As opposed to fuel oil, methanol can be carried in double bottom tanks since it is not considered harmful to the environment on a macroscopic level. (This does not mean that it is allowed to dispose methanol overboard as an operational procedure.) One special feature for methanol bunker tanks is that they need to be inerted, as opposed to conventional fuel oil tanks.
The SPIRETH project uses an independant transport tank container for bunker. The bunker tank is located on weather deck and is equipped with a drencher system for additional safety. Filling of the tank is done from tank truck.
For the Stena Germanica, a double bottom tank is proposed due to the significantly larger volumes of methanol needed.