ALTERNATIVE FUELS FOR BUSES * WORLDWIDE
* USA - New Generation of Buses Run on Alternatives Fuels
USA -Green Car, by Bill Siuru -Originally published 23 Oct 2007: -- Following fixed routes and refueling at a central location are characteristics of transit bus operation. These characteristics also happen to provide an ideal application for alternative fuels like natural gas and hydrogen that don't yet enjoy a widespread fueling infrastructure... Most of today's interest in hydrogen is directed at its use in fuel cells. However, it can also be used in internal combustion engines (ICEs) that normally run on gasoline or diesel fuel. An example is presented by ISE Corp., which has worked with SunLine Transit to build the first transit bus in the United States to use a hybrid hydrogen internal combustion engine (HHICE) drive. The ISE ThunderVolt TB40-HICE system has been installed in a 40-foot New Flyer low-floor transit bus. Here, the Siemens generator is driven by a Ford Triton 6.8 liter V-10 engine modified to operate on pure hydrogen. It provides up to 150 kW of electric power in this series hybrid to drive a Siemens ELFA drive system. Excess energy, as well as energy recouped by regenerative braking, is stored in Maxwell ultracapacitors...
The HHICE offers most of the benefits of a hydrogen fuel cell powerplant along with very mature internal combustion engine technology. The HHICE can provide most of the emission reduction benefits of a fuel cell system at a fraction of the cost. Engines operating on hydrogen mean minimal impact on the ICE manufacturing and maintenance infrastructure. Engine manufacturers could build hydrogen ICEs on production lines used for gasoline and diesel engines. In contrast, hydrogen fuel cells will likely require large investments in new facilities and equipment. Also, fuel cell buses will require significant retraining of transit agency maintenance technicians and new equipment... Two California transit agencies, AC Transit in Oakland and the SunLine Transit Agency serving Palm Springs and the Coachella Valley, are operating new 40-foot, Belgian-built Van Hool A330 transit buses. What makes these buses unique is the use of ISE's ThunderVolt TB-40FCH fuel cell hybrid-electric drive system. AC Transit has three of these advanced alternative fuel buses, while SunLine has one. This drive system uses a 120 kW PEM (proton exchange membrane) fuel cell supplied by UTC Power. Hydrogen fuel is stored at 5000 psi in eight aluminum-lined, carbon fiber-wrapped tanks located on the roof. Electric energy is stored in ZEBRA 650 volt nickel sodium chloride (NaCl) batteries. Energy from the fuel cell and batteries is delivered to dual Siemens 85 kW traction motors via a Siemens ELFA drive system...
Canada's New Flyer Industries in Winnipeg, Manitoba, is building the world's first fleet of hydrogen fuel cell buses for BC Transit. The new fleet of 20 buses, slated to be delivered by late 2009, will initially be based in Whistler, B.C., for use during the 2010 Winter Olympics. The 40-foot, low-floor buses will feature fuel cells supplied by Ballard Power Systems and use an ISE hybrid drive system... For hydrogen to be a truly renewable fuel it must ultimately be made in sustainable ways, such as electrolyzing hydrogen from water using solar- or wind-generated electricity. An example of this comes from ISE Corp., which has completed a wind-powered hydrogen generation plant in Palm Springs, Calif., where SunLine Transit can refuel its hydrogen buses. This makes SunLine the first transit agency to use a completely renewable fuel with virtually no pollution created at any stage of its production or use. Each Nordtank wind-powered turbine operated by Palm Springs' Wintec Energy generates sufficient electricity annually to produce enough hydrogen to power a bus for about 30,000 miles...
OTHER ALTERNATIVES
If hybrid and hydrogen powerplants are the "glamour" technologies, then buses with engines running on alternative fuels like compressed natural gas (CNG) and liquefied natural gas (LNG) are clearly today's clean-fuel workhorses. Natural gas is used extensively in transit since it's much cleaner compared to diesel and offers a better near-term value proposition. According to NGVAmerica, there are about 10,000 natural gas transit buses operating with 125 transit agencies. This represents some 12 percent of all transit buses in service. This trend is continuing, with 20 to 25 percent of all transit buses on order running on natural gas... The 200 sleek Metro Liners in service with Los Angeles Metro illustrate how today's readily-available powerplant technologies and fuels needn't look old school. These Metro Liners are typical of the futuristic styling that's becoming the norm in new transit buses today, with sleek aerodynamic styling, a huge one-piece windshield, and equally-large side windows. L.A. Metro's 60-foot articulated Rapid Transit buses were built by North America Bus Industries and are powered by 320 horsepower Cummins Westport L Gas Plus engines running on CNG...
The green transit field is evolving even as this is being written. Hybrid-electric transit buses have proven themselves under real-world operating conditions and will be used by a growing number of transit agencies. Widespread use of fuel-cells buses may be 10 to 20 years in the future, mainly because of their high cost and lack of refueling infrastructure. Hydrogen internal combustion-engine buses, which are much less expensive, could help create near-term demand for hydrogen that will lead to an expanding hydrogen fueling infrastructure... Natural gas is a logical choice for agencies that want substantially cleaner and more affordable operation today but aren't interested or willing to invest in the high cost of more advanced or exotic technologies. And what about electric buses? Many industry experts say pure battery-powered buses are not viable for most transit applications ... but we'll have to see how battery development unfolds in the years ahead to weigh in on that one...
posted by Unknown @ 7:32 AM
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