Biofuels are fuels produced from plant raw materials or derived from living organisms (hence their prefix "bio"). They are thus in contrast to the "fossil" fuels that result from a degradation process taking several thousand years. The development and use of these new fuels have many advantages both in financial and environmental terms.
Benefits and environmental impacts of biofuels
In theory, biofuels offer the advantage of not increasing the carbon dioxide (CO2) emissions. In fact, the CO2 emitted during their use is captured throughout the growth of the plant organisms from which these fuels are derived. Therefore biofuels do not create new CO2 molecules as do the fossil fuels.
However, the cultivation and conversion of these plant raw materials also cause impact on the environment:
• CO2 emissions for cultivation, conversion, transportation,
• CO2 emissions and loss of biodiversity through the appropriation of new areas for cultivation,
• emissions of pollutants through these operations, use of fertilizers,
• competition with food crops.
Just as there are different fossil fuels, there are several kinds of biofuels. In order to use them in pure form, engines are generally required that are specifically suitable or designed for them. This is why, at present, they are used in engines in which they can be mixed with their fossil counterparts.
The four most known and currently produced biofuels in Europe are:
1. Bio-ethanol is produced from biomass and/or the biodegradable fraction of waste used as biofuel. The plants most used in Belgium at present are sugar beet and cereals (wheat, barley, etc.).
2. Bio-ETBE "(ethyl tertiary butyl ether)" is an oxygenated compound derived from the reaction in almost equal quantities of bio-ethanol and isobutene. This product is being preferred by the oil companies. ETBE has the advantage that it can perfectly blend with petrol, can be incorporated with it at any time and can be transported along with it without special precautions. It is commonly used to improve the octane number of petrol.
3. Pure vegetable oil is produced from oilseed plants (coleseed, etc.) through pressing, extraction or other crushing processes (Reduction of a solid substance into particles or paste, by crushing it).
4. Biodiesel (= FAME fatty acid methyl ester) is composed of methyl esters of vegetable oil. These compounds are obtained by a reaction between a pure vegetable oil (such as coleseed, sunflower or soybean) and methanol. By combining 90 units of oil to 10 units of methanol (transesterification reaction), we get 90 units of methyl esters of vegetable oil and 10 units of glycerine (by-products used in the chemical and food industry).
Biofuels: Solution or Problem?
Biofuels are presented both as a solution and an environmental problem. To confirm the theoretical interest of biofuels, their production must meet certain conditions.
• The production of plant raw materials must limit adverse effects on the environment.
For this purpose, Europe, in its legislation (Directive 2009/28/EC) has defined sustainability criteria:
in comparison with their fossil counterparts, biofuels should induce a reduction in CO2 higher than a specified percentage;
areas from where the plant raw materials are sourced, must comply with specific rules (in environmental and social terms).
Care must also be taken to avoid competition with crops meant for food. This competition raises an ethical question on the one hand, linked with the use of agricultural production for energy instead of food. On the other hand, this competition can play a part in the increase of prices of agricultural products for food with the increase in demand (especially in emerging countries) and unfavourable climatic factors.
• The conversion into biofuel must be as efficient as possible.
There are 2 generations of biofuels. They differ in their yield:
the first generation uses only some parts of the transformed plants (grains, roots, etc.) as raw material and therefore generates waste ;
the second generation uses all parts of the plants. It may therefore also recover plant waste.
Furthermore, depending on the plants that are cultivated, the production of raw material per hectare (= yield) can vary in quantity.
On the other hand, biofuels can help in reducing our energy dependence. Producers of plant raw materials are not necessarily the same as the producers of petroleum. These also provide new opportunities for the agricultural world and help in less soil depletion through crop diversification.
In Belgium, biofuel producers and importers have to register each biofuel batch placed on the market in a database, before selling them to their customers.