The vessel (1) has a water storage chamber provided with a terminal for receiving water and another terminal for a water inlet. An electricity generation unit (5) comprises a generator (7) and a turbine (6), where the turbine supplies external produced vapor over a steam pipe (20). A capacitor (8) is integrated in the vessel for condensation of the vapor under delivery of warmth to water (2) i.e. cooling water. The generator and the turbine are arranged in a closed component that partially surrounds an insulating material for an acoustic insulation.
