The TE-TO Osijek power station, a combined heat and power (CHP) plant in Croatia, faced a critical challenge. Specifically, the management of three hot water circulation pumps within the central heating system proved to be unreliable due to frequent breakdowns and difficult maintenance. Downtime and repairs led to increased costs and operational inefficiencies. By using frequency-regulated electric motor drives in thermal power plants, significant energy savings can be achieved at the same time carbon dioxide emissions can be reduced. In addition to the above generally accepted practice of replacing part of unregulated electric drives with regulated ones, there is also a tendency to replace old engines with low energy utilization by high efficient modern engines with a high energy class often classified according to IEC standards. The customer Hrvatska elektroprivreda d.d. (HEP Group) decided to install one frequency regulated electric motor operation of the circulation pump in the central heating system of the city of Osijek to enhance plant reliability and reduce maintenance burdens.