What is Biogas?
A combustible gas (composed primarily of methane) produced when sewage or manure is fermented in the absence of oxygen. The solid material that remains in the digester after fermentation can be used as an organic fertilizer.
Biogas - a gas mixture of methane, carbon dioxide and small quantities of hydrogen and hydrogen sulphide - is created under air exclusion through the fermentation of organic substances with microorganism assistance. Biogas is a gas mixture, consisting of approximately 40 to 75 % methane (CH4), 25 to 60 % carbon dioxide (CO2), and approx. 2 % of other gases (hydrogen, hydrogen sulphide and carbon monoxide).
Biogas out of waste and sugar
The German biogas industry
Power generation from gaseous biomass has greatly expanded in Germany in recent years to become an independent sector within the fast-growing bioenergy industry.
Applications and technologies
Medium to large-scale biogas plant
When organic material is fermented under anaerobic conditions, a gas mixture containing methane is produced. This biogas can be used for energy generation. Today, on many farms in Germany, biogas is being produced from agricultural waste products, commercial waste or specially grown energy crops. Here, knowledge of process engineering and process control is needed. Because the productivity of biogas plants depends crucially on microbiological processes during fermentation, knowledge of biotechnology for plant optimisation is required in addition to technical expertise. German companies are carrying out pioneering work in the development and design of such systems.
Medium to large-scale biogas plant
When the conditions are right, biogas is used to generate electricity and heat in decentralised combined heat and power plants (CHPs). After being specially treated, biogas can also be fed into the existing natural gas network. Transport via the natural gas network means that biogas can also be used in larger power plants for electricity and heat production. Biogas can then be used in the transport sector in the same way as natural gas.
German companies are leaders in the field of biogas technology. Their range of products and services spans the entire value-added chain: from designing and building biogas systems to operating and maintaining them. Many years of experience in operation management, process biology and related laboratory services guarantee successful plant operation. Technically mature products are additionally available for storage and tank systems, for specialised combined heat and power plants, and for biogas analysis technology.
Market trend
Source: German Biogas Association (FvB)
2006 has been the most successful year for the German biogas industry so far: A total of around 650 systems were newly installed, representing an increase in the number of plants to 3,500 in 2006, with the volume of installed electrical capacity totalling around 1,100 megawatts. These systems produced approximately 5.4 billion kilowatt hours of electricity from biogas in 2006. Another sharp increase in production is anticipated in 2007.
The German biogas industry has increased its exports (see graph above). The German Biogas Association expects to attain a share of nearly 30 per cent of exports by 2020.
Source: German Biogas Association (FvB)
The development in the plant size shows a clear trend towards larger, high-capacity systems. Whereas in the past farmers often built and operated the systems themselves, an increasing involvement on the part of energy suppliers and professional energy service providers can be observed in the course of this development. Thus larger systems are often created with the cooperation of parties from both agriculture and the energy industry. In both cases, positive structural developments in agricultural regions are linked with the creation of new jobs.
An important stage in the development of feeding treated biogas into the natural gas network was completed in 2006: two pilot projects were successfully put into operation. Further systems for biogas grid feeding are currently in the planning stage in Germany.
Regulatory framework
Biogas plant for feed-in to the gas network
In Germany, electricity generation using biogas is subsidised under the Renewable Energy Sources Act (EEG). Depending on the system’s output, the biogas-produced electricity fed into the grid is purchased at a tariff that will remain fixed for 20 years. Additionally, bonuses are paid for using renewable raw materials, for innovative energy technologies and for extracting the heat produced during electricity generation.
The regulatory framework created by the EEG has proved to be a particularly effective driving force for the growth of this young industry.
