Biogas – methane results from the fermentation of organic substances in nature, but also in technical plants. In the latter, fermentable substances are filled in containers, the so-called fermenters, and brought to a temperature of e.g. 38°C. This is the right temperature for a very efficient fermentation process through methanogenic bacteria.
Biogas consists of methane, hydrogen sulfide, hydrogen, carbon dioxide and various other gaseous materials.
Usually, the fermentation process takes place in an anaerobic area, i.e. without oxygen. Methane gas is flammable in combination with oxygen or might then even be explosive. The energy value/m³ is determined by the methane content and is always below the quality of natural gas. However, the quality can be upgraded through special treatment.
The technical production of biogas has developed rapidly over the last years. While waste products were used as fermentation substrates initially, one uses mainly renewable raw materials like maize silage, green waste or turnips in modern large-scale plants today.
This kind of energy production is desired by politicians and supported by a government-fixed pricing system ("EEG = Energie-Einspeise Gesetz"). The aim is a better energy supply for own needs in order to reduce the dependence on foreign suppliers. Agricultural businesses are optimal locations for such biogas plants as they produce the required renewable raw materials and the residual nutrient solutions of fermentation processes can be disposed of on fields and plants.
Thus, there is a circulation system which - in combination with sun power (photosynthesis) - permanently generates new and large amounts of energy. This system can be described with the term "sustainability".
There is a variety of applications for the use of methane gas. Currently, this gas is often converted into power and heat by means of so-called combined heat and power units (CHP). The resulting power is fed into the network. However, many plants produce a surplus of heat which cannot be used in a meaningful way. Optimal cost effectiveness can only be reached, if the produced energy is completely exploited.
First plants feed the methane gas directly into the gas distribution system after having it cleaned and brought to the quality of natural gas. Thus, the whole energy is brought to the end user. Systems for the subsequent generation of electricity from waste heat are relatively new. Such systems convert heat into pressure, which is then led to a turbine. This turbine converts about 30 % of the available residual heat into power with the help of a generator. These systems offer promising starting points for further developments.
Apart from the smaller plants which are located on farms and produce normally not more than 1000 kW of electricity, there are also commercial plants, operated by companies and located in industrial areas, which produce meanwhile electricity of up to 10 Megawatt.
In contrast to wind power, photovoltaic systems and other energy generation systems whose basic materials must be consumed as far as possible at the time when they occur, the production of biogas offers particular advantages with regard to the storage of the required substances, the control of the output and the gas storage. This development has led to considerable changes in the agricultural business, since parts of the feed and/or food production are now being used for the production of energy and are thus missing on the total market.
Since the construction of the first professional biogas plants in the nineties, TEWE-Elektronic has been dealing with this business and has gained a lot of experience in this field. We have equipped and activated more than 200 plants of different manufacturers with our control systems. Today, we can offer and supply complete biogas plants and we are active in all over Europe. Our photo gallery shows some plants which were partly or completely constructed by us.