The TCV tokamak is powered by a flywheel generator to supply the magnetic coils and the auxiliary heating systems. The generator has just undergone its fourth major overhaul to make it ready for the next ten years, after more than thirty years of almost trouble-free operation. In the context of the energy crisis in Europe, we took advantage of the generator outage to evaluate the power consumption of the TCV power supply system and to implement some changes to increase the energy efficiency. After a presentation of the operation history and a brief description of the operating mode, this article presents the work and the findings of the generator overhaul. Then, the changes implemented in the generator plant are discussed in terms of reducing the energy cost and improving the availability of the TCV experiment.