Hydropower is a cornerstone of the energy transition because it provides reliable electricity at both small and large scales while helping compensate for the intermittency of renewable sources such as wind and solar. The energy transition, however, is also challenging engineers to develop hydropower projects under increasingly diverse operating and environmental conditions. Regions that were previously considered unsuitable for hydropower are now being considered for new applications.

A representative example is the pumped-storage hydropower system in Hatta, Dubai, interconnecting lower and upper reservoirs to generate electricity during periods of peak demand and pump water uphill during off-peak periods. Several countries have invested in small hydropower plants (<25 MW), including China, India, Brazil, and Uzbekistan, particularly to provide electricity to rural areas and support agricultural activities. In the United States and the European Union, significant investments have also been directed toward modernizing aging water infrastructure and supporting small-scale hydropower to strengthen the grid and increase renewable-energy utilization.

These developments expose hydro-turbine components to increasingly demanding and variable service conditions. Water quality and the operating regime may expose turbines simultaneously to hard-particle impacts, cyclic loading, and fluctuations in hydraulic pressure, leading to corrosion, erosion, abrasion, cavitation, and fatigue cracking.

Consequently, hydro-turbines experience material loss, reduced hydraulic efficiency, and, in severe cases, catastrophic failure. Cavitation and vibration-related damage can become particularly severe during transient operating conditions, especially during turbine start-up and shutdown. This is particularly relevant to hydropower plants developed to support the energy transition, where turbines may operate for only a few hours per day and consequently experience a greater number of start-stop cycles, increasing their exposure to damaging transient conditions and creating a stronger demand for more damage-resistant materials, surface treatments, and component designs. 

This article is part of our Frontiers in Power publication. Download to get the full issue.

This article covers:

• Cavitation risks in the era of frequent start-stop cycles
• Conventional engineering solutions for cavitation and vibration-related damages
• Recent field successes of legacy surface treatments and coatings
• Emerging solutions in experimental phase and their challenges
• Cavitation resistance of mature vs experimental materials