Bio fuels are those fuels produced from biomass and therefore they are considered as a renewable energy. They can be:
Among the bio fuels, biomass fuels belong to a subgroup that can be used for internal combustion engines (diesel engines and Otto). They are usually liquid. Bio fuels come from vegetal raw materials that have suffered biologic and physical and chemical processes.
At the moment there are two types of bio fuels:
The product that is obtained from this process is a substitute of normal diesel , even though at the moment it is used mixed with it, at 50% proportions. It is obtained from transestrifiocation of vegetable oils and animal fat with a soft alcohol, such as methanol or ethanol.
In the year 2004 13,000 tons of bio diesel were produced in
Nevertheless in other cultures as cereals, energy is stored as more complex carbohydrates as starch, that has to be hydrolysed before its fermentation into bio ethanol. It is used as additive in petrol stations. This compound substitutes traditional fossil fuels and improves its environmental effect.
In the year 2004, 194,000 tons were produced in
Biogas is obtained by the decomposition of organic matter, mainly in waste waters (therefore purifying water plants have an enormous potential), farm waste, industrial biodegradable waste (as the produced by the beer industry, sugar industry, etc), in anaerobic conditions and through direct action of micro organisms, its composition is usually about 50-70% methane (CH4) and 20-50% carbon dioxide (CO2). It can also have hydrogen and hydrogen sulphur in small amounts.
The heat value of biogas is approximately 6 Kw /m³
Bioethanol plant in Teixeiro, Curtis (Galiza)