|| Treatment of biogas is being increasingly regarded as an option for using renewable energy in the future. Biogas from fermentation or thermochemical transformation is the only regenerative alternative towards obtaining the fossil energy source natural gas. In treating biogas to the quality of natural gas, it is basically possible to cover all the natural gas applications with biogas. Comparable to electricity, even gas can in principle, then enter the market as a „green“ source of energy. At the same time however, the purpose of this development is questioned. Is the treatment of biogas energetically and ecologically worthwhile? For what applications does it make the most sense to substitue fossil energy sources with treated biogas? Therefore, apart from technical problems, questions concerning ecology and energy efficiency should also be discussed in this article.