If the hydrogen economy is going to provide the United States with a future free of pollution and dependence on foreign oil, it must be sustainable. That is, it must be able to keep up with increased population growth, increased use of energy-hungry technology, changes in politics and changes in people's attitudes toward the environment and toward the welfare of future generations. It has been estimated that worldwide energy needs will double by the year 2050. It's unlikely that the rapidly diminishing supplies of fossil fuels could keep up with this demand, so new energy resources will be crucial.
One of the chief obstacles to a sustainable hydrogen economy is that the methods currently used to extract hydrogen from larger molecules rely on electricity -- and that electricity is generated largely by methods that create pollution. If hydrogen extraction is performed using electricity from a coal-driven power plant, it doesn't matter that the fuel cell doesn't pollute because the pollution occurred when the hydrogen was extracted. If hydrogen is to be a true nonpolluting power source, the electricity used to extract the hydrogen will need to be produced by a nonpolluting method such as solar power. At present this usually isn't the case, so a truly sustainable hydrogen economy will require substantial changes in power generation.
Storage is also a problem. Hydrogen fuel is stored in compressed liquid form and over time some of it escapes through evaporation. If a hydrogen car isn't driven on a regular basis, the evaporation losses will considerably increase the overall expense of the fuel. And compressing liquid hydrogen to a volume that can be carried in a car also requires a great deal of energy, and that energy may have been generated using methods that cause pollution.
Some experts believe that improvements in hydrogen production and storage will lead to a sustainable hydrogen economy in 15 to 30 years. However, the idea of a hydrogen economy has its opponents, many of whom believe that such an economy can never be sustainable and that our resources would be better used exploring other forms of power generation. It may be years before it becomes clear whether hydrogen is truly the fuel of the future.
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