From Hybrid Batteries to old Bus Windows Efficiency is in High Gear at NYC Transit

MTA New York City Transit’s Department of Buses has long been on the road to greening its operation through the incorporation of sustainable technology. Aside from the vital fact that NYC Transit’s fleet of 4,500 buses removes an estimated 180,000 cars from area streets and highways, the agency has been at the developmental forefront of technologies and practices intended to make municipal bus transportation as ecologically benign as possible.

Most visible to the customer is our agency’s fleet of Hybrid-Electric buses.  In fact, NYC Transit has been a leader in the introduction and development of this technology.   Currently, more than 800 hybrid buses are operating on New York City streets with a similar number on order and set for delivery.  The exhaust profile of these buses is, on average, 30 percent cleaner than their conventional diesel counterparts, and hybrids have also proven to be more fuel efficient with a clear advantage in the stop-and-go driving that typifies New York City Transit bus operations.

While the hybrids are common sights on the streets these days, the technology is still advancing, particularly in the area of storage batteries.  The Department of Buses is currently testing a quartet of Orion Hybrid/Electrics with a lithium-ion battery array in place of the lead-acid batteries.  We are looking at a number of advantages with the lithium batteries, including a longer life-span, the ability to capture more of the braking energy from the bus, while also eliminating the need to periodically maintain the batteries.

Another benefit of the new battery array is lighter weight, trimming about 3,200 pounds off the 4,000 pound weight of the lead-acid batteries.  From the start of hybrid-electric bus development project we knew that there would be technological improvements and advancements to the storage battery systems and we have been looking forward to testing and implementing them.

In another move to increase the efficiency of the hybrids, the Department of Buses has changed the propulsion management software to dial back the acceleration rate so that the bus consumes less fuel.  As oil prices climb higher this becomes even more important.

In the push to create new efficiencies, we are even seeking ways to make our tires more efficient.  Buses assigned to three depots in Brooklyn are now riding on tires filled with nitrogen as part of a pilot program to determine its effectiveness.  Nitrogen-filled tires are said to maintain pressure longer than air filled tires, which cuts maintenance time as tires do not have to be checked and filled as often.  It is also projected that they will last longer than air-filled tires.

Of course, in an agency as large as New York City Transit, we look for improvements in all areas, including the recycling of usable parts culled from buses that are being retired. Department of Buses Senior Vice President Joseph Smith has taken a hard look at how his department disposes of items and when it makes sense not to get rid of them.  In the past we had been scrapping our buses intact, but that makes little sense when we are still operating similar vehicles.  An item as simple as bus window costs upwards of $900.00 apiece.  What we are doing now is removing the windows from scrap buses and reusing them when needed.

Of course, the ultimate recycling effort involves updating bus components to keep the vehicle in service as long as possible.  While Hybrid-Electrics are a growing segment of the fleet, most NYC Transit buses are still powered by standard diesel engines.  Recognizing, however, that diesel engine and clean emissions technology is advancing, the Department of Buses several years ago developed an innovative program that continues to pay benefits.

In 2002, the agency began to re-power more than 650 older RTS and Orion buses, replacing their two-stroke diesel engines with new, electronically-controlled four-stroke engines and combining them with advanced exhaust-treatment devices.  This move has had the double effect of contributing to clean air in the region while also prolonging the lives of vehicles that would have been scrapped.  This engine swap was even more effective as NYC Transit became the first large transit agency to power its bus fleet with ultra-low sulfur diesel fuel.

Efficiency advancements have also been in areas that are largely out of sight of our customers.  Since 1993, the Department of Buses has been partnering with the New York Power Authority on a series of progressively more comprehensive projects to improve the energy efficiency of our facilities and operations.  Our depot facilities are benefiting from projects that include upgrades to energy efficient lighting, boilers, compressors, fan motors and the installation of rapid roll-up doors.  These projects are financed through the savings in energy bills.

With most of the “easy” changes having been made, we have begun looking at other segments of our operation, seeking to make improvements in areas that, while out of the public eye, are no less beneficial than earlier changes.  As a result, a major program is underway to design efficiencies into new facilities, reduce the use of metered water and increase the recycling effort focusing on everything from paper to, well, retired buses.

New York City Transit is in a leadership position in the area of improving the environment, but as we look more deeply into our operations we see that we can do even more to increase our sustainability efforts.  Unlike new buses with advanced propulsion systems and cleaner exhausts, the changes we are currently making cannot necessarily be seen by the riding public, but the environmental benefits will be measurable.

An example of this design philosophy is the new Grand Avenue Bus Depot and Maintenance Facility.  Opened in November, 2007, the two-story 560,000 square-foot facility, like all new NYC Transit buildings was designed to take advantage of high-performance technologies that work to reduce energy consumption and operational costs.

The building design includes energy-efficient lighting, high-performance window glazing, increased use of natural lighting and ventilation.  Another major feature is a system that captures rainwater for bus washing and other non potable uses.  This system is supported by below grade tanks for rainwater storage.  Located beneath the first-floor, the system collects rainwater run-off, which is then used for non-potable purposes.  This reclamation system captures 85% of the water necessary for bus washing.

A large part of our Green Initiative involves the recycling of fluids, metals, paper materials and construction debris.  Items that previously would have just been tossed out, eventually finding their way to a landfill, are now recycled.

Guided by a responsibility to the environment and the need to make more efficient use of funding, the Department of Buses has looked hard to make improvements across the spectrum of its operation.  Finding savings in areas as diverse as new battery technology and the recycling of rainwater is impressive, but rest assured we won’t stop there.