Hydropower operators face the challenge of modernizing aging plants while meeting ever-increasing demands for efficiency, reliability and sustainability. Revitalization requires not only technical expertise, but also the ability to integrate new solutions into existing structures. This was precisely the challenge faced in our latest European project: To transform an aging plant into a state-of-the-art, high-performance facility. Instead of a simple refurbishment, the customer opted for a completely new traction chain, including wicket gate and turbine shaft, combined with individually tailored guide vanes. Achieving this integration within the constraints of the existing structure required not only advanced engineering expertise but also innovative manufacturing and on-site machining techniques such as precision line boring. By uniting these methods, Global Hydro ensured perfect alignment between new and existing components, enabling optimal hydraulic performance, improved efficiency and long-term operational stability.
The project began with a bold objective: Upgrade an aging hydropower plant, originally commissioned in the 1960s, to a modern facility capable of high efficiency and reliability for decades to come. Instead of a partial overhaul, our customer requested a completely new traction chain, including wicket gate and turbine shaft - a departure from typical revitalizations where components are often only refurbished.
In addition, the goal was to upgrade the existing machine - enabling faster start and stop sequences and quicker response to load changes. This capability is increasingly essential for power grids with a high share of wind and solar generation, where flexibility and reaction speed are key to maintaining stability. Along with these improvements, hydraulic optimizations increased the turbine’s efficiency by around 3% at nominal discharge, resulting in higher power output and improved overall performance. Together, these measures transformed the unit into a modern, high-performance system ready to meet the demands of today’s dynamic energy landscape.
Achieving the ultra-tight tolerances required for this revitalization began long before installation. With few original drawings available, a Global Hydro specialist was on site to carry out extensive 3D measurements and photo documentation, capturing all critical dimensions of the existing structure. Using a Laser Tracker with sub-0.01 mm accuracy and more than 500 measuring points, all critical dimensions of the existing structure were captured and temperature-compensated in a central coordinate system. This data made it possible to position the newly manufactured wicket gate ring precisely relative to the existing lower ring, to machine the guide vane bores on site with pinpoint accuracy, and to adjust the length of each individual guide vane for a perfect fit. Even the discharge ring was measured to enable the new runner to be machined for optimal clearances.
A defining feature of this revitalization project is the advanced on-site line boring process carried out directly in the powerhouse. Since the original turbine design has the lower wicket gate ring permanently embedded in concrete, removal or replacement was not an option. Therefore, a mobile machining center was installed directly on the new upper wicket gate ring. From this precisely aligned reference point, the lower guide vane bushings were bored with sub-millimeter accuracy. This method allowed the new guide vanes to be matched perfectly to the existing lower wicket gate ring and ensured that every bearing bore sat exactly in the designed position. Achieving this level of alignment was essential to maintain an exceptionally small guide vane clearance and ensure smooth operation.
By performing the machining on site, Global Hydro avoided time-consuming civil works and achieved a seamless fit between new and existing components. This approach reflects Global Hydro’s commitment to precision, adaptability and continuous innovation in hydropower modernization.
The revitalization demanded more than precision machining. Several unique conditions required custom-engineered approaches, each highlighting Global Hydro’s ability to adapt designs and methods to even the most challenging environments.
Before transport to site, the traction chain was pre-assembled to the highest possible degree at our Austrian Innovation and Manufacturing Center. This extensive preparation ensured that all interfaces and tolerances were validated under workshop conditions, reducing complexity and risk during installation on site.
A separate in-house factory acceptance test allowed the customer to witness pressure tests and assembly quality first-hand. Their satisfaction during the FAT confirmed that the assembled components fully met the stringent quality and testing standards set by Global Hydro.
Given the scale of the components - the traction chain alone measuring 6.7 x 3.0 x 3.3 m - transport had to be carefully planned. All parts were shipped via truck and ferry, with the traction chain requiring special handling due to its size. Nevertheless, delivery to site took just approximately one week, keeping the overall project timeline on track.
Revitalizing a decades-old hydropower plant required an exceptional level of precision from the very start. With only limited documentation available and extremely tight tolerances to meet, every detail had to be carefully planned and executed.
Global Hydro responded with a fully integrated approach. Every interface was surveyed, components were designed and pre-assembled to the highest tolerances at our Innovation and Manufacturing Center in Austria, and advanced on-site line boring aligned new and existing parts directly in the powerhouse.
The result is a revitalized plant that delivers higher efficiency, greater operational flexibility and extended service life. By uniting engineering, manufacturing and installation into one coordinated process, Global Hydro ensures that even the most challenging sites become high-performing, future-proof renewable energy assets.
Every project has its own challenges and goals. Contact our experts to discuss your requirements - Global Hydro develops tailored revitalization solutions to meet your specific needs.
Roland Fleischmann
Senior Sales Manager Revitalization
+43 (7285) 514 0055
roland.fleischmann@global-hydro.eu Contact
