An environmental and economic investigation of shipping network configuration considering the maritime emission trading scheme

Decarbonization is currently an urgent issue for the international shipping industry. The maritime Emission Trading Scheme (METS) is an effective measure, while the utilization of the Arctic Northeast Passage (NEP) and carriers' profit-driven reactions may affect its effectiveness. Thus, this paper proposed an optimization model to investigate the carrier's economic viability and the CO2 emission under METS for the SCR/NEP-combined liner shipping service. Various METS scenarios are set based on 1) geographical scope (GS), 2) free emission quota percentage (FEQP), and 3) carbon price (CP). Results show that METS would guarantee a short-term CO2 emission reduction within the GS, but the volume of overall CO2 emission in some scenarios would be even larger. In individual cases, METS positively affects the carrier's economic viability. METS disincentivizes carriers to use the NEP, especially when it is implemented in the Arctic area or with high pricing. For carriers, the main countermeasure to cope with METS is slow steaming in the GS. Some valuable insights for policymakers designing METS: it is not the case that the higher the value of GS/FEQP/CP, the better the overall CO2 emission reduction effect. A moderate GS and CP may be appropriate for balancing carriers' economic benefits and emission reduction efficiency, in whole or in part. FEQP can be set relatively low at the start of METS and raised gradually to motivate the carriers in emission control.