Policy Recommendation: Marine Electrification to Improve Air Quality in Hong Kong

Photo by Kinsey Wan, Unsplash.

Policy Recommendations to Environment and Ecology Bureau and Transport and Logistics Bureau 

Clean Air Network (CAN) expresses its support for the HKSAR Government’s commitment to reinforce Hong Kong’s position as an international maritime centre. as it could potentially bring environmental and health benefits to the general public. 

The Action Plan on Maritime and Port Development Strategy, published by the Transport and Logistics Bureau in 2023, set out the strategic vision to establish Hong Kong as a green shipping fuels trading and bunkering hub, includes supplying low-and-zero-carbon fuels, such as green methanol and to serve as a node in international and regional green shipping corridors. Specifically, the Direction (1): Enhancing Port Competitiveness – Strategy (1): Developing Hong Kong as a Green Shipping Hub towards the Goal of Zero-Carbon Emission demonstrates the ongoing commitment on decarbonization and presents an opportunity for further reduce emissions in Hong Kong. 

Given the latest development of global shipping industry to become greener and cleaner, Clean Air Network emphasizes the need for the HKSAR Government to consider Marine Electrification, comprising Onshore Power Supply (OPS) and Electrification of Harbour Craft, as a vital strategy to further improve air quality and reduce public health risk in Hong Kong.     

Current Air Quality in Hong Kong

Over the past 20 years, Hong Kong’s overall air quality has been improved significantly and broadly complied with Hong Kong’s Air Quality Objectives (AQOs). From 2004 to 2024, the annual average concentrations of respirable suspended particulates (PM10), fine suspended particulates (PM2.5), nitrogen dioxide (NO2) and sulphur dioxide (SO2) in the ambient air have reduced by 45% to 88%.  

Despite notable progress, general station monitoring data reveals that there were significant variations in annual NO2 concentrations in 2023 ranging from 8 μg/m3 to 50 μg/m3 (see Annex 1), among which three stations fell short of the AQO for annual NO2. The highest levels were recorded in Kwai Chung, an area with key port facilities, suggesting that these elevated concentrations could be attributed to emissions from marine shipping activities.

This poses a serious public health risk to residents and workers exposed to high level of air pollution over prolonged periods, increasing their vulnerability to cancers and a range of respiratory and cardiovascular diseases. 

Currently there is no specific legislation in Hong Kong regulating nitrogen oxides (NOx) emissions from ships, marine electrification presents a viable solution to improve air quality, especially in the vicinity of the port. 

Combating Marine Vessel Emissions through Marine Electrification 

Shipping remains to be the largest local emission source of NOx, PM10, PM2.5, and the second largest source of SO2 and carbon monoxide (CO). 

Local (including government fleets) vessels and river vessels (herewith “harbour craft” collectively) account for about 60% of NOx and 50% of PM10 of total maritime emissions in Hong Kong, or 19% of NOx and 11% of PM10 of the total HKSAR emissions. 

Ships often keep their auxiliary engines running while docked to power onboard systems, resulting in significant emissions. Emissions at ports and anchorages may account for approximately 10%–25% of total maritime emissions. In particular, emissions of cruise ships in Kai Tak Cruise Terminal with their low-level plumes greatly impact occupants in nearby high-rise buildings. 

Harbour craft, though having much lower engine power, could contribute disproportionately. For example, in California, tugboats constitute just 7% of commercial harbour craft but are responsible for 19% of PM2.5 and 23% of NOx emissions in the maritime sector. Many of these vessels use outdated engines that emit up to 162 times more diesel particulate matter than modern land-based engines. Similar and probably worsened situation applies to Hong Kong as shown in high percentage of harbour craft emissions for total marine emissions, with higher activity and lower emission standards than that of California. 

In a dense city like Hong Kong, with port operations located near residential and commercial zones, cutting SO2, NOx, and particulate emissions translates directly into improved air quality and lowered public health risks. 

Marine electrification, including onshore power supply (OPS) for ocean-going vessels (OGVs) and electrification for harbour craft, is a vital strategy for reducing total HKSAR emissions.  

Global Trends and Increased Demands for OPS

OPS Infrastructure investment by global governments has become a focus for emissions-free operation on OGVs while at berth. Increasingly, Mainland China and countries in European Union (EU) are mandating ships to be connected to OPS while berthed. This includes both cargo and cruise ships, which both produces significant emissions and pollutants from their engines while docked in close vicinity to high populated urban areas.

Regionally, both the Mainland China and EU’s ports already have widespread implementation of OPS. China’s 14th Five-Year Plan (2021-2025) sets a target of 100% shore power coverage for cruise ship terminals by 2024 and aims to achieve 90% shore power coverage for key container ship terminals by the end of 2025. Currently, there are more than 400 berths across 21 costal ports in the Mainland China providing OPS. Majority of European ports aiming to offer OPS facilities by 2030. 

Shipping and cruise companies continue to retrofit vessels to accept shore power and with the order book of new build ships reflecting a strong trend towards shore power compatibility in response to International Maritime Organization targets and new emission penalties. 

Without a clear OPS development strategy, Hong Kong risks being bypassed by newer, OPS-enabled ports and becoming a destination for older, higher-emitting ships. 

It is estimated that OPS installation would bring significant air quality improvement. At Kai Tak Cruise Terminal, use of OPS could save around 1,520 tons of fuel and eliminate 15.2 tons of SOx, 76.1 tons of NOx, and 4.9 tons each of PM10 and PM2.5 annually. In Kwai Chung Container Terminal, use of OPS could reduce 617 tons of SOx, 2,128 tons of NOx, 159 tons of PM10 and 146 tons of PM2.5 each year. 

By removing near-port emissions, OPS deployment would significantly reduce levels of air pollution and relevant public health risks. Based on the latest development, the HKSAR Government should re-assess the economic, environmental and public health potentials and formulate OPS development strategy. 

Electrification of Harbour Crafts and Domestic Vessels

Technology for zero-emission propulsion is increasingly available and viable for short-distance routes for harbour crafts and domestic vessels. Electrification of harbour crafts and domestic vessels would significantly reduce the emission. 

Currently, there are barriers including limited shore charging infrastructure and high upfront capital costs of battery-electric system. With appropriate Government intervention and a clear policy direction, such barriers should not be insurmountable. 

For example, as part of the Clean Air Plan 2035, the HKEPD has initiated a 24-month Pilot Scheme for Electric Ferries in 2025. An assessment of environmental benefits, technical performance and cost effectiveness will be conducted. The findings of the assessment should provide a basis for the Government to formulate planning for wider adoption of electric ferries and other types of vessels. 

In addition to use green methanol for decarbonization, the Government should also consider electrifying part of its fleet to demonstrate feasibility. 

Further Research Needed to Quantify Air Quality Benefits  

The Hong Kong University of Science and Technology (HKUST) has developed a bottom-up, carbon and emissions quantification tool to estimate shipping emissions and expertise in air quality modelling, with publications in top-tier international journals. Since 2006, its research has provided critical evidence for policymaking in Hong Kong and the GBA, supported scenario evaluation for the Environmental Protection Department. 

The above discussions of marine electrification are based on IMO or California information. We understand that local studies on marine emission inventory (including OGVs to/from the GBA transiting Hong Kong and river vessels calling Hong Kong) had not been carried out for some years during which shipping has undergone great changes.

To accurately quantify the air quality benefits will require detailed research. Researchers must obtain more precise emission factors for ships and use advanced pollution models, factoring in meteorology and atmospheric chemistry specific to Hong Kong, to produce robust estimates of how marine electrification would improve air quality. 

Roles of the HKSAR Government and Collaboration with Greater Bay Area (GBA) Authorities

Unlike PM pollution, which requires cross-boundary coordination with Guangdong due to its transboundary nature, most shipping emissions fall entirely within Hong Kong’s jurisdiction. Thus, the HKSAR Government holds full authority and responsibility to implement effective policies on OPS and upgrade local vessels.

With an increasing number of ocean-going vessels calling at Shenzhen and Guangzhou ports transit through Hong Kong waters, Hong Kong also handles frequent river cargo vessels and passenger ferries operating between Hong Kong, Macau, and Guangdong ports. Given these cross-boundary vessel movements and the emissions produced, regional cooperation among the three jurisdictions is crucial to effectively address air pollution and climate impacts

Policy Recommendations

With the overall goals to further improve air quality and reduce public health risk in Hong Kong, Clean Air Network proposes the following policy recommendations: 

  • Formulate an OPS development policy and timetable for implementation 
    • The Environment and Ecology Bureau should lead to develop a clear policy direction that enhances infrastructure readiness, and provide the regulatory leadership necessary for retrofitting berths, investment in transformers and substations, coordination with power grids.  
  • Formulate strategy on electrification of vessels  
    • The Environment and Ecology Bureau should lead to formulate strategy on electrification of harbour craft and domestic vessels including provision of shore charging infrastructure and accelerate adoption, apart from subsidizing trial of electric ferries. 
    • The Government should also formulate a roadmap with clear time frame to electrify its marine fleet to reduce its emission and demonstrate support for electrification. 
  • Establish regional coordination on marine emissions 
    • The Environment and Ecology Bureau should initiate conversations with GBA Authorities with a view to formulate a regional emission strategy. Given cross-boundary vessels operations between Hong Kong, Macau, and Guangdong, it is beneficial for the GBA Authorities to develop a strategy to advance vessel electrification, coordinate incentives, plan infrastructure for alternative fuels. 
    • The Transport and Logistics Bureau should collaborate with other GBA and global ports to align protocols for green corridors. 
  • Advance research on quantifying marine emissions 
    • The Environmental Protection Department should formulate a research to obtain precise emission factors for ships to quantify changes on air quality due to various policy measures. 

Acknowledgement

We gratefully acknowledge the sharing of data provided by the Hong Kong University of Science and Technology to support development of this submission.

For detailed statistics, please view the PDF here.