With 20 centralised plants and over 35 farmscale plants, the digestion of manure and organic waste is a well established technological practice in Denmark. These plants did not emerge without a struggle. Moreover, no new centralised plants have been established since 1998 and the development of farmscale plants has slowed down. This article reviews the experimental introduction of biogas plants in Denmark since the 1970s. We argue that three factors have been important for the current status of biogas plants in Denmark. First, the Danish government applied a bottom-up strategy and stimulated interaction and learning between various social groups. Second, a dedicated social network and a long-term stimulation enabled a continuous development of biogas plants without interruptions until the late 1990s. Third, specific Danish circumstances have been beneficial, including policies for decentralised CHP, the existence of district heating systems, the implementation of energy taxes in the late 1980s and the preference of Danish farmers to cooperate in small communities. The current setback in biogas plants is mainly caused by a shift in energy and environmental policies and limited availability of organic waste.