One of the ways to produce biogas, in controlled conditions, is to build a power plant. The main technological parts of a biogas power plants are the part for the production of biogas and the part for electrical and thermal energy production. Biogas production is conducted in large airtight tanks called digesters. Depending of the chosen technology, the gas creation process usually last 30 up to 60 days.
Of course, the longer the period, the more biogas is produced, but the price of such a power plant increase due to the construction of larger or additional digesters. Biogas produced in this way can be used for running the gas engine, which runs the generator, producing electrical power, and thermal power. The gas engine and the generator are ususaly made as a single device, because aside from the electrical, it also produces thermal energy, and it is called cogenerator.