Thermo-Economic Optimization of a Tower-Trough Combination Thermal Solar Power Plant

Current energetic context involving skyrocketing oil prices, population growing rates without precedents and increasing concerns about nuclear energy and climate change issues requires rapid, economically feasible and reliable progress in the field of renewable energies. We have the responsibility today of building the energetic scheme of tomorrow. Amongst renewable energies, thermal solar energy has already proven both reliable and competitive with adequate feed-in tariffs and offers some key advantages such as the possibility to store the energy as well as the good controllability of the transformed energy that translates into a great connectivity to the grid. The goal of this project is to perform a thermo-economic analysis and optimization of a solar thermal power plant combining two existing technologies, namely a tower and a parabolic trough power plant. To do so, accurate and reliable modelling of both power plants has been necessary. For the energyintegration, software developed at LENI (EPFL) has been used such as Osmose or Energy Technologies [2]. For the multi-objective optimization MOO [3] software, a LENI tool as well, has been used. Trough–tower combination power plants, when properly integrated, present higher energy efficiencies than those of either the tower or the trough power plants individually. Large power plants (around 80 MW) can be thus imagined (as large as current trough power plants) yet featuring an energy efficiency (17%) even higher than current state-of-the art tower power plants and similar levelised energy costs (0.08 USD/kWh) to typical values of trough power plants. These results represent another step forward for concentrating solar power, technology that is certainly called to play a major role in tomorrow’s energetic scheme.