Hydrogen: A Future Energy Carrier?

The world has a voracious appetite for energy. Abundant, inexpensive resources have fueled technological advances from the Industrial Revolution to the present. Continued growth will require a continued supply of inexpensive energy that is not sustainable with current resources. In addition, concerns about greenhouse-gas emissions from fossil-fuel sources are generating a new set of technological requirements. In the ideal, albeit distant, future is a world of renewable, pollution-free energy sources for everything from electrical power grids to personal vehicles. The path to that future is, technologically speaking, a steep uphill climb. Hydrogen is likely to be a part of this idealistic future, and possibly an important part. A hydrogen molecule [H2] in the presence of oxygen can be converted to water with a release of heat and work. It is difficult to imagine a cleaner source of energy. However, there are challenges. To begin with, molecular hydrogen does not occur naturally in high concentrations; it is only 0.00005% of the air. Hydrogen is normally bound in other molecules, water and hydrocarbons being the most common. Unlike natural gas, molecular hydrogen is not found in large accumulations in geologic strata, either. This means that hydrogen is not a primary fuel source. Like electricity, it is a means for transmitting energy from primary fuel sources to users. Like electrical power, hydrogen must be produced and transported, although hydrogen has an additional attribute that makes it more attractive for some applications than electricity: it can be stored for later use. This feature makes it useful for powering vehicles and other portable devices. Current production of hydrogen is about 50 Mt/yr [55 million US tons/yr], mostly for industrial purposes in chemical and petrochemical applications. A world economy using hydrogen as a major energy carrier will require a tremendous increase in that volume, as well as a complex new infrastructure for transporting and delivering hydrogen to end users. This article discusses the global transition to a hydrogen economy and the roles oil and gas industry sectors might play over the next decades. Also described are some of the major technological barriers that must be overcome.