11/27/2011 | STEPHEN MURPHY Editor-in-Chief
More than 70 percent of all school buses use diesel fuel, raising questions about what the impact is, not only on the environment, but also on children’s health. Funding realities often necessitate buses being kept in service well past their expiration date — even up to 20 years or more — beyond the time when these buses adhere to the minimum safety standards. Buses built before 1990 and 1991, which are still on the road, are allowed to emit six times more toxic soot and three times more smog-forming nitrogen oxides than newer models, exposing children to greater levels of air pollution. But even the cleanest running diesel bus on the road today releases about five times more soot and twice the amount of smog-forming pollutants as, for example, a natural gas bus.
New school buses provide a number of significant health and environmental advantages over older school buses. Schools are looking for ways to safely and economically replace or retrofit these old school buses with new, cleaner running models.
Alternatives to Diesel
Hybrid electric school buses are another option under consideration. The Kentucky Department of Education is in the midst of a project that introduces 213 hybrid school buses throughout the state, which will be the largest hybrid electric school bus fleet in the United States. In August 2009, the U.S. Department of Energy awarded $13 million to the Kentucky Department of Education to cover the incremental costs of hybrid buses over traditional diesel buses, which will lead to significant reductions in petroleum consumption. Manufacturers estimate fuel savings will be as high as 40 percent, with increases in fuel mileage from 7.5 to 12 miles per gallon, relative to standard diesel buses.
According to Kentucky Education Commissioner Terry Holliday, “The hybrid school bus project not only serves as a means to improve efficiency and be environmentally conscious but this project will also provide students with learning opportunities across many subject areas. Teachers can develop lesson plans related to fuel consumption, air quality, and transportation costs, bringing real-world knowledge and hands-on experiences into the classroom.”
However, hybrids do come with by far the largest price tag. Without a sizable grant, many school districts do not have the funds required to purchase just one bus.
There have been advances in natural gas engine and vehicle technology over the past 10 years that have leveled the playing field compared with their gasoline and diesel counterparts when it comes to durability, performance and reliability. School buses that use natural gas come with significant emission reduction compared to diesel.
Despite natural gas vehicles’ good points, many school districts have been slow to adopt using them en masse, often due to higher infrastructure costs. As schools deal with across-the-board budget cuts, their transportation budgets often fall low on the priority list. Districts are being told to do more with less so schools are looking to find affordable ways to address their transportation needs.
More and more school districts are turning to propane as a viable alternative. The Gloucester County, Virginia Public Schools recently launched the state’s first propane school bus fleet.
“Using propane-powered school buses is a step in the right direction to significantly decrease vehicle emissions and improve the air quality for our students,” says Roger Kelly, director of transportation for Gloucester County Public Schools. “We are excited to be involved in this clean school bus initiative.”
“We are pleased and impressed with the forward thinking and actions of the Gloucester County School Board and administration,” says Chelsea Jenkins, director of Virginia Clean Cities. “The propane school buses are providing opportunities for students and the community to observe and learn first-hand about alternative transportation technologies.”
Propane is a clean burning fuel, so it causes less wear and tear on bus engines and components, thus reducing maintenance costs and increasing bus up-time. This factor is widely reported by school districts that currently use propane technology and it can increase the lifespan of each school bus. Given the high cost of new school buses, longevity must be a major factor in districts’ buying decisions.
Propane is an established fuel and established technology; worldwide over 15 million vehicles operate on propane. It is also a highly affordable technology, especially in light of the 50-cent per gallon tax rebate that accompanies propane purchase. Acquisition costs are reasonable; propane school bus technology is only a few thousand more than a comparable diesel bus. This offers a rapid return on investment while eliminating a lot of the health concerns surrounding diesel buses.
Texas’s Denton Independent School District has been using Blue Bird’s Propane-Powered Vision since 2007. According to Gene Holloway, Denton’s Director of Transportation, “...propane-powered buses ... offer greater power, operate quieter and the emissions are safer for the children we transport.” In addition, the incentives and tax rebates have allowed the school district to save money on their transportation budget.
Propane is currently around $1.80 per gallon when purchased in bulk, so with the 50 cent rebate factored in, propane comes to only $1.30 per gallon. Propane infrastructure is affordable and many times a propane provider will provide the infrastructure at no additional charge when there is a provider contract in place.
“Propane autogas is the right choice for school districts, offering the safest and most economical transportation choice for schools across America,” says Joe Thompson, President of ROUSH CleanTech.