Regulated penalties exist for different degrees of deviation. Throughout the intraday market, REE opens six consecutive clearing auctions that allow adjustments of power plants and optimisation of the system based on real-time information and updated forecasts. This solution, along with the introduction of a dedicated renewable energies integration management centre (CECRE), a pioneering initiative to monitor and control renewable energy resources with the objective to integrate the maximum amount of production from variable renewable energy sources under secure conditions has allowed an efficient introduction of wind power in Spain (REE, 2010). The TSO has maintained constant the required balancing capacities, despite the enormous penetration of wind power in Spain and the fact that the Iberian peninsula has limited interconnections with neighbouring countries.