January 2008 - Feature
Two NYC Agencies Invest in CNG and Hybrid Power Alternatives
By Art Vatsky, PE
NYC Transit Reaps Hybrid Bus Benefits
NYCT is actually part of the Metropolitan Transportation Authority (MTA) a New York State agency. NYCT is the nation’s largest transit agency with more than 4,500 heavy-duty buses in its fleet. When it comes to hybrid buses, they also were early investors in the technology. Today, the agency is reaping the benefits of its efforts.
If you visit Manhattan, it is hard to find a NYCT bus that is not a hybrid. They operate on both the long uptown/downtown routes as well as the much shorter cross-town routes. By the end of 2007, the agency expected to operated more than 800 hybrids in the metro New York City area.
Cleaner-exhaust CNG sweepers rid NYC of contamination on the streets and in the air.
Obstacles Overcome
Once again, initial operational problems had to be tackled and overcome. That process started in 1996-98, with the agency working with the Orion Bus Company and British Aerospace (BAE), which committed to a series-hybrid design for the New York City buses.
After several prototype models, quantity deliveries began in 2004, followed by 2005, 2006, and 2007-models. Each uses a relatively inexpensive lead acid battery pack that needs periodic charge balancing every six months to maintain optimum performance and battery life. In the future, the buses will be powered by lighter, more efficient lithium ion batteries.
The benefits from this addition to maintenance efforts are several: reduced brake wear due to the regenerative braking that occurs on hybrid bus in urban traffic; reduced brake squealing at each bus stop; reduced wear and tear on the engine; and an approximate 30-percent improvement in fuel economy relative to a conventional bus in similar service. Additionally, series-hybrid buses lack a conventional transmission so those corresponding service needs are eliminated.