Economic Evaluation of Turbining Potential in Drinking Water Supply Networks

The strategy document « Vision Energetique de la Suisse en 2050 », established by the Center for Energy Policy and Economics of Swiss Federal Institute of Technology (ETHZ), reveals the first impacts of climate change and underlines the fact, that the increasing energy consumption will influence the climate irreversibly in next few years and generate tremendous social, ecological and economic impacts. The only way to guarantee simultaneously the security of local energy supply as well as to protect the environment is the development and use of sustainable power supply systems. From this point of view, a sustainable energy production by small and micro hydropower plants becomes important. By its energetic potential, its low construction costs and its common availability in mountainous regions, drinking water turbining is especially attractive. For promoting this source of renewable energy, a computer tool was developed, evaluating the economic potential of existing supply networks. The TURBEAU software, developed at Ecole Polytechnique Federale de Lausanne (EPFL) in the framework of a project supported by the hydropower and energy department of Valais canton in Switzerland, is based on a simple and quick approach, allowing the definition of the economic turbining potential in drinking water networks with a minimum of input data. The numerical tool evaluates different locations for the turbine and its supply. The result should motivate the construction of economically interesting small hydropower plants, and therefore increase the production of renewable energy.A wide range of elements provides the system modelling by the user, taking into account the topological and geometrical characteristics of the network as well as the supply and consumption conditions. Cost indications are available for a preliminary economic analysis. The total evaluation cycle includes five steps: Calculation of the hydraulic profile of the network, definition of the energetic potential, financial analysis of configuration alternatives, economic life cycle analysis and comparison of optimised solutions.