With substantial investments, hydrogen could become a competitive fuel within 15 years, but the fastest way to reduce carbon emissions from vehicles will be to pursue a wider “portfolio” of new technologies, a panel of experts asserts.
Once hydrogen becomes competitive, it could virtually displace gasoline by mid-century, and related carbon dioxide emissions in the United States would be down to 20 percent of current levels, says the National Research Council study, released on July 17. “You could potentially, in the best case, eliminate all oil from U.S. transportation, and most of the carbon dioxide emissions,” said Michael P. Ramage, who was the executive vice president of ExxonMobil Research and Engineering Co. and chaired the National Academy of Sciences National Research Council panel. He spoke during a press briefing announcing the study.
Meanwhile, for the next 15 to 20 years, hydrogen will have little impact on reducing carbon-dioxide emissions. Until then, the panel says, carbon-dioxide emissions should be kept in check by a multi-pronged approach, which would include hybrid cars, biofuels, and increased fuel efficiency of gasoline-powered vehicles.
Carbon dioxide is a major contributor to the greenhouse effect, which scientists say is the main cause of global warming. Hydrogen-fueled cars only emit water vapor, although some carbon dioxide may be released in the energy-intensive process of producing the hydrogen fuel.
The NRC study focused on cars, light trucks, and SUVs, which together account for about 20 percent of America’s carbon dioxide emissions, according to NAS. It responded to a congressional mandate to determine whether switching from gasoline to hydrogen would be technically and financially feasible on a national scale.
The 17 experts — from private organizations and research institutions — compared the costs and carbon emissions involved with the use of different technologies, including hydrogen fuel cells, biofuels such as ethanol, and simply improving the efficiency of gasoline-powered vehicles.
Hydrogen would be most efficient when used in fuel cells, which extract energy via a chemical reaction rather than by combustion. But fuel cells are still very expensive and distributing hydrogen to consumers would require new infrastructure. Consequently, a large-scale transition to hydrogen will require help from the federal government. “There needs to be durable, substantial, sustainable government effort to make this happen,” Ramage said.
At the same time, economies of scale and technological improvements are likely to bring the cost of fuel cells down. In 10 years, the hydrogen vehicles will be commercially available, if still expensive. At that stage, the government would need to step in with subsidies. By 2023, the study concluded, hydrogen-burning fuel cells will compete with internal combustion engines.
The panel’s scenario is admittedly optimistic. It assumes that the government will invest $55 billion between now and 2023, and that private industry will invest $145 billion over the same time period. It also assumes that the government will impose a tax on carbon dioxide, which would encourage low-emission production of hydrogen for the fuel cells.