PhD Defense - Gaël CLODIC - LHEEA/ED SPI

Gaël CLODIC will defend his PhD on Monday, June 07, 2021 at 2.00pm by videoconference on zoom and in lecture theater E (places will be very limited).

On June 7, 2021 from 14:00 To 18:00


" Analysis, modelling and optimization of an energy ship for hydrogen production "


The thesis defense will take place on Zoom:

Password: dFr51=kN

The defense will start at 14:00 am, the videoconference will be open from 13:30 am so that you can test your connection.
In order to lighten the bandwidth, all participants will be asked to switch off their camera and microphone throughout the presentation. Finally, we thank you to connect around 13:45 am or earlier in order to have time to manage any technical problems before starting the defense. Thanks to all of you!

A limited number of place will be available in Lecture Theater E.


The present thesis investigates the innovative energy ship concept for offshore wind energy conversion. In this concept, wind is used to propel a ship. Electricity is generated using water turbines attached underneath the hull. The electricity is converted through electrolysis into hydrogen which is then stored aboard. An energy ship is a complex system composed of many sub-systems.
In the first part of the thesis, a system engineering approach is used in order to develop a analysis framework for the comparison of solutions for the subsystems. A case study is conducted for the wind propulsion subsystem of an energy ship. Among the five technologies studied (soft and rigid sails, Flettner rotors, turbo-sails and kite wings), Flettner rotors are selected for an application on the energy ship.
In the second part a numerical model of the ship  is developed in quasi-static conditions. It is  based on the resolution of the equation of motion of the ship and on a potential flow method for the hydrodynamic part of the model. It shows that an energy ship with a catamaran hull of 80 m long is able to produce an electrical power of 1 MW in a 10m/s beam wind. This electrical power is equivalent to a weekly production of 2.9 tons of hydrogen. The nominal power of the ship (1.73 MW) is achieved at a wind speed of 12 m/s.
In the last part, hull optimization is performed  using a genetic algorithm (NSGA II). The purpose is to maximize the energy production. Both symmetrical and non-symmetrical catamaran shapes are generated. Results show that non-symmetrical shapes, similar to "proa" ships, achieve the best efficiency. A gain of 15% of power production is obtained compared to the previous results (equivalent to a weekly production of 3.3 tons of hydrogen).
Published on May 31, 2021 Updated on June 8, 2021