'Hybrid and plug-in hybrid petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions' May I add 'extended range electric vehicles' with less than 15 kWh battery packs and low-cost range extenders to the above list with the proviso that battery costs could fall during the next 10 years that will favour range extended vehicles even more. Laszlo

Carcrazy Five thousand hours of fuel cell operating life will do for 1 million miles. The cell works for short periods of time during each trip, charging the battery at 300 kW rate, that is 5000x300=1500000 kWh of charge. If the truck consumption is around 1500 Wh/mile or 1.5 kWh per mile, 1500000/1.5= 1 million miles. The very high cost of the infrastructure per vehicle in operation is going to be more of a problem.