In January and March 2022, the guarantee measurement (GM) of the unit TG6 at the Stejaru hydroelectric power plant in Romania was carried out in two phases for two different heads (125 m and 120 m). After lengthy discussions with the plant operator, the thermodynamic method was chosen as the primary method of efficiency measurement given the condition of the old penstock.

It was a rather demanding measurement under the strict supervision not only of the plant operator and the turbine supplier, but also of an independent consultant from the Swedish company Sweco. In addition to the energy parameters, the GM was also subject to verification of unit vibration.

As well as the measurements, the evaluation and subsequent technical report were subjected to rigorous scrutiny by all parties involved. To the general satisfaction, the measurements showed that all guaranteed values for efficiency, maximum power, vibration and other verified parameters were met.