The superyacht industry has been lacking an objective way to judge if and how some yachts and new concepts are indeed better than others when it comes to environmental credentials. Since March 2019 a joint industry project group existing of major shipyards, naval architects and knowledge institutes have been collaborating through Water revolution Foundation to develop the Yacht Environmental Transparency Index (YETI).

Project chair & initiator Bram Jongepier:
“I’m very proud of the level of cooperation and sharing of knowledge within the YETI group. This collective effort will lead to a better understanding of how to decrease energy demand, raise system efficiency and ultimately stimulate reducing environmental impact.”

Sharing progress
The YETI project group now wishes to share its progress with the yachting community. While YETI is still under development, we inform about our approach, scope, research conducted and decisions made. We welcome and encourage peer-reviewing. Only together and through a pro-active approach we can accelerate sustainability in yachting and future-proof the busines.

Approach & scope
YETI is based on Life Cycle Approach. The current scope of YETI is focusing on the operational profile of the yachts, and in particular the energy it uses. This mainly exists of energy for propulsion and hotel. An average operational profile has been compiled that is applicable to all yacht types, from fast motor yachts to sailing yachts. By combining all yachts in one scope, we can truly compare yachts with one another on their environmental credentials.

Sailing profile
The YETI test fleet existed of 130 yachts submitted by the participating shipyards. From these yachts a total of 297 years of AIS data was purchased to analyse the yachts’ real behaviour on a yearly basis. Combining this information with the yacht specific data, we determined the average energy used for propulsion, including the correction for the use of sails.

Hotel load
Besides the propulsion, an important part of the yachts’ energy use goes into the hotel function. This is however tough nut to crack, as electric load balances are often theoretical calculations and there is very little monitoring data from real hotel loads available. The YETI group is comparing load balances to see what the commonalities are and where there are differences. These variable categories is where bonus points can be gained. Hotel energy can come from generators or shore power, both are incorporated. To determine shore power, a marina survey on availability, a captains’ survey on common practice, and an environmental study into the energy grids of most popular yachting regions have been conducted, to know the amount of shore power used and the environmental impact.

Environmental impact
After having determined the average operational profile of the yacht, the emissions can be calculated, and as such the environmental impacts. These impacts are accumulated into a single score: ecopoints.

Functional unit
After calculating the ecopoints, and in order to make the comparison between the yachts, it needs a denominator. A verifiable functional unit of luxury is needed, currently the consideration is to select Gross Tonnage, yet other options are being reviewed. Ultimately, the challenge is to provide the same experience to clients, by using less resources. Efforts for using less resources are rewarded in the YETI score.

Call to action
More data is needed to re-confirm the determined operational profile. Especially additional data on fast and sailing yachts is welcome increase accuracy. A peer-review group will be compiled to test and verify the developed calculation method.

Learn more about YETI.