Emissions Performance Assessment of a Retrofitted Marine Genset Combusting Biomethane in Dual-Fuel Mode

The purpose of this research article is to assess the emissions performance of a marine genset that was retrofitted to combust biomethane in a dual-fuel mode. The retrofits are part of our research efforts to provide a green cold-ironing solution for vessels at berth or in anchorage, and to advocate for a greener electrification of the port sector. An experimental campaign is presented to test the emissions performance by substituting biomethane as an energy basis. Up to 60% biomethane energy substitution is tested under low, medium, and high engine loads. The engine load is controlled via a resistive load bank, and the respective emissions were captured using portable gas analyzers. The results reveal a poor utilization of the gaseous fuel, leading to low engine efficiencies, high CO, and unburnt hydrocarbons at low and intermediate engine loads. However, marine gensets are utilized at high engine loads. At these loads, the specific fuel consumption improves. As indicated in the open literature, biomethane leads to high CO, and unburnt hydrocarbons and the respective NOx emissions drop compared to diesel-only cases.