Onshore Power Supply (OPS) Introduction
During the ship’s port operations and at berth, auxiliary engines are run in order to generate electricity for supply to ship-board systems as well as to the cargo loading or loading/unloading machinery, where applicable. Today, this power is generally provided by auxiliary engines that emit carbon dioxide (CO2) and air pollutants, affecting local air quality and ultimately the health of both port workers and nearby residents.
As an alternative to on-board power generation, vessels can be hooked up to an onshore power supply, i.e. connected to the local electricity grid. In this way ships’ operations can proceed uninterrupted, while eliminating negative side-effects. The amount of power generated, and fuel consumed is dependent on type of ships and could be anything from a few hundred kW to several MW of electric power. The operation of auxiliary engines is a major source of SOx, NOx and Particulate Matters (PM) emissions to ports. The amount of emissions is generally proportional to the amount of fuel used. The longer the ship stays at berth or at anchor, the higher the ship fuel consumption will be and thereby the more the exhaust pollutants emitted to the port. Concern over air quality in ports has led to growing pressure on port operators to reduce exhaust emissions; in particular pollutants of SOx, NOx and PM. The supply of power from onshore (port) to ship is one system that has been advocated for this purpose. Use of this system allows ships to turn off their auxiliary engines when in port and plug into a shore-side electricity supply. As a result, not only air emissions to port are reduced but also it helps positively with other aspects of the ship and port operations. It is claimed that this system, in addition to the environmental and social benefits, could provide economical savings to all stakeholders. However, this last point has yet to be validated (MariEMS 2017).