The invention relates to a method for controlling ORC stacks with a total number ntot of individually operable ORC modules, said method comprising the following steps: determining the running time remaining until the next servicing time for each operable ORC module respectively; determining a target number nsoll of ORC modules to be operated; comparing said target number nsoll to an actual number nist of currently operated ORC modules; when nsoll>nist, connecting a number nsoll−nist of ORC modules that corresponds to the difference between the target number and the actual number, where the ORC modules with the longest remaining running times of the ORC modules currently not being operated are connected; and/or when nsoll Δt2.