The G20CM34 is a spark ignited engine operating according to the lean burn combustion system. The use of a pre-chamber operated by means of a spark plug enables a combustion at high efficiency and low emissions. The cylinder-pressure based engine management of the G20CM34 enables engine operation at the efficiency optimum. The single-stage turbocharged, charge air cooled 20 cylinder engine reaches an electrical efficiency of up to 48 % and an overall efficiency of up to 93 %. Two charge air coolers allow a maximum utilization of the available displacement. A two-circuit cooling water system ensures flexibility. With a high temperature (HT) and a low temperature (LT) stage each, individual configurations for high altitudes of installation, high intake air temperatures, and natural gases with varying methane numbers are available. Depending on the requirements, these configurations can be optimized for purely electric power generation and combined heat and power. Stable engine operation at varying natural gas qualities is ensured by means of cylinder-specific knocking detection and continuous NOx control. An optimum material design (as e.g. the flow-optimized gas supply in the cylinder head) ensures a long service life of the components. Low fuel and lubricating oil consumption as well as low maintenance effort cater for high availability and cost efficiency of the engine.