Characteristics of real-world ship energy consumption and emissions based on onboard testing

The Yangtze River ships are generally overpowered and less energy efficient. In this study, a Yangtze ship was selected as the test ship, and its characteristics were investigated through energy consumption and emission testing under multiple operating conditions. The results show that the ship operates at 25-50 % engine load for 72.2 % of the time, and at this partial load, 9.72 % more CO₂ and 9.81 % more NO_X can be emitted than at the rated power. The concentrations of exhaust vary under different operating conditions. The emission factor of CO was the highest under departure conditions; CO₂ and SO₂ were the highest under anchoring conditions; and NOx was the highest under cruising conditions. The accuracy of the emission factors obtained by the direct calculation method was improved by 30 % compared to the concentration estimation method. This study can help understand the real level of energy consumption and emissions from in-service ships.