Green Energy and Technology Series

Hydrogen Technology

Published 21 July 2008

Aline Leon In the last years, public attention was increasingly shifted by the media and world governmentsto the conceptsof saving energy,reducingpollution,protectingthe - vironment, and developing long-term energy supply solutions. In parallel, research funding relating to alternative fuels and energy carriers is increasing on both - tional and international levels. Why has future energy supply become such a matter of concern? The reasons are the problems created by the world's current energy supply s- tem which is mainly based on fossil fuels. In fact, the energystored in hydrocarb- based solid, liquid, and gaseous fuels was, is, and will be widely consumed for internal combustion engine-based transportation, for electricity and heat generation in residential and industrial sectors, and for the production of fertilizers in agric- ture, as it is convenient, abundant, and cheap. However, such a widespread use of fossil fuels by a constantly growing world population (from 2. 3 billion in 1939 to 6. 5 billion in 2006) gives rise to the two problems of oil supply and environmental degradation. The problemrelated to oil supply is caused by the fact that fossil fuels are not - newable primary energy sources: This means that since the rst barrel of petroleum has been pumped out from the ground, we have been exhausting a heritage given by nature.