Environmental Ship Index

Environmental Ship Index now includes score for carbon performance

29 May 2020

The Environmental Ship Index (ESI) added carbon performance as a new criterion on 1 July 2017. Previously, the index only weighted the environmental performance of vessels based on their sulphur oxide and nitrogen oxide emissions.

This makes the index the first sustainability standard in international shipping that includes carbon performance – and, specifically, the reduction of carbon emissions – in its scores.



The ESI draws on historical data already incorporated into the index. It compares a vessel’s fuel consumption and the number of nautical miles it has completed over the past three years (for example, 2013, 2014 and 2015) with those for the following year (2016). If the vessel consumed less fuel in relative terms – that is, having improved its efficiency – this means its carbon emissions were lower as well. ESI has opted for this unconventional method on account of how difficult it is to measure carbon emissions.



Port of Amsterdam Harbour Master Marleen van de Kerkhof: ‘Clean Shipping is one of the key elements of our Sustainable Port strategy. Our Port has participated in the Environmental Ship Index from the outset. We feel it is an important tool for us, as it rewards vessels with the best sustainability performance in a clear and transparent way: the “greener” the vessel, the higher the score. The number of vessels participating in the ESI programme has increased to 20 percent since the programme was launched back in 2011. All stakeholders get to benefit from participation: vessel operators receive a discount on their harbour dues, while the port area benefits from the vessels’ reduced emissions.’