The world needs more and more energy. The constant increase in population brings with it the constantly growing needs for energy and the mankind is in the ongoing search for energy sources that would be appropriate to cover energy needs. There are times when the demand for energy is temporarily reduced for some reasons such as the global financial crisis and global recession. However, such events are transient, and after them the need for energy again rises. In the long run, demand for energy is increasing all the time.
Currently, the world covers its energy needs mainly from non-renewable sources of energy, mostly fossil fuels – coal, oil and natural gas. As the name suggests, these energy sources are not renewable, they can not last forever and will disappear within a certain period of time. In addition, fossil fuels are very harmful to the environment due to releasing of large amounts of carbon dioxide (CO2) or oil spilling at sea. Now, perhaps the most pronounced negative effect of fossil fuel is global warming – probably the greatest challenge that the human race has encountered in its short history.