Hydrogen Energy and Environment

Energy consumption per capita is a kind of indication of the development for a society. Energy sources, today, are mainly fossil fuels (coal, oil and natural gas) which can cause severe environmental problems such as acid rains, global warming and climate changes. In addition to severe environmental problems, the sources of fossil fuels are finite. Because of increasing need of energy, researchers are forced to search for renewable energy sources such as hydro, biomass, wind, solar, geothermal, wave, tide and so on. Hydrogen (H2) seems to be promising for a clean energy source. In fact, it is a clean energy carrier with a role to save environment. H2 is universally accepted as a clean energy carrier because of its high energy density. It does also reduce the emission of greenhouse gases by using it as fuel in fuel cells or in combustion engines directly. For usage of H2 as fuel, it is necessary either to compress it or to liquefy it. Both processes are difficult and costly. Metallic and nonmetallic hydrides have received considerable research interest in recent years. NaBH4, is the one of the most prospective H2 storage materials as it stores 10.8 w % hydrogen. H2 is generated by the following hydrolysis reaction of NaBH4 in the presence of a suitable catalyst: NaBH4 + 2H2O › NaBO2 + 4H2 In this reaction, half of the hydrogen produced comes from the water which is a great advantage and make it effective on hydrogen generation for fuel cells such as portable Proton Exchange Membrane (PEM) fuel cells applications. Another great advantage of fuel cells, one can bypass the 2nd law of thermodynamics where the efficiency is limited by Carnot Cycle. Therefore, the efficiency is much higher as compared to conventional mode, which is Chemical Energy › Heat energy › Mechanical Energy› Electrical Energy There are more intermediate steps, hence lower efficiencies.By using fuel cell, however, it is possible to convert the chemical energy directly into electrical energy Chemical Energy › Electrical Energy With Fuel cells, Carnot Cycle Limitations are by-passed. Hence, the future of fuel cells is very bright and H2-economy will probably dominate in very near future. In this study, the environmentally friendly future of fuel cells will be discussed in details.