The diagram illustrates how ethanol, a type of biofuel, is produced from plant material and how its use forms part of a continuous cycle.
Overall, ethanol production is a cyclical process that combines natural and industrial stages. Plants first grow by using sunlight and absorbing carbon dioxide from the atmosphere. They are then harvested and converted into ethanol, which is subsequently used as a fuel. When the fuel is burned, carbon dioxide is released and later absorbed by new plants, allowing the cycle to continue.
Initially, plants grow naturally with the help of sunlight and carbon dioxide. Once they have reached maturity, they are harvested and sent for processing. During this stage, the plant material is converted into cellulose, which is then broken down to produce sugars. The sugars are subsequently fermented, resulting in the production of ethanol.
In the final part of the process, the ethanol is used as a fuel, for example in vehicles. Burning this biofuel releases carbon dioxide into the air. Rather than remaining permanently in the atmosphere, this gas is absorbed by plants during their growth. As a result, the same natural materials can be used again to produce more ethanol, thereby completing the cycle.