Environmental Performance of Onshore Power Supply in Ports: Emission Reduction Potential, Energy-System Conditions, and Policy Challenges

Abstract

Onshore Power Supply (OPS), or cold ironing, is one of the crucial technological solutions to reduce greenhouse gas (GHG) emissions and air pollution from ships’ auxiliary engines at berth and support the global greenhouse gas (GHG) reduction targets. However, the OPS expansion remains complex due to energy resource management and environmental engineering challenges, including utility grid capacity limits, electrical frequency conversion, and the availability of clean energy sources. This study reviews the environmental performance of OPS and examines the technological, energy-system, economic, and institutional conditions that determine whether its potential emission reductions can be realized in practice. As a result, three remaining findings were identified: (i) the incompatibility between technical standards and electrical connection of ships and shore; (ii) ambiguous grid connection responsibilities and peak-demand electricity tariff dynamics, creating the investment dilemma; and (iii) policy fragmentation across maritime, energy, and environmental domains. The comparative case studies of the EU, California, Hong Kong, and Mainland China emphasize that the deployment of OPS requires synchronized energy governance, standardized electrical infrastructure, and economic and political alignment to maximize its performance.