Bioenergy, solar energy and geothermal energy are among the most important types of renewable energy sources, which contribute to a more efficient energy use, climate change mitigation, and environmental protection. Upgrading biogas to biomethane production has become one of the most interesting targets in recent years, as a proper alternative source for fossil fuels. Despite this method is highly efficient process, it requires a high thermal energy demand for anaerobic digestion in addition to more required electricity required for upgrading biogas into the biomethane. This study investigates two methods of utilizing biogas: converting the total biogas into the biomethane and converting a portion of the biogas into the biomethane and the remainder is used in a combined heat and power (CHP) generation.