ÈTA’s efficiency lies in the reduction of the need for energy, autonomy, predictable maintenance and a much simpler engine room. There is no main engine, but an electric motor for which three diesel generators are currently available. We can easily change over to other fuels, such as ammonia or methanol. Moreover, it is possible to plug in a container with any sustainable power source, for example hydrogen. This makes it practicable to sail completely or partially emission-free without generators. It is also possible to plug in a small fuel cell, so that we can enter the port emission-free or lie at the dock emission-free.