A study on the placement of turbines downstream of a hydroelectric power station

Sammanfattning: Human energy related activity has increased the carbon dioxide concentration in the atmosphere by 40 % since the preindustrial area. A leading contributor to this is the burning of fossil fuels in order to extract energy. Due to this, we are today facing many issues following climate change and global warming. The search for renewable energy sources is therefor of outmost importance. The biggest renewable energy source today is hydropower. It is big in newly industrialized countries such as China and Brazil, where in the latter it covers over 70% of the electricity supply. A relatively unexplored area is the implementation of turbines in the downstream of a hydroelectric power station. The risk here is that the turbine[s] will increase the water depth and hence impact the hydraulic head i.e. the potential power of the hydro power station negatively This report explores the potential and optimal placement of a turbine/ turbine fences in the downstream by using the Bernoulli equation. Two different cases are examined. The geometry in the first one is a finite uniform channel whereas in the second one it is a finite divergent channel. The equations for the two different cases will also vary, mainly in the expression of the friction loss. It is shown that the choices of expression for the friction loss and geometry are important for the results as the two cases gave different results. However, the second approach is supposed more accurate and shows that the closer the beginning of the channel the more power can be extracted but this also means an increase in water depth. For some flows and turbine diameters a turbine fence was also placed further on, hence departed from the expected result. This shows the complexity of the problem and the importance of an optimization model.