Assessing complementarity of wind and solar resources for energy production in Italy. A Monte Carlo approach

Wind and solar energy are expected to play a major role in the current decade to help Europe reaching the renewable energy penetration targets fixed by Directive 2009/28/EC. Nevertheless, both wind and solar energy actual production profiles are difficult to be predicted and depend heavily on the meteorological features of sun radiation and wind speed. In ideal system where wind and solar electricity are both injected in a fast reacting grid instantaneously matching supply and demand, wind and solar electricity production profiles should complement each other as much as possible in order to minimize need for storage and additional capacity. In the present paper the complementarity of wind and solar resources is assessed for a test year in Italy. To achieve this goal, high space and time resolution data for both sun radiation and wind speed in Italy obtained from running two state of the art models (PVGIS and MINNI) are employed: hourly profiles for solar and wind energy produced in each 4x4 grid point in Italy in 2005 are compared and hourly, daily and monthly correlation coefficients are computed in order to locally assess the complementarity of the two resources. Moreover, a Monte Carlo approach is also developed in order to assess how large scale wind and solar energy productions are expected to complement each other when up to 100 relevant production sites will be built spread all over Italy or its major geographical areas (North, Centre, South, Sardinia and Sicily). The results show how local complementarity can be very interesting with monthly correlation coefficients reaching values lower than -0.8 in several areas. Large-scale complementarity is also relevant with nation-wide monthly correlation coefficients showing values between -0.65 and -0.6 . These results provide the indication that in the sample here of 2005, wind and solar energy potential production have shown behaviours complementary in time, favourably supporting their proper integration in the energy system.JRC.F.7-Renewable Energ