After berthing, vessels are typically powered by onboard diesel generators. The combustion of marine fuel oil releases emissions – including nitrogen oxides (NOx), sulfur oxides (SOx), CO₂, and particulate matter –  that cause pollution to port environments and surrounding areas. 

A shore power system enables docked vessels to seamlessly transfer electrical load from onboard generators to a shore-side power source via harbor-side connections. To meet the 60Hz power standard required by international vessels, specialized frequency-converting shore power equipment is required to transform the shore grid's 50Hz supply to 60Hz. 

The application of a shore power supply system can significantly reduce pollution emissions during vessel berthing. Approximately 90% reduction of the emission ratio in nitrogen oxides, particulate matter, and sulfur oxides. Additionally, it eliminates noise and vibration from onboard generators, improves crew working/living conditions, and reduces the unit loss and maintenance requirements.