The Hydrogen Economy

Concern over the adverse effects of continuing fossil fuel consumption, such as global climate change and urban pollution, has led to consideration of alternative, 'clean', energy sources. The term hydrogen economy describes an overall national energy infrastructure based on hydrogen produced from non-fossil primary energy sources. Within this concept, hydrogen is regarded as a suitable storage and transmission vector for energy from renewable or nuclear power systems, allowing the generator or utility increased flexibility in responding to fluctuations in wind or solar input or consumer demand, on a diurnal or seasonal basis. Hydrogen can be stored and transported in pressure vessels or transmitted by pipeline to the point of end-use. Hydrogen has more energy per unit mass than any other fuel and it avoids or substantially reduces carbon dioxide and other emissions at the point of use (which makes it attractive for transport applications). It can easily be substituted for traditional fuels, whether for stationary or transport applications, resulting in improved efficiency and negligible pollution. In the transportation sector, many automotive manufacturers consider hydrogen to be the leading contender for a new generation of highly efficient 'zero-emission' vehicles.

The principal drivers behind the current interest in the hydrogen economy are therefore:

Hydrogen's main drawbacks are its low density and consequent low volumetric heat content (approximately 25% that of natural gas) and the complexity and energy intensity of the overall energy chain.

The implementation of a small-scale integrated hydrogen system or a national hydrogen infrastructure requires a multi-disciplinary approach. For example, chemical engineers and electrochemists are required to understand the detailed processes taking place in electrolysers and fuel cells, solid state physicists and material scientists are required to work on the storage of hydrogen in metal hydrides and activated carbon structures, experts in cryogenics are needed to refine liquefaction processes, and control engineers are needed to manage the interaction of all the system components. The ultimate move to a hydrogen-based energy economy will require a concerted effort to replace and upgrade the existing energy infrastructure, thus drawing in energy economists and power systems and control engineers.

Research and development activity towards implementing some or all of the aspects of a hydrogen economy is concentrated in five major areas:

 

 
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