Shore Power

Shore power, also referred to as Onshore Power Supply (OPS), is a key approach to reducing emissions from vessels hotelling at berth during port stays. While at berth, vessels typically rely on auxiliary engines powered by fossil fuels to meet onboard electricity demands, including lighting, cargo handling systems, pumps, and refrigeration. Shore power enables vessels to connect to landside electrical infrastructure and shut down onboard engines, resulting in significant reductions in greenhouse gas emissions and local air pollutants such as nitrogen oxides, sulfur oxides, and particulate matter. In addition to emissions reductions, shore power can improve local air quality, reduce noise and vibration, and decrease engine wear, contributing to both environmental and operational benefits in port areas.

The implementation of shore power systems requires the provision of reliable, high-capacity electrical infrastructure at the berth, including substations, transformers, and grid interconnections. Standardized high-voltage connection systems, typically aligned with IEC/IEEE 80005, enable safe and interoperable connections between ships and shore. Key system components include transformer and switchgear established at each vessel location, cable management systems, connection interfaces, and control and safety systems that ensure proper synchronization and operation during connection and disconnection. Successful deployment also depends on vessel compatibility, including retrofitting existing ships or ensuring new builds are equipped with shore power capabilities. Often most challenging, power supply and distribution to port side shore power components needs to be coordinated with the local utility.

Shore power is increasingly being adopted as a regulatory and policy-driven solution in leading port regions, supported by frameworks that mandate emissions reductions at berth and incentivize electrification. Its effectiveness is closely linked to the carbon intensity of the electricity supplied, with the greatest benefits achieved when power is sourced from renewable or low carbon generation. While implementation can involve significant upfront investment and coordination across multiple stakeholders, shore power represents a mature and scalable solution that can deliver immediate emissions reductions, particularly in high-traffic ports and regions with strong regulatory drivers. As part of a broader port decarbonization strategy, shore power plays a critical role in reducing near-term emissions while supporting longer-term energy transition objectives.

Connecting a vessel to the electricity network on shore is referred to as Shore power or Onshore Power Supply (OPS). This practice is also commonly known as cold ironing, shore-side electricity, shore connection, shore-to-ship power, or alternative maritime power. While multiple terms are used across regions and industries, the term “shore power” is adopted here for consistency.

Shore power enables vessels to connect to landside electrical infrastructure while at berth, allowing auxiliary engines to be shut down. This practice directly addresses emissions generated during port stays, which are a significant source of greenhouse gases and local air pollutants such as nitrogen oxides, sulfur oxides, and particulate matter. In conventional operations, vessels rely on onboard fossil fuel-based generators to meet power demands for cargo operations, hoteling loads, and onboard systems. Shore power replaces electrical loads; on many tankers, oil-fired boilers that raise steam for cargo pumps and heating are not replaced unless those systems are electrified, which limits the at-berth saving. Shore power replaces this with grid-supplied electricity, reducing emissions at the point of use and improving air quality in port areas and surrounding communities. Additional benefits include reduced noise, vibration, and engine maintenance requirements, contributing to improved operational conditions within ports.

As a core decarbonization measure, shore power contributes directly to reducing vessel-related emissions at berth and supports compliance with increasingly stringent environmental regulations. Shore power also supports secondary thematic areas, including energy system integration and transition readiness, as it requires upgrades to port electrical infrastructure, grid capacity, and coordination with utilities. In addition, it enables alignment with broader clean energy strategies by increasing demand for low carbon electricity and supporting electrification pathways across port and maritime operations.

The implementation of shore power has advanced significantly in several regions globally, particularly along the west coast of North America and throughout Europe. In California, shore power is being implemented at scale under regulatory frameworks such as the At-Berth Regulation, with major ports including Long Beach, Los Angeles, and Oakland deploying systems for container and cruise vessels, where operational profiles and berth times make electrification particularly effective.

Similar developments are taking place in Europe, supported by decarbonization policies, with ports such as Hamburg, Rotterdam, and Oslo implementing shore power across multiple vessel classes.

While most operational systems today focus on container, cruise and ferry vessels, shore power for tankers is operating at a few terminals, such as the Port of Gothenburg (Port of Gothenburg, n.d.a), and is being planned and evaluated elsewhere.

Feasibility studies conducted at terminals such as Valero Benicia (tankers) and Port of Everglades (cruises), which are publicly available, reach different conclusions: the Port Everglades study recommends phased shore power at its cruise terminals (Moffatt & Nichol, 2023), while the Valero Benicia study found shore power not feasible at that tanker terminal because no available cable handling system could safely serve the design vessels (Moffatt & Nichol, 2022a).

In DMCs, the adoption of shore power is at an earlier stage but is gaining interest as ports explore pathways to reduce emissions and align with international standards. Initial pilot projects and feasibility assessments have been undertaken in selected ports, particularly those with strong international trade exposure and increasing environmental expectations. However, large-scale deployment remains limited due to infrastructure constraints and economic considerations. As regional ports seek to enhance competitiveness and meet evolving requirements from shipping lines and cargo owners, shore power is expected to become an increasingly relevant solution, particularly for high-traffic container terminals and cruise facilities.

Successful implementation of shore power is supported by a well-established international standard under IEC/IEEE 80005 series, whose Part 1 (IEC/IEEE 80005-1:2019) defines high-voltage shore connection systems and whose Part 3 (IEC/IEEE 80005-3:2025) covers low-voltage systems and ensures compatibility between vessels and port infrastructure. These standards continue to evolve to reflect advances in technology and operational experience. In addition, industry guidance, including recommendations developed by OCIMF for tanker applications, provides further direction on safety, operational integration, and system design.

Despite this level of standardization, key challenges remain. The availability of sufficient electrical power at ports is often a primary constraint, requiring coordination with utilities and, in many cases, significant upgrades to grid infrastructure. Capital costs associated with shore power systems, including substations, cable management systems, and berth modifications, can also be substantial and are influenced by site-specific factors such as space constraints and safety requirements. As a result, implementation often depends on public funding, incentives, or cost-sharing mechanisms to support deployment. Addressing these challenges through coordinated planning, investment, and policy support is critical to enabling broader adoption of shore power in port environments.