Hydropower plants (HPPs) contribute to energy supply from renewable resources. Turbines in HPPs transform the power of flowing water to rotary motion which drives electric generators. The water which flows through HPPs may contain suspended sediment (Pict. 1). Handling these sediments is a major challenge to HPP designers and operators.
Coarse sediment is excluded in gravel and sand traps at water intakes. Finer sediment particles, typically smaller than 0.3 mm, cannot be excluded completely, since the required facilities would be too expensive. These relatively fine particles can still cause significant abrasive erosion on turbine parts. This leads to high maintenance costs and production losses. A main reason for production loss is that the turbine efficiency is reduced if the turbine is eroded.
Most abrasion problems on hydraulic turbines are known from HPPs in the Himalayas, the South-American Andes and the European Alps.