@hannah I have been there and it is a marvel!

They only need a 3 kW electric motor to run this.

Why?

Because of the Archimedes principle, each boat entering a pod pushes away the same amount of water as the ship weighs - as each pod is always filled with water up to the top - that means the whole setup is ALWAYS balanced - so you only need to overcome the friction of the huge gears of that many tons weighing device!