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Photos Courtesy: Miami-Dade Transit
Springtime in Miami means even warmer weather than it normally enjoys, the sound of construction crews continuing their work on the new AirportLink extension and, it means, customers will get a chance to ride one of five new green-technology buses Miami-Dade Transit
(MDT) has added to its fleet.
These new hybrid buses will join 38 other hybrids in MDT's fleet of more than 800 buses. The transit system also boasts a 22.6-mile heavy rail system (Metrorail), a 4.4-mile downtown light rail system (Metromover), as well as its contracted paratransit service (Special Transportation Service).
MDT Director Harpal S. Kapoor was instrumental in introducing hybrid technology to Miami-Dade County. It was his experience at the Washington Metropolitan Area Transit Authority (WMATA), where he worked as assistant manager of bus engineering, from 1999 to 2006, that led him to champion hybrid buses based on his testing of new propulsion technologies. In 2006, Kapoor was able to gain support from the Miami-Dade County Board of Commissioners to switch MDT's new bus procurements to hybrid technology. MDT also began using a 5 percent biodiesel fuel blend for the entire fleet in 2009.
Continuing its vision for a greener fleet, MDT took delivery of five new Gillig 40-foot low-floor diesel-electric hybrid buses, which were placed into fixed-route service in mid-April. These new hybrids, purchased at a cost of $3.1 million, are expected to deliver 30 percent fuel savings when compared to conventional diesel buses, according to MDT.
In addition to fuel savings, maintenance costs for hybrid vehicles ($0.95 per mile) are significantly lower than diesel vehicle costs ($1.51 per mile).
The new vehicles are equipped with Cummins ISB 280 HP engines that meet 2010 emission standards via SCR exhaust after-treatment and diesel particulate filter technologies, as well as an Allison hybrid-drive system employing regenerative braking.
A key feature of these buses is the beltless alternator, where the bus's electrical system pulls power from the hybrid batteries and, also, operates the electric fan drive.
Air-conditioning systems were also converted to fully electric by feeding power from an independent alternator driven from the engine. MDT has partnered with Allison, Gillig and Vanner to test the possibility of running the entire air-conditioning system from hybrid batteries.
MDT recently was awarded the Thermo King Energy Efficiency Leader Award for its commitment to improving fuel efficiency by electrifying accessories in its diesel-electric hybrid buses.
In an innovative move to improve energy efficiency and reduce operational costs, MDT has become one of the first transit agencies in the nation to electrify bus accessories. This modification is expected to make the buses 25 percent more fuel efficient.
"By electrifying accessories, like the air-conditioning system in our buses, we're not only operating our buses more efficiently, but also demonstrating our long-term commitment to increasing sustainability by improving fuel economy," says Kapoor.
MDT has plans to electrify more components on the bus, such as power steering, doors, air compressors and wheelchair ramps to further reduce fuel consumption, Kapoor says.
In addition to the greening of the bus fleet, MDT has also reduced its carbon footprint by implementing solar power for all bus shelters, and ten Metromover light rail stations are targeted for LED lighting to save energy. The transit system also adheres to an Environmental Management System (EMS) policy it developed, to regulate its "green" actions such as recycling materials in maintenance shops and disposal of hazardous waste.