractors can get credits for vehicles, and both contractors and districts can get grants from their states as well as the U.S. Department of Energy, the U.S. Department of Transportation and the Environmental Protection Agency. Under new EPA rules, the newest CNG buses can get grants to pay for half of the added price difference between CNG buses and diesel buses.
Reprinted from the August 2008 issue of School Transportation News magazine. All rights reserved.