EEDI – what is it?

EEDI stands for Energy Efficiency Design Index. In July 2011, the International Maritime Organization’s (IMO) Marine Environment Protection Committee (MEPC) adopted mandatory measures to reduce Greenhouse Gas (GHG) emissions from international shipping through amendments to MARPOL Annex VI Regulations. These amendments include application of the EEDI for new ships which will require new ships to meet a minimum level of energy efficiency from 1 January 2013.
The EEDI measures the CO2 emitted (grams of CO2 per tonne nautical mile) for new ships, calculated from ship design and engine performance data. The intended application of the EEDI is to stimulate innovation and technical development of all elements influencing the energy efficiency of a ship from its design phase.

If the EEDI was designed for new vessels, can it be applied to existing ships?

The Denmark paper that initially proposed the EEDI to IMO’s MEPC stated that "it is not inconceivable that design indices or equivalent may be applied retroactively to existing ships." The IMO have now documented EEDI benchmarks and reference lines based on the existing fleet and historical data.

RightShip has developed the EVDI™ to address the 70,000+ vessels currently in service, which annually contribute over 1 billion tonnes of CO2 to the atmosphere.

EVDI™ – what is it?

EVDI™ stands for Existing Vessel Design Index and was developed by RightShip. The EVDI™ is the core measure used to calculate the GHG Emissions Rating and is comparable across all vessels in RightShip’s Ship Vetting Information System (SVIS™) database.

Similar to the IMO MEPC’s EEDI, RightShip’s EVDI™ measures a ship’s CO2 emissions per tonne nautical mile travelled based on the characteristics of the ship. However, unlike the EEDI that is applied only to new ships from 1 January 2013, the EVDI™ is designed for application with existing ships.

A comprehensive explanation of RightShip’s method is accessible here

EVDI™ Size Score – what is it?

The EVDI™ Size Score is the measure used to determine a vessel’s GHG Emissions Rating.

The EVDI™ Size Score is calculated using logarithmic transformed (normalised) EVDI™ values of vessels of similar size and type. Normalised data is required for accurate comparison to the average. The EVDI™ Size Score represents a comparison of a vessel’s normalised value to the mean normalised values of vessels of similar size and type.
A comprehensive explanation of RightShip’s method is accessible here

GHG Emissions Rating – what is it?

The GHG Emissions Rating is an innovative measure developed by RightShip and Carbon War Room that allows comparison of a ship’s CO2 emissions relative to peer vessels of a similar size and type using a simple A - G scale.  The most efficient vessels are rated A, the least efficient are rated G. Ship types are largely consistent with those used by IMO MEPC. A comprehensive explanation of RightShip’s method is accessible here




Why has the GHG Emissions Rating been developed?

Shipping impacts the environment through emissions of greenhouse gases (GHG) - primarily carbon dioxide (CO2) - and pollutants such as nitrogen oxides (NOx), sulphur oxides (SOx) and unburnt hydrocarbon particulate matter (PM).

While transporting goods by sea represents the most efficient means of moving cargo over long distances, air pollution from the shipping sector still represents a significant component of total emissions - estimated at 949 million tonnes of CO2 in 2012 (some 3.1% of the global total). According to the IMO’s GHG Study (2009), if unabated, shipping could contribute 18% of all emissions by 2050.

This GHG breakdown does not divide into all ships equally and considerations such as ship size, fuel type and engine performance, as well as advances in maritime technology, mean that some ships are simply more efficient than others.

Recognising that vessel specific sustainability information is dispersed and costly to obtain and coordinate in a systematic manner, RightShip and Carbon War Room created the GHG Emissions Rating to make it easy for shipowners, operators, charterers, shippers and financiers to consider sustainability within their selection processes.

What are the benefits of the GHG Emissions Rating?

The benefits of GHG Emissions Rating include:

- Rewards for sustainable operators through greater acceptance of their ships

- Fast and easy access to data that has previously been dispersed & prohibitively costly to gather

- Opportunity for customers to align vessel selection with their sustainability standards

- Opportunity for customers to reduce bunker cost

- Promotion of sustainable outcomes for RightShip customers and the wider industry

- Better informed decisions

- Users will also be able to benchmark the ship they are viewing against others in its sub-class. For example, by comparing vessel specific statistics with other vessels with a similar dead weight tonne (DWT)

Size and Type GHG Emissions Rating – what is it?

The Size and Type GHG Emissions Rating considers the efficiency of a ship relative to other ships of the same type and similar size, and the efficiency of the vessel overall within the ship type. This is different to the EVDI™ Size Score that only considers ships of the same type and similar size.

A comprehensive explanation of RightShip’s method is accessible here

How do RightShip customers use the GHG Emissions Rating information?

RightShip customers are using the information to support their company sustainability objectives. Early adopters of the technology have the opportunity to identify the most energy efficient vessels on the market to meet sustainability targets while reducing their bunker cost.

What does it mean if a vessel has a G rating?

The A to G rating is a measure of relative efficiency and is based on the EVDI™ Size Score. The EVDI™ Size Score is calculated after applying a logarithmic transformation to EVDI™ values of vessels of similar size and type. A vessel with a G rating is more than 2 standard deviations less efficient than the mean score of other vessels of similar size and type.

How can I improve my GHG Emissions Rating?

Vessel owners who are not RightShip customers should logon to shippingefficiency.org to check the vessel design particulars used by RightShip and undertake the following:

Ice-class vessels have design and structural features that increase their estimated EVDI™ relative to similarly-sized conventional vessels. Until suitable correction factors can be developed and applied, the EVDI™ for ice-class vessels is likely to overstate the actual CO2 output.

What upgrades or retrofits will help to improve my vessels GHG Emissions Rating?

There are a raft of retrofits and upgrades that may help to improve your vessels GHG Emissions Rating. These include changes to ship design, propulsion and machinery. A full list can be viewed by creating an account in www.shippingefficiency.org and selecting to add a retrofit.

Is a newer vessel more efficient than an older vessel?

It is a pre-conception that newer is always more efficient. While the technology is available to build a more efficient vessel, this technology is not always applied to every new vessel built.

EEOI – what is it?

EEOI stands for Energy Efficiency Operational Indicator and provides a measure of the mass of CO2 emitted per unit of transport work based on a vessel’s actual operational data. Unlike the EEDI and EVDI™, the EEOI will change depending on how the vessel is operated and what abatement measures the owners/managers have retrofitted.

RightShip plan to incorporate the EEOI at some point in the future and the SVIS™ database has been structured to enable easy comparison of EEOI & EVDI™ figures.

How does slow steaming impact the GHG Emissions Rating?

Slow steaming will not impact a vessel’s EVDI™ and consequently will not impact a vessel’s GHG Emissions Rating.

The GHG Emissions Rating is calculated based only on a vessel’s design specifications and therefore is not impacted by the way the vessel is operated.

RightShip adjoin a plus + Sign to a vessel's GHG Emissions Rating to recognise a retrofit or upgrade.

If I know how far a vessel is travelling can I work out an exact footprint based on the information in your website?

EVDI™ is an estimated measure of the CO2 emitted per tonne nautical mile travelled only and will not produce an exact CO2 footprint for a particular journey.

Actual emissions for a voyage will vary from this theoretical calculation, as the fuel consumption and consequent emissions will vary with voyage characteristics such as actual speed, cargo load and weather conditions.

RightShip plan to incorporate the Energy Efficiency Operational Indicator (EEOI), an indicator based on operational measures, including slow steaming, at some point in the future.

Top Rated Peers – what is it?

Top Rated Peers shows the five highest performing vessels as hyperlinks based on EVDI™ Size Scores for vessels of similar size and type. Clicking on one of these vessels allows a performance differential between the original vessel and the most efficient vessels of a similar size and type.

How are "like vessels" grouped in the GHG Emissions Rating?

The vessels are grouped by ship type and compared to the closest 50, 100, or 200 vessels in that class by dead weight tonne (DWT), gross tonnage (GT), twenty foot equivalent unit (TEU) and cubic metres, depending on vessel type to get a more representative rating.

Does your rating treat all vessels equally?

The GHG Emissions Rating and the Size and Type GHG Emissions Rating are calculated in the same systematic manner for all vessels in the database. However please note:

LNG and Passenger Vessels: The EEDI, as presently constructed, is not designed or intended for application to LNG and passenger vessels which have diesel-electric, turbine, and other non-conventional means of propulsion. It is anticipated that the IMO will develop refined parameters, formulas, and reference baselines for these ships in the near future. Accordingly, any attempted evaluation of this type of ship using the EVDI™ should be understood to be outside of the effective purpose of the index.

Ice Class Vessels: Ice-class vessels have design and structural features that increase their estimated EVDI™ relative to similarly-sized conventional vessels. Until suitable correction factors can be developed and applied, the EVDI™ for ice-class vessels is likely to overstate the actual CO2 output.

The separation of Gas and Chemical tankers: The EEDI currently combines the performance of Gas Tankers into a single reference line. Based on the bimodal distribution of the underlying data, RightShip believes a better statistical comparison can be achieved by analysing LNG and LPG Tankers separately. Chemical tankers are similarly considered separately from other Tankers (Crude & Products) to acknowledge different design characteristics.

What is the reason why some sister ships have different ratings?

A vessel’s EVDI™ value is based on many parameters and if one of these parameters differs between sister ships they could have a different EVDI™, moving them into a different rating bracket. The base data used in the rating calculation of an individual vessel is provided in SVIS™, so the source of differences between sister ships can be checked.

The GHG Emissions Rating seems to focus on Carbon Dioxide, what about other Greenhouse Gases?

RightShip plan to incorporate metrics around a number of pollutants such as nitrogen oxides (NOx), sulphur oxides (SOx) and unburnt hydrocarbon particulate matter (PM) as well as real time performance measures.

Can I rely on the information RightShip have?

RightShip endeavours to only use accurate source data and our calculations are in accordance with those accepted by the IMO for their application of the EEDI.

Our approach largely uses the same data set recognised by IMO MEPC in their establishment of an EEDI “reference line” for new ships.

We encourage all vessel owners to review the vessel design particulars used by RightShip to calculate the EVDI™ by logging on to SVIS™. For vessel owners that are not RightShip customers, this data can be freely viewed on www.shippingefficiency.org

Feedback on any retrofits, upgrades, inaccuracies or inconsistent information on your vessel can be provided through www.shippingefficiency.org or by emailingenvironment@rightship.com

Where does RightShip get its information from?

EVDI™ values are calculated from data on ship characteristics that is accessible to RightShip. To date the primary sources of data have been existing data within SVIS™, IHS Maritime (IHS) database, owners and operators, classification societies, yards and engine manufacturers. RightShip’s vessel owner community has the opportunity to preview our information and validate that the data we maintain on their vessels is accurate and up to date. As with our existing risk rating, RightShip welcome feedback on any missing/additional/inconsistent information directly through the SVIS™ portal or via environment@rightship.com

What if information on my vessels is incorrect or missing?

As with our existing Risk Rating, RightShip welcome feedback on any missing/additional/inconsistent information directly through the SVIS™ portal or via environment@rightship.com

What is the relationship between the Carbon War Room’s www.shippingefficiency.org website and RightShip?

Founded by Sir Richard Branson, the Carbon War Room is a global, independent, not for profit NGO which seeks to accelerate the adoption of business solutions that reduce carbon emissions at gigaton scale and advance the low-carbon economy. RightShip is leading the charge in the campaign against carbon within the shipping transport sector– via the Shippingefficiency.org website - and provides the backend support to this free initiative.

Subscribers to the RightShip system are able to access an enhanced version of the metrics provided to the Shipping Efficiency website to better recognise behaviours and operations which are above compliance. A customer’s own vetting histories automatically capture a vessel’s environmental particulars to enable sustainability benchmarking performance and trending analytics to be calculated.

For additional information please refer to: www.carbonwarroom.com .

EVDI Background


While international shipping is the most carbon efficient mode of commercial transport, total emissions are comparable to those of a major national economy, necessitating emission reduction. From 2007-2012, shipping was estimated to have emitted 3.1% of global CO2 emissions, of which international shipping contributed 2.2% or around 796 million tonnes. Moreover, according to the International Maritime Organization’s (IMO) 3rd Greenhouse Gas (GHG) Study, if unabated, shipping’s emissions could rise by between 50-250% over the period up to 2050. 

Policy Update: EDDI

The latest IMO measures to regulate the efficiency of new ships entered into force on 1 January 2013, making the Energy Efficiency Design Index  (EEDI) mandatory for new ships.  Essentially, the EEDI is a performance-based mechanism, thus allowing the industry to choose which technologies to use on a vessel-by-vessel basis to meet minimum standards.   

But What About Existing Ships?

The IMO should be commended for developing the EEDI, the first ever mandatory global greenhouse gas reduction regime for an international industry sector. However, as the EEDI applies to new ships built after 1 January 2013, it does not address the existing world fleet of 70,000 vessels that currently emit over one billion tonnes of carbon dioxide annually. Given the typical 25 year lifecycle of a vessel, it has been estimated that less than 15% of the fleet will be subject to EEDI certification by 2020 (IMO, 2011).   

This is where the EVDI™, ShippingEfficiency.org and RightShip step in.  ShippingEfficiency.org and RightShip developed the EVDI™, to measure a ship's theoretical CO2 emissions.  The system contains efficiency information on over 76,000 vessels including the majority of the world’s container ships, tankers, bulk carriers, cargo ships, cruise ships and ferries.  ShippingEfficiency.org aims to encourage investment, development and installation of energy efficiency technology to improve the efficiency of the fleet, by providing transparent data to the wider market. 

How This Tool is Useful to You

Use by Charterers and Shippers

Charterers can implement a policy that excludes inefficient vessels, commonly F- and G-rated vessels. This can yield significant savings since charterers pay the bulk of the fuel bill for a vessel and that this fuel bill is a large portion of charterer’s overall costs. Shippers can also use the GHG Emissions Rating to ensure minimum energy use throughout their supply chain.

With an improved understanding of the design efficiency of the vessels you charter, you can also work with shipowners to apply multiple energy efficiency technologies that deliver double-digit fuel savings. A number of charterers have amended their existing charter party agreement to include a “shared savings retrofit clause” in which the charterer and owner share the financial cost and benefits that result from applying such technologies.

Following Cargill, Rio Tinto and BHP Billiton’s examples, 39 charterers representing over 20% of the global maritime fleet has employed policies in which they exclude F- and G-rated vessels.

Use by Owners and Operators

Ship owners, operators and managers can use the GHG Emissions Rating to see how energy efficient their vessels are relative to similar vessels. This gives you an impression of how your vessels are performing. Through a series of case studies that we have developed, owners and operators have also revealed how the application of multiple energy efficiency technologies has delivered fuel savings, increased reliability and increased attractiveness of their vessels to charterers.

While not currently standard practice under the rating, it is possible to improve your rating by applying such technologies. For instance, tanker operator Odfjell retrofit 20 of their vessels with multiple technologies delivering over 20% fuel savings. These vessels have been upgraded from D to A+ in the GHG Emissions Rating. Carbon War Room has developed a series of case studies highlighting the work of industry leaders to implement these upgrades.

Use by Ports

By using the GHG Emissions Rating, ports and terminals can position themselves as environmental leaders by providing discounts, incentives or recognition to efficient vessels. You are also able to use the Rating to set targets for your port’s environmental performance.

Port Metro Vancouver’s EcoAction Program and Port of Prince Rupert’s GreenWave program offer discounted harbour dues to efficient vessels based on the GHG Emissions Rating and other environmental metrics.

EVDI Method

For information about the method, please refer to RightShip’s website.