“Hybrid electric school buses are helping our school districts save money while reducing energy use and cleaning our air,” Wisconsin Governor Jim Doyle said for a ribbon-cutting ceremony for a solar-energy powered bus canopy earlier this year.
That solar fueling station in Oconomowoc, Wis. is generating electricity, used to charge 11 plug-in hybrid electric vehicle (PHEV) school buses. The buses, put into service at the beginning of the 2010 school year, are serving Wisconsin school districts – helping them save money and reduce greenhouse gas emissions.
“To the casual observer, the outside of the bus is the same. For folks just driving down the road, you wouldn’t see a difference,” says Sandy Syburg, president of Oconomowoc Transport Company (OTC) in Oconomowoc, Wis., which owns and operates the school buses.
Syburg says that the 224 solar panels atop the OTC bus canopy are estimated to generate more than 60,000 kWh per year—enough to keep the PHEV batteries charged, or power six American homes for a full year.
Recovery Act and local business
The PHEV school buses are supported by $3.6 million from the Wisconsin Clean Transportation Program, which is one of 25 projects supported by the Recovery Act-funded Clean Cities Alternative Fuel Pilot Program.
The state will soon be home to 24 PHEV schools buses run by two Wisconsin-based companies – Oconomowoc Transport Co in Oconomowoc and Riteway Bus Service in Oak Creek.
What’s more, the solar fueling system was installed by yet another Wisconsin company -- the neighboring Waukesha-based Renewable Energy Solutions. The panels were manufactured in Memphis, Tennessee.
A growing fleet means a greener Wisconsin
Even though the buses only operate 178 days a calendar year, the 11 PHEV buses will save the Oconomowoc school district nearly 7,500 gallons of fuel each school year.
A typical diesel bus gets around seven miles per gallon, says Syburg. These buses will get 12.
“The buses just rolled out on September 1, so we’re still in the process of quantifying savings,” says Syburg.
Manufacturers say the buses could get up to 50 percent better fuel efficiency compared to a standard diesel bus. The buses will also reduce greenhouse gas emissions by anywhere from 30 to 40 percent.
On the road
These electric hybrid technology works best with a stop-and-go driving technique, says Syburg.
In addition to the charge gained from the solar array, the buses also recharge their batteries using regenerative braking, just like traditional hybrid vehicles. The school bus—with the need to stop frequently to pick up students—is an optimal candidate for this technology.
Each bus runs two routes in the morning and two in the afternoon. Syburg says the selected routes were calculated based on the lowest average speed and highest number of stops.
“Our daily operational fleet is 43 buses. Eleven of those are hybrids, which means 25 percent of our fleet is this new technology,” says Syburg.