Restoring stability and performance to a hydropower turbogenerator

RES’ Hydro team in Spain delivered a high-precision corrective intervention on a 40MW hydropower turbogenerator. This restored stable operation following elevated vibration levels identified during routine monitoring and confirmed through on-site measurements.

The challenge

In March 2025, RES was engaged to support a 40MW hydropower plant after the client suspected that vibration levels in a key turbogenerator may have exceeded acceptable operating limits.

To confirm this, the client carried out on-site measurements, which verified abnormal vibration behaviour in the unit and indicated the need for further specialist assessment.

Both the client and RES operations teams reviewed the findings. Following this assessment, RES was commissioned beyond the existing scope of works to carry out a major corrective intervention.

The objective was to identify the root cause of the issue, restore safe and stable operation of the unit and ensure continued plant availability.

The solution

RES was appointed to carry out a major corrective intervention beyond the scope of its existing activities at the site.

A two-week analysis phase was undertaken, during which the Hydro team reviewed operational data and SCADA readings, supported by on-site measurements to assess vibration and alignment conditions.

This assessment identified misalignment in the turbine-generator assembly as the root cause of the issue.

To resolve this, RES executed a carefully planned intervention over approximately six weeks, including partial disassembly of the unit, overhaul and replacement of critical components, and high-precision realignment using specialist equipment. All works were delivered under strict safety protocols within a live operational environment, ensuring continuous plant availability throughout.

The impact

Following the intervention, vibration levels were reduced to within OEM tolerances, restoring stable and reliable operation of the turbogenerator.

The unit’s operational performance was reinstated with full confidence in its continued safe operation. Importantly, the intervention was completed without any loss of production, ensuring uninterrupted generation throughout the works.

With the unit stabilised, long-term operational risk has been significantly reduced, supporting continued asset reliability and performance.

This project highlights the importance of specialist engineering capability in diagnosing and resolving complex mechanical issues within operational hydropower assets.

Accurate root-cause analysis, combined with precise execution in live operating environments, is critical to restoring performance and safeguarding generation.