Bioenergy – energy in many forms

Biogas is obtained by fermenting biomass in airtight tanks, so-called digesters, anaerobically using microorganisms (bacteria). The resulting raw biogas is collected in the “dome” of the digester. It is then either converted into green electricity and heat on-site in a CHP (combined heat and power plant) or upgraded to produce biomethane.

Biomethane is a renewable alternative to fossil fuel natural gas. Biogas is firstly needed in order to be able to produce biomethane. In a biogas upgrading plant, the biogas is then “purified” to remove the carbon dioxide, water vapor and hydrogen sulfide. Once upgraded, it has the quality of natural gas and can be fed into the existing natural gas grid.

Biomethane can be transported to consumers via the existing natural gas grid. Its potential uses range from power generation and heat generation to use as a fuel for natural gas vehicles. Compared to other renewable energy sources, biomethane has the advantage that it is well-suited to storage and can therefore generate electricity and heat flexibly in line with demand.

The biomass fermentation process produces biogas on the one hand, but also digestate. However, this should by no means to be described as “waste” because it can be reused by farmers. It is firstly stored in the digestate storage facility before being made available again to the agricultural sector as a virtually odorless fertilizer. This high-quality organic fertilizer can supplement and, in most cases, completely replace the mineral fertilizer normally needed, which is obtained from ores, salts, gas and oil.

EnBW is already working with scientists from the University of Hohenheim and the Karlsruhe Institute of Technology (KIT) to conduct research into alternatives forms of biomass. In the course of this collaboration, various cultivation scenarios with a plant mix that can be economically converted into biogas have already been identified for Baden-Württemberg. Playing a key role in these scenarios is strip cropping as part of a special crop rotation system in conjunction with permanent crops. The potential is currently being determined on the basis of a field trial in the Biberach region with the involvement of farmers. EnBW is continuing to research new ways of making even greater use of waste material for biogas production.

Biomethane represents part of our commitment to a sustainable, climate-friendly energy supply. There is certainly still a great deal of development potential, but it will also reach its environmental and economic limits at some point. That is why we are focusing on expanding capacity for various renewable energy sources by investing in wind and hydropower, for example.

Our biomethane is produced in two ways. On the one hand, production is based on the fermentation of biowaste. In this sense, all residual materials classified as organic waste in the Biowaste Ordinance are considered biowaste. These include kitchen scraps, overstocked food and many other kinds of waste. Yet it is also obtained from energy crops such as corn in the form of wholecrop silage (the entire corn plant chopped), cereals in the same form, green waste from meadows and fields, and manure.

There are no costs for you when switching to biomethane. You only pay the costs set out in your usual tariff, which are made up of the price of gas, among other things. Immediately after being processed, the biomethane is fed into the existing natural gas grid and can be used to generate heat in existing appliances such as a gas condensing boiler. No expensive conversions or special heating systems are required.

For EnBW customers, there is our Biomethane 10 tariff, where 10% biomethane is added to the natural gas. To change your gas supplier and check availability for where you live, or to find out more information, visit our biomethane tariff pages.