PNNL

Abstract

Small-scale hydropower is an important component in meeting worldwide demands for renewable energy, with an estimated potential of an additional 18 GW of capacity in the United States and 23 GW in the European Union. Siphon turbines are an attractive type of small-scale hydropower turbines because they can be retrofitted into existing structures where there is already a drop in water elevation. A siphon turbine conveys water from an upper reservoir to a lower reservoir through the use of a siphon structure that goes over the top of the dam, as opposed to traditional turbines that require breaching the dam structure. A small, neutrally buoyant autonomous sensor package known as a Sensor Fish was deployed through a siphon turbine at the Head of the U Hydroelectric Project in Idaho, USA. The data collected by Sensor Fish can be used to understand the forces and motion that fish would experience during passage through a turbine. Comparisons were made between the siphon turbine in this study and other low-head turbines that have been studied using Sensor Fish. The Sensor Fish measurements indicate that this siphon turbine can generate nadir (i.e., minimum) pressures during runner passage of 22.4 kPaA, which are much lower than those of other turbine types that have been studied using Sensor Fish and could be potentially harmful to fish susceptible to barotrauma. For this reason, stakeholders should determine whether any fish species-of-concern in the area are susceptible to barotrauma, and if so, proper screening technology should be investigated or an alternative style of turbine should be considered.