Abstract: In a gas supply pipe section, an asynchronous motor generator unit is provided in a pipe section consisting of a single supply pipe upstream (at the high pressure side) and adjacent to a separating wall including nozzles for the decompression of the gas. The motor/generator unit includes a shaft which carries downstream (at the low pressure side) of a separating wall adjacent the nozzles at least one bladed turbine wheel which is of lightweight design and is driven by the gas flow. Means are provided for conducting away the electric energy generated during generator operation of the asynchronous motor and for feeding it into an energy supply net. Also, a control unit is provided which supplies a control signal to a safety valve disposed upstream of the asynchronous motor/generator unit for controlling the gas supply to the pipe section when the speed of the shaft exceeds a critical speed value.