Real-world carbon dioxide and atmospheric pollutant emission characteristics of inland waterway ships

A ship emission measurement system was established using portable emissions measuring system (PEMS), global positioning system (GPS), shaft power meters, temperature and humidity sensors, and other instruments. The real-world characteristics of carbon dioxide (CO₂) and air pollutant emission from inland ships were investigated, enabling high-precision measurement of energy consumption and emission data during ship operation. Based on the constructed system, onboard measurement tests were conducted on three major types of inland ships. The energy consumption and emission data of the ships during operation were collected. The steady-state tests of the main ship engine were performed at load conditions of 25%, 50%, and 75% to measure stable energy consumption and emissions. Based on the collected data, the emission factors of gases were analyzed with the carbon balance method. By combining the main engine power data, the characteristics of actual CO₂ and air pollutant emissions from the ships were analyzed. Analysis results show that the main engine load of ships during operation is mostly below 50%. This prolonged low-load operation is the primary cause of increased CO₂ and air pollutant emissions. The power-based emission factors for carbon oxide (CO) and CO₂ are found to be higher during docking and departure than during cruising or maneuvering. When the main engine is in a steady state, the emission of CO₂ and air pollutants is significantly related to engine load and fuel type and decreases with the higher engine load. At relatively high and stable engine load levels, nitrogen oxide (NO_x) emissions are reduced.