A study to investigate the impact of different sized small scale hydropower systems on river characteristics

Abstract

The UK currently derives less than 2% of its total energy from renewables, 27% of which is sourced from hydroelectric power. As part of the EU Commission’s 20 20 package, the UK agreed that by 2020 15% of the UK’s energy would come from renewable sources. Hydroelectric power is a viable renewable energy source from which to meet this target, making further research in the field essential. Though large hydro systems are currently the main source of hydroelectric energy for the UK, the potential for small hydropower far exceeds the amount currently in place. The environmental impacts of small hydropower have not been thoroughly researched, and studies which have been undertaken often contain contrasting results. This dissertation looks at the impacts that small, run-of-river hydropower systems have on river characteristics. Five case studies were chosen, all with similar turbines but with different energy outputs. Several parameters were looked at including the river velocity, discharge, temperature, pH, dissolved oxygen, electrical conductivity, suspended sediment, and macroinvertebrate populations. The results found upstream of the turbine were compared to the results from various distances downstream of the turbine. The research found that changes in several parameters were present in each of the rivers as a result of the hydro turbine installation. The results were turned into percentage changes so that comparisons could be made across all five rivers. Though some parameters indicated that more severe impacts were found in the larger rivers, such as temperature, pH and dissolved oxygen, other changes which were found appeared to be more dependent on the river’s geometry and the time of year during which the study was undertaken.