Towards the hydrogen economy?

The never ending debate on energy supply for a cleaner environment, recently associated with the worldwide effort to decrease global CO2 emissions, has been revived by the steep increase in oil prices and the parallel controversy about the potential of nuclear energy, initiated in the mass media on the anniversary of the nuclear disaster of Chernobyl. Thus, now seems an appropriate time for the scientific community and energy producers to exchange their knowledge in this debate far away from the magic solutions provided by mass media prophets, in an attempt to arrive at realistic guidelines that may help society to understand the important issues involved in the move towards a cleaner energy system. In this essay a description of the potential paths that may make it possible to change from the current energy sources to a cleaner energy production system is provided, the main focus being placed on how the so-called hydrogen economy might eventually be implemented. The milestones that the international agencies expect to emerge during the transition will be described, taking into account the issues of hydrogen production, distribution, storage and use. Additionally, the potential exploitation of the different hydrogen sources, both renewable and non-renewable, will be evaluated taking into account their availability and the efficiency of the processes used to transform them into hydrogen. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.