Spatial-economic optimisation of biomethane injection into natural gas grid: The case at southern Malaysia

Energy is widely used in industry for heating and cooling, with natural gas (NG) being the largest primary energy source in Malaysia, closely followed by coal. Renewable energy, such as biogas upgrading to biomethane, could cut the use of fossil fuels by supplementing NG usage due to their similar physicochemical and thermochemical characteristics. Biogas production plants in Malaysia are more commonly seen in waste-to-energy scenarios, with the technology anaerobic digestion, and their deployment is supported via feed-in tariffs (FiT) for power generation. Other potential applications such as the conversion of biogas into biomethane, injection into the natural gas grid or transportation through a virtual pipeline may still need further technical development. This paper presents spatial techno economic optimisation modelling using BeWhere to determine decentralised biomethane production plants using feedstock from multiple sources of biogas, including palm oil mill effluent (POME), food waste, cattle manure and chicken manure. This model considered potential configurations and sizes of the biomethane plants, the transportation of biomethane using a virtual pipeline (at 250 psig) and demand in one of the states in Malaysia, namely Johor. It was found that two to four biomethane plants with capacities ranging between 125 and 700 m³/h were located in densely populated areas or heavier industrial consumers when the carbon tax was implemented at 167.71 EUR/tCO₂ (800 MYR/tCO2). Sensitivity analysis suggested that biomethane production increases with the increasing country renewable energy share target to beyond 2080 MW. It is recommended that specific policy regulations and Feed-in Tariff (FiT) mechanisms are used to expand the biomethane market share in the country.