Thursday, July 29, 2004
Zero-Emission Hydrogen Vehicle Risks
[http://216.239.41.104/search?q=cache:tZ748JNUsrYJ:www.slnett.no/digimaker/documents/Sikkerhetsrapport_hydrogen_Veritas_pozDOB80as.pdf+hydrogen+powered+bus+dangers&hl=en] Safety Assessment of Hydrogen Buses (link no longer valid)
Safety issues regarding fuel cell vehicles and hydrogen fueled vehicles
"The two prime dangers from fuel cell and hydrogen-powered vehicles are the danger of electrical shock and the flammability of the fuel....
"The fact that over 350V are needed for the drive train of fuel cell vehicles presents both an electrocution hazard and an ignition source for fuel contained in the vehicle or outside materials. Since a significant amount of the material used in vehicular construction is metal, with some degree of electrical conductivity, there is a high potential for electrical faults. This can pose a threat both in normal operations of the vehicle and especially in accidents. Even though most designs contain failsafe switches for the electrical system, these switches may be short-circuited if the vehicle is involved in an accident.
"In addition to the electric current generated by the fuel cell during its operation, most prototype vehicles have an electrical storage component for acceleration and start up, much like today’s hybrid vehicles. Most fuel cell vehicle store and draw on this additional electricity in form of batteries. Batteries can also represent the additional danger brought on by the presence of acids, to both the electrical system and the fuel system. More exotic and less researched forms of energy storage are ultra capacitors and mechanical flywheels. Ultra capacitors store electrical energy under high voltages for rapid release. While this is positive for vehicle operation, it also holds the risk of very strong unintentional electrical discharges."
Hydrogen Powered Vehicles
"The fuel cells fit into the space that normally holds the bus' diesel motor. The price of the bus, however, is $1.1 million ... four times the cost of a standard diesel bus."
California adopts new emission standards for urban buses
"From model year 2008 through 2015, large transit agencies on the "diesel path" will be required to make ZEBs 15% of their new bus purchases/leases. For large transit agencies on "alternative fuels path", the 15% ZEB rule runs from model year 2010 through 2015.
"The new bus emission rule was criticized by the natural gas industry, which expected that the ARB would mandate wider use of alternative fueled buses. Clean diesel technologies, which are allowed for transit agencies that choose the "diesel path", have the potential of achieving emission levels comparable to or cleaner than those from natural gas engines without the high costs of switching to and operating alternative fueled vehicles."
Operations Update July/August 2004
"Under its 2000 Clean Fuels Strategy, VTA will transition from low sulfur diesel technology to Fuel Cell technology as soon as possible."
Once again, VTA demonstrates a total lack of concern for costs. And despite the tall talk about safety being its top concern, completely discounts the catastrophic risks involved in hydrogen fuel cell technology.
- Low viscosity (i.e. leaks easily).
- Odourless, colourless, tasteless and non-toxic gas (like methane and propane).
- Highly flammable with a low ignition energy (electric loading like friction and static electricity can cause ignition).
- Burns with a nonluminous (low-visibility) flame, and a faster flame speed than other fuels (if the concentration is not very lean or very rich).
- Explosive over a wide gas concentration range (4 % to 74 % by volume). Hydrogen can detonate over a very wide concentration range when confined.
Safety issues regarding fuel cell vehicles and hydrogen fueled vehicles
"The two prime dangers from fuel cell and hydrogen-powered vehicles are the danger of electrical shock and the flammability of the fuel....
"The fact that over 350V are needed for the drive train of fuel cell vehicles presents both an electrocution hazard and an ignition source for fuel contained in the vehicle or outside materials. Since a significant amount of the material used in vehicular construction is metal, with some degree of electrical conductivity, there is a high potential for electrical faults. This can pose a threat both in normal operations of the vehicle and especially in accidents. Even though most designs contain failsafe switches for the electrical system, these switches may be short-circuited if the vehicle is involved in an accident.
"In addition to the electric current generated by the fuel cell during its operation, most prototype vehicles have an electrical storage component for acceleration and start up, much like today’s hybrid vehicles. Most fuel cell vehicle store and draw on this additional electricity in form of batteries. Batteries can also represent the additional danger brought on by the presence of acids, to both the electrical system and the fuel system. More exotic and less researched forms of energy storage are ultra capacitors and mechanical flywheels. Ultra capacitors store electrical energy under high voltages for rapid release. While this is positive for vehicle operation, it also holds the risk of very strong unintentional electrical discharges."
Hydrogen Powered Vehicles
"The fuel cells fit into the space that normally holds the bus' diesel motor. The price of the bus, however, is $1.1 million ... four times the cost of a standard diesel bus."
California adopts new emission standards for urban buses
"From model year 2008 through 2015, large transit agencies on the "diesel path" will be required to make ZEBs 15% of their new bus purchases/leases. For large transit agencies on "alternative fuels path", the 15% ZEB rule runs from model year 2010 through 2015.
"The new bus emission rule was criticized by the natural gas industry, which expected that the ARB would mandate wider use of alternative fueled buses. Clean diesel technologies, which are allowed for transit agencies that choose the "diesel path", have the potential of achieving emission levels comparable to or cleaner than those from natural gas engines without the high costs of switching to and operating alternative fueled vehicles."
Operations Update July/August 2004
"Under its 2000 Clean Fuels Strategy, VTA will transition from low sulfur diesel technology to Fuel Cell technology as soon as possible."
Once again, VTA demonstrates a total lack of concern for costs. And despite the tall talk about safety being its top concern, completely discounts the catastrophic risks involved in hydrogen fuel cell technology.
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