A new model of hybrid electric bus was previewed by area shuttle service providers Wednesday.
By: Steve Rauscher
It is powered by a turbine engine, but it redlines approaching 40 miles per hour.
What is it?
It’s a new model of hybrid electric bus that area shuttle service providers sneaked into service Wednesday.
"This is so people can try out electric buses and see that some of the myths about them are just that: myths," executive director of the Mercer County Transportation Management Association Sandra Brillhart said. "People think that they can’t go very far, and it’s just not true anymore."
The TMA worked in conjunction with the East Coast Hybrid Consortium and A-1 Limousine Co. on Wednesday to showcase the hybrid bus. On that day it replaced A-1’s diesel shuttle buses between the Princeton Junction train station and the Merrill Lynch complex on Roszel Road in West Windsor. The bus, an AVS-22, manufactured by Advanced Vehicle Systems in Chattanooga, Tenn., completed the roughly 1-mile round trip seven times in about four minutes per leg, Ms. Brillhart said.
While the AVS-22 is a hybrid, it is powered differently from the hybrid cars one sees on the road from time to time, AVS engineer Kirk Shore said. Those cars, such as the Toyota Prius and the Honda Insight, have both a gasoline-powered engine and an electric motor. The gas motor provides power during acceleration and at higher speeds, while the electric motor provides power at lower speeds. The electric motor’s batteries are then partly recharged during braking.
The AVS-22, on the other hand, is propelled exclusively by an electric motor, powered by a battery that is recharged by a small turbine engine about the size of a beer keg, Mr. Shore said. Once the electric engine has drawn down the battery’s capacity to 60 percent, the turbine engine kicks in, turning a generator and providing a fresh flow of energy. The turbine in the AVS-22 in use Wednesday runs on diesel fuel, Mr. Shore said, but because the turbine is capable of operating at very high temperatures it can run on renewable fuel sources such as vegetable oil.
"It’ll run on French fry grease if you want it to," he said. "It’ll run on just about anything that burns."
Because the combustion of diesel fuel is at such a high temperature, about 1,100 degrees, about 98 percent of the fuel is consumed, Mr. Shore said. The ultra-low emission bus has a fuel efficiency of about 5 to 10 miles per gallon. A diesel internal combustion engine, by contrast, achieves combustion temperatures of about 300 to 400 degrees, and provides a similar vehicle about 2 to 5 miles per gallon. Electric engines, he said, are also extraordinarily quiet.
"I would think this is something we’re looking at as a viable alternative in the very near future," Ms. Brillhart said. "We’d like to see some service providers actually purchase these buses and put them to use."
But low emissions and quiet come at a very high price. Jeffrey Starr, senior vice president at A-1 Limousine, said the diesel buses his company runs on the train station route cost $75,000 to $125,000. The AVS-22 costs $250,000, and Mr. Starr said that, while his company is committed to "putting a cleaner vehicle on the road," the AVS-22 may not be the answer.
The high cost, he allowed, was partially a function of the low-production run at Advanced Vehicle Systems. Because of the lack of demand for the vehicle, the company is unable to take advantage of the economies of scale available to companies with higher output.
"The trick here is that, to sell more buses, they need to charge a lower price. But, to charge a lower price, they need to sell more buses," he said.
The AVS-22, with a top speed of 40 mph, also lacks the versatility that would make its purchase economical, he said. A bus that can’t go on the highway is of limited use.
A-1 Limousine may turn to federal and state government transportation agencies in order to secure funding to purchase the vehicles, Mr. Starr said.
"That would help a lot, no doubt about it," he said.
Until then, Mr. Starr said, the diesel buses his company uses now are relatively new and contain technology that allows them to operate at 95 to 98 percent efficiency.
"That’s not zero-emissions," he said, "but it’s not bad."