Biofuels are fuels that are produced by the refinement of living or recently living material (biomass). The primary source of this is commonly plants. When burned, the fuels release carbon dioxide into the atmosphere and the energy that is produced by the burning can be harnessed (e.g. to power a turbine). Due to the fact that the material takes in carbon dioxide whilst growing, it is said that there is no net increase in carbon dioxide concentration in the atmosphere when biofuels are burnt. This makes biofuels an interesting prospect when looking at how to dimish the amount of carbon dioxide we release into our atmosphere.