Abstract: An electricity generating device comprising a housing; a first lobed rotor and a second lobed rotor rotatably arranged in a fluid passage enclosed by the housing such that the lobes of the first and the second lobed rotor intermesh to create a barrier between a high-pressure and a low-pressure side of the housing during operation of the device; a first electricity generator to which the first lobed rotor is coupled, the first electricity generator being capable of varying the load of the first lobed rotor; and a second electricity generator to which the second lobed rotor is coupled, the second electricity generator being capable of varying the load of the second lobed rotor. There is also provided a method of synchronizing rotational positions of a first lobed rotor coupled to a first electricity generator and a second lobed rotor connected to a second electricity generator in a turbine.