Biofuels are liquid or gaseous fuels for combustion engines that are produced from biomass. The source materials can be oil plants, grain, sugar cane, wood or organic waste, for example. Biofuels are divided into first- and second-generation fuels, with algae-based fuels sometimes already being referred to as third-generation fuels.
First generation fuels - vegetable oils
In the case of first-generation fuels, only part of the plant is used. This primarily includes vegetable oils, which can be used in combustion engines either in their natural state or refined. In Germany, rapeseed oil is mostly used for this purpose. This biofuel is particularly popular in agriculture and rural regions. In the past decade, the "100 Tractors Program" demonstration project, in which tractors were converted to run on pure vegetable oil, caused quite a stir.
Biodiesel (FAME)
Biodiesel, a fatty acid methyl ester, FAME for short, is more widely used. It is standardized in accordance with DIN EN 14214 and is produced from vegetable oils - in Germany mostly rapeseed. Today, it is almost exclusively marketed by blending it with mineral diesel fuel, since the German government has stipulated a minimum proportion of biofuels in the Biofuels Quota Act. Up to 7% by volume can be blended with diesel fuel in accordance with DIN EN 590, whereby the fuel is then designated B7. B7 has been the standard fuel for diesel-powered vehicles in Germany since 2009.
Hydrogenated vegetable oil (HVO)
In recent years, hydrogenated vegetable oil (HVO = hydrotreated vegetable oil) has also gained in importance. The starting materials for HVO are any oils and fats. Compared to FAME, HVO biofuel is a hydrocarbon that is almost identical to the chemical composition of diesel fuel. The advantages are obvious. It can be added to diesel fuel in any mixing ratio as long as the diesel fuel standard DIN EN 590 is met. In terms of ageing resistance, HVO is far superior to biodiesel.
Aviation fuel
In addition to its use as a blending component in diesel fuel, initial experience has already been gained as an aviation fuel. As with biodiesel, its use as a pure fuel makes no sense from a tax perspective in Germany.
Bioethanol
Bioethanol , which is obtained by alcoholic fermentation and subsequent distillation from plants containing starch (primarily grain, sugar beet, sugar cane and maize), is also still a first-generation fuel. The quality of this biofuel is regulated in DIN EN 15376. Petrol containing a corresponding percentage of ethanol is marketed under the names E5 and E10; most of today's vehicles can fill up with this fuel without any problems. However, fuels with a higher ethanol content (E85 or even E100) are also marketed, although this usually requires modifications to the vehicle.
Second-generation fuels - biomethane (CNG)
Biomethane is a second-generation fuel that uses whole plants or organic residual and waste materials. Methane is produced in the fermenter of a biogas plant through a biotic reaction in the absence of air. As the raw biogas only consists of around 60% methane by volume, it must be processed by separating out other gases (primarily carbon dioxide, but also hydrogen sulphide). As largely pure methane, it is then on a par with natural gas from a chemical point of view and can therefore be refueled by any natural gas vehicle (see also Bio-CNG ).
BtL fuels (biomass-to-liquid)
The most complex processes are those for the production of so-called BtL fuels (biomass-to-liquid). Wood, for example, can also be used as a raw material. In the first step, a synthesis gas is produced by gasification, which is then liquefied, e.g. by Fischer-Tropsch synthesis.
Fuels from algae
From a purely technical point of view, these biofuels pose no problems. There have already been successful trials in aviation, where the use of renewable energies is otherwise difficult. Nevertheless, large-scale use is not foreseeable for the time being for cost reasons.
Fuels such as biofuels are traded via the MB Energy Group. enport is active in tank storage logistics.
