Ports worldwide are under increasing pressure to demonstrate environmental leadership, improve air quality, and contribute to decarbonisation efforts across the maritime value chain. The Environmental Ship Index (ESI) has become the world’s leading port incentive scheme, providing ports with a structured and internationally recognised framework to incentivise ships that perform beyond regulatory environmental standards.
Today, more than 100 ports across five continents participate in ESI. There are good reasons for this growing adoption.
Governed by IAPH and Aligned with Global Standards
The Environmental Ship Index is governed by the International Association of Ports and Harbors (IAPH) and has been fully integrated into IAPH’s governance structure.
This ensures that:
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The scheme is industry-led
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It remains neutral and non-commercial in character
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It continuously adapts to technological and regulatory progress
For ports, this provides credibility and alignment with global maritime sustainability initiatives.
Supporting Clean Air and Scope 3 Emissions Transparency
Ports increasingly focus on improving local air quality and addressing Scope 3 emissions from vessel calls.
ESI enables ports to:
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Recognise environmental performance beyond mandatory regulation
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Incentivise cleaner vessels through structured schemes
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Signal active commitment to clean air policies
Rather than prescribing emission reduction targets, ESI provides a harmonised framework that ports can integrate into their own sustainability strategies.
Over time, broader adoption of ESI across ports strengthens the economic case for shipowners to invest in cleaner technologies.
Increasing Visibility and Attractiveness
More than 6,800 vessels are registered in the Environmental Ship Index.
By participating in ESI, ports position themselves within a global network recognised by shipping companies that actively manage environmental performance.
This can:
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Increase visibility among environmentally focused operators
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Enhance the port’s sustainability profile
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Support stakeholder communication efforts
Participation signals alignment with internationally recognised environmental standards.
Structured and Flexible Incentive Design
ESI does not impose uniform incentive structures.
Each port defines its own scheme, typically in the form of:
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Port due discounts
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Fee reductions linked to ESI score thresholds
Ports retain full flexibility while relying on a consistent and independently calculated scoring system.
OceanScore, as the mandated administrator of ESI, collects and verifies vessel data and calculates ESI scores, which are then communicated to participating ports on a regular basis.
This centralised administration ensures:
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Transparency
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Consistency
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Reduced administrative burden for ports
Additional Benefit: PortView Integration
Participating ports receive a discount on OceanScore’s proprietary PortView solution.
PortView provides:
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Emissions baselines for vessels calling at the port
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Continuous tracking by vessel and port area
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Structured data insights supporting environmental reporting
Together, ESI and PortView provide both incentive mechanisms and emissions visibility.
A Growing Global Network
With more than 100 ports across five continents, the Environmental Ship Index has established itself as the leading port incentive framework globally. As more ports participate, the collective impact increases, strengthening incentives for cleaner vessels and supporting healthier port communities.
Is Your Port Ready to Join?
The Environmental Ship Index offers ports a structured, internationally recognised framework to incentivise cleaner air and environmental performance beyond regulation. To learn more about how the Environmental Ship Index works for ports, visit our dedicated page.
