To shorten the preheating time of a regenerative heat exchanger which is performed at the time of an initial start, and at the time of a cold start after routine inspection, etc., and to reduce its compressive driving force.

An MHD generation system generates a voltage between electrodes 10, 11 by supplying a working fluid 1 in which conductive seeds have been injected to an MHD generator 4; forming a closed loop for passing this working fluid from a compressor 2 back to the compressor 2 through a regenerative heat exchanger 5, a high-temperature heat exchanger 3, the MHD generator 4, the regenerative heat exchanger 5, and a cooler 6; passing a high- temperature working fluid obtained by passing it through the high-temperature heat exchanger 3 in a magnetic field generated by the electromagnets 9 of the MHD generator 4. Therefore, a by-pass pipe 12 is provided to pass by the MHD generator 4 at the time of a cold start between the high-temperature heat exchanger 3 and a regenerative heat exchanger 5.