Engineering Challenges of the Hydrogen Economy

HE TERM “HYDROGEN ECONOMY” is the title of a recent book [Rifkin, 2002], but the concept of using hydrogen as fuel for transportation systems has been advocated by environmentalists and others for at least three decades. There is no universally accepted definition of the “hydrogen economy,” but it is generally viewed as the replacement of the vast majority of petroleum fuels used by transportation vehicles of all kinds (automobiles, trucks, trains, and aircraft) with hydrogen that is burned in internal-combustion engines, external-combustion (jet) engines, or preferably, used in fuel cells to more efficiently generate power for transportation. A November 2001 meeting of 53 business executives, federal and state energy-policy officials, and leaders of universities, environmental organizations, and national laboratories sponsored by the U.S. Department of Energy resulted in the report “A National Vision of America’s Transition to a Hydrogen Economy—To 2030 and Beyond” [DOE, 2001]. This led to an April 2002 “National Hydrogen Energy Roadmap” workshop where 250 representatives from 135 organizations looked into their crystal balls and projected what would be required to achieve a hydrogen economy [DOE, 2002a]. They attempted to define a common set of objectives and the activities by all the participants that are essential to achieve a hydrogen economy. The conclusion was that “Hydrogen has the potential to play a major role in America’s future energy system.” However, it was further concluded that “Before hydrogen can achieve its promise, all stakeholders must work together to overcome an array of technical, economic, and institutional challenges.” This article attempts to clarify and put in perspective these challenges. Why should it take more than a quarter of a century to achieve the hydrogen economy? In little more than a decade, computers have progressed from a laboratory tool for data processing to almost universal acceptance by the public, taking America into the “Information Age” and revolutionizing the way that we do business and work. Then why is it expected to take so long to achieve the hydrogen economy? One can postulate many reasons— such as the difficulty of the technologies involved, the high costs involved, and competition for public funds with other worthy programs (e.g., education, public health, space exploration, fundamental scientific research, national security, etc.). However, perhaps it is more complicated than that. Public acceptance is a key factor. We will review this issue at the end of the article.