The technology group Wärtsilä introduces an upgraded version of its popular and successful Wärtsilä 20DF dual-fuel engine. The new version will deliver increased power output, have a reduced environmental impact, and will feature a lower fuel consumption. It will also further increase the engine’s fuel flexibility by allowing a much wider gas quality span, down to methane number (MN) 65, while still delivering full output.The engine’s power per cylinder is increased from 185 to 195 kW, while the methane slip is lowered by as much as 40 percent, thereby drastically reducing the CO2 emissions. The existing Wärtsilä 20DF control system is replaced by the latest Wärtsilä UNIC all-inclusive automation system. For gen-set applications, skip-firing technology combining torque control with cylinder deactivation to optimise fuel consumption at low engine load, is introduced. Energy consumption is reduced by three percent.The new Wärtsilä 20DF engine is better suited for variable speed applications with mechanical propulsion.