Economic and environmental impact of photovoltaic and wind energy high penetration towards the achievement of the Italian 20-20-20 targets

The paper presents an analysis of the operating parameters of the Combined Cycle Gas Turbine (CCGT) systems in Italy in the years from 2006 to 2013, studying the environmental and economic impact of renewable energy sources spread on CCGT. Variable Renewable Energy (VRE) sources development, electricity demand reduction and CCGT overcapacity have affected the CCGT systems that have had to operate at partial load, experiencing several rump-up/down cycles in a day. The consequent increase of CO2 emission and costs have to be considered in a RES high penetration future scenario. The paper aims to evaluate the net avoided emissions by RES and the cost that Italy have incurred to avoid to emit a tonne of CO2. To reach the high penetration of RES targets the attention is switching from the problem of adding more renewable energy installations to the problem of managing the whole "green" electricity production in a smarter way. Considering all the indirect effects caused by RES on the electricity system is essential for everyone who wants to analyse future scenarios.