Why keep living the hydrogen fuel cell dream?
Auto makers favour fuel cells for two main reasons: no need for petroleum and no emissions from the tailpipe. A fuel cell uses hydrogen to generate electricity through a chemical reaction and emits only water vapour through the tailpipe. Hydrogen is plentiful and can be derived from natural gas, methanol and even water.
Compared to other so-called "green" transportation technologies - gasoline-electric hybrids, plug-in hybrids and battery-powered vehicles - hydrogen fuel cell-powered vehicles could be a promising way for car companies to meet stiffer CO2 regulations later this decade.
So what's in a fuel-cell powertrain? Four main elements:
1. A tank that stores hydrogen.
2. A fuel-cell stack that converts hydrogen and oxygen into heat and water, creating electricity.
3. Lithium-ion batteries that store the electricity.
4. A power unit that controls the flow of electricity to the electric motors that propel the vehicle.
Unlike a battery-powered vehicle that can take six, seven, eight or more hours to recharge, a hydrogen refill takes about 3.5 minutes. Battery-powered cars generally have a range of no more than 160 km, yet Honda's Clarity fuel-cell sedan can travel about 400 km on hydrogen.
Battery cars and hybrids aside, auto makers say electric vehicles powered by fuel cells compare well against internal combustion engines with catalytic converters. According to General Motors, fuel-cell-powered cars are more than twice as efficient as internal combustion vehicles. Moreover, fuel cell cars boast:
• Comparable precious-metal content
• Comparable durability
• Comparable range: about 400-500 km or more
• Comparable performance
• 60 per cent fewer parts
• 90 per cent fewer moving parts
• Zero emissions
• Zero petroleum needs
• Cold and hot weather capability
• Fast refuelling