spain has also developed transparent and accessible meteorological forecasts with cecre and its advanced forecast model sipreolico de la fuente a system that shares balancing responsibilities with producers will induce as well variable renewable producers to develop their own forecasting resources in order to minimise their deviations from the dayahead forecast ie internalisation of system integration costs due to unpredictability all parties have to share benefits and responsibilities from system balancing and there exist nowadays a variety of power market designs allowing increased internalisation of system costs several key features of such improved designs are presented in the following thus energy provision and balancing services can be planned in advance by power utilities the challenge appears within power systems with large amounts of variable renewables especially wind