Hydrogen (H), the simplest, lightest and most abundant chemical element, is the main fuel for the nuclear fusion reactions which power the sun. Intensive research is under way to harness fusion energy but hydrogen also shows considerable promise as a potential replacement for conventional fuels.

At normal temperatures and pressures, molecular hydrogen is a tasteless, odourless, colourless gas in which 2 atoms are combined as a diatomic molecule, H2. It has substantial energy content, reacting readily with oxygen to give pure water and heat as the only products. Using hydrogen as a fuel eliminates the pollution caused by burning conventional hydrocarbons. Hydrogen can be manufactured from a wide variety of renewable and nonrenewable energy sources; however, compared to other fuels, it is still very expensive and difficult to produce, store and transport.

In Canada, most molecular hydrogen is produced by the reaction, at high temperature and pressure, of steam with methane (natural gas). Hydrogen also can be produced by applying energy (electricity, heat, solar energy, or some combination) to split water into hydrogen and oxygen. Hydrogen is now used in a wide variety of chemical processes and some scientists and energy planners expect it will become an important fuel for transportation and other applications.

The International Energy Agency maintains an active program of research and development on the production of hydrogen from water, to which Canada is a contributor. In its 1981 report "Energy Alternatives," the House of Commons' Special Committee on Alternative Energy and Oil Substitution recommended that Canada make major investments to establish a leading position in hydrogen technology and systems.

In its Oct 1981 report, the Ontario government's Hydrogen Energy Task Force reached similar conclusions. In 1985, the federal government commissioned a report from the federal Advisory Group on Hydrogen Opportunities. The report, entitled Hydrogen - National Mission for Canada (June 1987), predicted that the world will move over the next several decades to the major use of hydrogen, first in upgrading fossil fuels such as oil sands and coal, and later as an environmentally clean energy commodity in its own right.

A unique opportunity was identified for Canada in leading development of the required technology. An important initiative in this respect has been formation of the Montréal-based Hydrogen Industry Council (1982), which reflects the interests of approximately 50 industrial members.

Applications

Alberta and Saskatchewan have rich deposits of bitumen in oil sands and heavy oils, which could satisfy Canadian energy needs for generations. The key to producing pipeline-quality fuel from these resources is to increase their hydrogen-to-carbon ratio. In processing plants now in operation, this increase is achieved by coking to reduce the carbon content, but the trend in future could be towards hydrogen addition, to extend the hydrocarbon resource. Similarly, hydrogen could be used to produce methanol from biomass: for example, with hydrogen addition, the dry wood required to produce 1000 t of methanol can be reduced from 2300 t to 900 t.

The substitution of hydrogen for gasoline and other hydrocarbon fuels is a long-term prospect, especially because of the requirements for on-board hydrogen storage. Liquid hydrogen is attractive as an aircraft fuel because its energy content per unit weight is 3 times that of conventional fuels. It is the fuel of the US Space Shuttle and is being considered for use in commercial aircraft. In small vehicles, however, the cost and weight of the cryogenic container for this very low-temperature liquid fuel is likely to be prohibitive.

Production

After a decade of intensive work, direct electrolysis of liquid water remains the most viable technology for large-scale hydrogen production from nonfossil energy sources. Groups working in Belgium, Canada, the Federal Republic of Germany, France, Japan and the US have made advances which have sharply reduced capital costs and increased energy conversion efficiency to 85% and more. Canada is in the forefront of these developments.

The experimental plant which was opened at Varennes, Qué, in June 1982, is the first commercial-scale demonstration of advanced hydrogen-production technology. The technology has now been applied commercially in plants in Bécancour, Qué (HydrogenAl Inc, fall 1987), and Curitiba, Brazil (Peroxidos do Brasil Ltda, winter 1987-88). Other hydrogen production facilities include: Fast Engineering Ltd in Moscow, Russia; Sandia National Laboratories, Sandia, Calif, for the US Department of Energy; and Membrane Technology and Research Inc, Menlo Park, Calif.