The global movement towards achieving a low-carbon or decarbonized society is accelerating. Being able to supply both heat and power, gas cogeneration systems are a distributed energy system with energy conservation features. Gas engines are part of the equipment used for electricity generation in gas cogeneration systems. Mitsubishi Heavy Industries Engine & Turbocharger Co., Ltd. (MHIET) offers a lineup of gas engines covering the range of 315 kW to 5,750 kW per unit, and can therefore provide products for use as small-scale distributed power sources, cogeneration systems for facilities, factories and such, or power generation for utility supplies using multiple units. This report presents MHIET's gas engine product lineup and the characteristics, CO2 reduction effects, and the prospect of technological advancement.