Biogas into the natural gas grid: Challenges for the design, construction and operation of biogas feeding plants
In Germany the role of renewable energies is subject to statutory regulation in many areas. In accordance with the energy concept of the German federal government regenerative energies will be responsible for generating at least 80 percent of the country’s electricity by the year 2050. The aim is to cut energy consumption in half by the year 2008 and reduce emissions of environmentally harmful gases by up to 95 percent compared with the year 1990. In addition to wind and solar installations, gases produced from regenerative sources (e.g. biogas, hydrogen from power-to-gas) are to make a substantial contribution toward meeting these targets. Thus, for example, up to ten billion cubic meters of bio-natural gas are to be supplied to the existing gas grid by the year 2030. Grid operators such as ONTRAS are obliged by law to connect biogas installations to the grid and give preference to the transport of bio-natural gas. To this end the raw biogas is processed to natural gas quality and then supplied to the gas grid by means of a corresponding feed-in facility. Allocation of the costs for the treatment and supply of the biogas as well as construction and operation of the corresponding plants are regulated by law. Thus far, however, there are no incentives for consumers to purchase bio-natural gas. Moreover, changing framework conditions and diminishing acceptance of biogas facilities on the part of the general population make new investments more difficult. This development has put the aim of achieving climate policy targets with the aid of biogas at risk.