In this paper the authors make a comparative analysis of thermopower installations operated with hydrogen and oxygen, installations appropriate to cover the daily peak loads in a power system. Comparing the type of installation having rotating motors and a gas turbine or steam turbine with an installation format of diesel engine and steam turbine, we argue the latter alternative as preferable. Here, we discuss in more detail the installation with diesel engine in which the oxygen and hydrogen obtained from water electrolysis are recombined. In order to utilize completely the steam energy resulting from this recombination after it is released from the diesel engine, this energy is used in a steam turbine with condensation. In this way the entire installation has an effective efficiency about 50% larger as compared with the former alternative cited above. Published by Elsevier Ltd.