Sustainability

Energy

Biomass

Environmental impact

Through the chlorophyllous photosynthesis, a total amount of 2 x 10¹¹ tons of carbon are fixed each year, with an energy content of 70 billion tons of oil, that is around 10 times as much as the current global energy need.
It should be remembered that the exploitation of biomass implies an environmental impact too. In some cases the use of wood as fuel, if it does not comply with the principle of sustainability (i.e. making sure of restoring the heritage of felled trees) can lead to a progressive deforestation, a process currently affecting some areas lacking alternative energy resources.
At present, great part of the energy supplied by biomass is derived from firewood. Some developing countries, especially in Africa, cover over 70% of their energy needs by means of firewood, a resource that, owing to excessive exploitation, in certain areas cannot be considered renewable.
Moreover, the intensive cultivation of some plants aimed at producing energy (so-called energy cultures) not only needs large surfaces of land to obtain meaningful fuel amounts (land is taken away from food-producing agricultural activities), but may also involve the use of fertilisers and other soil and water polluting substances.