The introduction of mass transit systems in major cities of Colombia has led to several socio-economic impacts, arising from the market for diesel vehicles belonging to the public transport fleet in each city. The majority of diesel engines are sold a very low cost or are stored in the junkyards of the city’s industrial sector. This article proposes the development of a methodology for the remanufacture and transformation of these engines to an exclusive operation with biogas for use as a stationary source of electricity generation in rural areas. They are not connected to the country’s electricity network. This theoretical and experimental work is based on the implementation of specialized texts in the conversion of internal combustion engines to biogas, as applied to a Caterpillar 3126E diesel engine. Following completion of the study a conversion system was made to be installed in other types of Diesel engines. The instructions for this shows how to make the construction and operational changes to the engine, such as; decreasing the compression ratio, removing the Diesel injection system, adding ignition and feeding systems for Biogas. Also the engine was tested obtaining a maximum mechanical power of 63.4 kW (85 hp) and 211 N m (155.6 lb ft) of torque at 2800 rpm. The use of these engines in this application will reduce emissions of methane in the atmosphere, will help generate employment for the industrial sector and therefore contribute to the productive development of the country’s rural areas.