With an area of 82,400 km2and a population of around 30 million, Chongqing is the biggest city in the world. For a number of years now the People’s Republic of China has been making serious endeavours and investment in sustainable environmental and waste management, most recently also focusing on recovering energy from green waste. However, the composition of waste in China is often unpredictable, and treating it requires a certain degree of technical flexibility. This prompted the client and local partner German Bio Energy Technology (GBE) to choose the technology leader, HZI, to deliver the planned biogas plant for the Chinese megacity. HZI’s robust Kompogas®technology takes account of the variable waste composition and assures stable production of biogas.