First of all I want to point out what renewable energy is. This "clean energy " is supplied by unlimited resources. Renewable energy is therefore gained out of hydropower, wind energy, solar energy, geothermal and renewable resources, like corn for a biogas power plant. All other energy sources are known as fossil fuels. A fossil fuel is, for example, oil or coal. To make these it took millions of years and a lot of pressure of the earth layers. The first difference we have already mentioned between these two different kinds of energy: the duration to rebuild those. While renewable energy is always present in sun light, flowing water, or is produced in a low time margin compared to a human life, fossil fuels take many millions of years to rebuild. Raps for example, grows in less than one year and is used to make fuel, whereas oil takes 100-400 million years. .
Also the reservoir of fossil fuels in limited. In the opinion of experts the duration until the resources are depleted is 40-100 years. Furthermore the low stock of oil is the reason for the exploding prices for benzoin and diesel in Germany. A research shows that during 10 years the price for one Liter benzoin was tripled. This is another a benefit of the renewable resources. They are unlimited and through their use the fossil fuels are saved and can be utilized in the chemical industry. This industry is mainly based on oil, because plastic and other synthetic substances are mainly synthesized out of this resource. Furthermore we have already said that renewable energy is also called "clean energy ". The reason is simple. Fossil fuels are burned in power plants. This releases a high amount of carbon- dioxide. The carbon-dioxide gas in the atmosphere reflects the heat, which is submitted by the earth. Through this the ozone layer, which protects the earth surface of radioactive sun radiation, is damaged through this. This phenomenon is called "the greenhouse effect ".