The 2030 Framework for climate and energy sets as EU-wide targets for 2030 a 40% cut in greenhouse gas emissions compared to 1990 level, and at least a 27% share of renewable energy consumption. For the power system, this means a share of at least 45% of electricity demand generated from renewable sources (European Commission), compared to 27.5% in 2014 (Eurostat). A significant part of this additional renewable energy will come from variable energy, produced by wind and solar technologies, which bring new challenges in terms of security of supply and electricity price volatility.
Indeed, the variable nature of renewable energy generation driven by weather conditions induces high fluctuations of residual demand1 and consequent needs for thermal generation: important capacity back-up is required to face periods of low Renewable Energy Sources (RES) generation while the high fluctuations in the use of these thermal units imply additional fuel and start-up costs. In this context, interconnectors, demand response and energy storage can play an important role in increasing system flexibility and smoothing residual demand. As presented in Table 1, a portfolio of flexibility solutions with complementary time characteristics will be necessary to efficiently integrate high shares of variable energy.