PV ARRAY PERFORMANCE IN A HYBRID POWER PLANT AND SHADOW EVOLUTION ASSESSMENT

A hybrid power plant consists of an onshore wind farm with photovoltaic plants installed in the same location, along with storage systems able to maintain power and voltage output stable. Since aerogenerators need to be at enough distances from each other to avoid perturbations and turbulence that can decrease overall electricity production and efficiency, a wind park occupies a huge amount of land. To optimize terrain utilization, soil under turbines can be employed for agriculture, for producing more energy with PV plants or both with agriphotovoltaics. With PV plants for example the investments required for grid connection can be reduced while bureaucracy is less a burden, allowing to reach a lower LCOE and making produced electricity more competitive compared to conventional sources. All these advantages have driven a lot of interest towards hybrid power plants, with many private enterprises jumping into this new market. The wind farm that is considered in this thesis is composed of five aerogenerators located at Gravina in Puglia (Bari province, Italy). STE ENERGY S.R.L., an engineering company in Padua, is planning to design a large-scale PV plant at this wind park position, making hybrid power plants a reality also in Italy. The goal of this master’s degree thesis is the assessment of wind turbine tower, nacelle, rotor and blades shadows influence on a possible PV plant’s annual energy production, trying to understand the effect that losses related to shadings have on its total yield. This target is achieved by two software exploitation: PVSYST and windPRO. Their results are then merged, reaching higher accuracy on shading influence assessment on PV plant performance. Furthermore, wind turbine shadow evolutions over a single day and during smaller periods are mathematically modelled inside MATLAB software, to analyse its behaviour, to evaluate the dimensions of area affected by shadow and to see which instants of time a single module or a simple PV array is shaded. Moreover, the blade shadow flickering phenomenon, that is essential for every environmental impact analysis, will be evaluated to obtain approximated values of number of hours and days in a year when shadow is present around aerogenerators. In conclusion the dynamic effect that intermittent shading has on a small PV array performance (voltage, current, power output) with a MPPT algorithm will be described by SIMULINK and SIMSCAPE ELECTRICAL software models. All this work will prove the feasibility of PV plant existence together with aerogenerators, since shadow linked energy losses are not so high and the problem related to solar irradiance oscillation and then output fluctuations towards inverter can be solved with a MPPT algorithm and a control system. If designer’s wish is to completely avoid any shadow flickering problem, modules can be placed at distances higher than spatial trend of shadow casted by wind turbine during Winter solstice.