Fuel-cell commercialization

The technology race is on to market the next revolution in automotive propulsion, with the first vehicles in limited quantities coming from Toyota and Honda by the end of the year.

The world's automakers have made quite a rumbling about plans for their fuel-cell-powered vehicle offerings, especially so within the past few months. Though most industry experts don't expect any meaningful production volumes for consumer consumption until the 2010-2020 time frame, automakers are steaming ahead with their prototype development and initial limited-production trials and marketing efforts. The fuel cell is considered the most promising long-term automotive alternative drive option, operating very efficiently while producing little or no vehicle emissions if fueled directly by hydrogen. The only waste products generated are heat and pure water vapor. However, the more environmentally friendly hydrogen-delivery options are generally more costly to implement in terms of infrastructure, so automakers are considering a number of fueling solutions. There are six major contenders, according to Bernard Robertson, Senior Vice President - Engineering Technologies & Regulatory Affairs, DaimlerChrysler Corp., who spoke in June at the parent company's Innovation Symposium held in Sindelfingen, Germany, for the media and analyst communities. He presented an overview of each option, based on company engineers' extensive firsthand knowledge of most of them-liquefied hydrogen (in the DaimlerChrysler NECAR 4), compressed hydrogen (NECAR 4a), methanol (NECAR 5 and Jeep Commander 2), gasoline reformation (Commander), metal hydride, and sodium borohydride (Chrysler Natrium).

Liquefied hydrogen-The energy required for cooling the liquid in cryogenic tanks to −253°C (−424°F) has a negative impact on the efficiency of the liquefied hydrogen fuel cycle, as does the “boiling off required to prevent excessive temperatures. The cost of cryogenic tanks is also a major disadvantage. In addition to sophisticated onboard cooling equipment, use of liquefied hydrogen would also require a new distribution infrastructure.