In modern society energy has become indispensable like food, water and air. However, most of the energy we use nowadays comes from fossil fuels, a non-renewable energy source. Furthermore, our dependence on fossil fuels as energy sources has caused serious environmental problems, i.e. air pollution and greenhouse gas emissions, and natural resource depletion. It is emphasized that the global environmental damage caused thermodynamically is more alarming to life on earth than the risk of exhausting the finite amount of fossil fuels being consumed at the present rate. The need for alternatives...