Many urban transit systems have been moving to green vehicle technology in recent years. New York, for example, began converting its buses to clean diesel and compressed natural gas back in 2000, and now operates almost 1,200 hybrid electrics, the largest such fleet in the world, according to the Metropolitan Transit Authority.
Yet the transition to low-emission fleets has been hampered by reports of technical problems on hybrid electric buses as well as high price points. Indeed, at a time when local and regional governments are struggling to contain costs, the hybrid premium poses a real challenge for transit officials.
Altair Product Design, a Troy, Michigan-based engineering firm, is aiming to fill the breach with a new type of light-weight hybrid city bus powered mainly by hydraulic pumps. The 26-year-old company, which has designed a broad range of vehicles for the Big Three and many international bus manufacturers, has developed a modified diesel engine that runs a hydraulic motor linked to the wheel shaft. The pumps can capture and reuse about 70 percent of the energy used for breaking.
The technology is widely used in off-road industrial vehicles, says Altair chief operating officer Mike Heskitt. “These things have been around for years.”
Having produced and tested prototypes using federal and state funding, Altair claims its hydraulic hybrids boast gas mileage of about 6.9 miles per gallons, compared to 3.3 mpg for a standard diesel bus. The company will unveil the bus at the American Public Transportation Association’s bus procurement workshop/conference next month in New Orleans.
Altair intends to build the buses from scratch instead of designing them for other manufacturers; a full production facility is at least two years away.
Heskitt says Altair aims to sell its vehicles for $410,000, which is about a third cheaper than current hybrid electrics. But the big savings, he adds, will come with lifetime operating outlays. According to company estimates, its hydraulic buses will cost about $720,000 to maintain over their lifetimes, while hybrid electrics, clean diesel, and compressed natural gas buses tend to be in the $900,000 range. The firm has not yet lined up any transit agency customers.
With about 5,000 city buses purchased each year in the U.S., Heskitt reckons that Altair can carve out a niche with bus-based transit agencies looking for a lower cost way to reduce emissions. “We expect this is going to change the game,” he says.