The impact of climatic extreme events on the feasibility of fully renewable power systems: a case study for Sweden

Abstract

Future energy systems with high shares of intermittent renewables will be stressed by climatic extreme events. We assess the frequency, duration, and magnitude of such extreme residual load events with a share of VRE generation of about 50% for the case of Sweden. For our analysis, we use 29 years of river runoff and of wind power and PV generation simulated from physical models. Hourly load is simulated from temperature data with a time series model. The resulting time series are combined with historic capacity and ramping restrictions of hydro and thermal power plants in an optimization model to minimize extreme residual load events. Results indicate that under high VRE shares climatic extreme events affect even highly flexible power systems as the Swedish one. Replacing current nuclear power capacities by wind power results on average in three extreme residual load events per year. These events are partly linked to the observation that wind speeds are likely below seasonal average in very cold weather conditions. Deploying PV generation capacities instead of wind increases the number of extreme residual load events by about 6 %, as most events occur during the winter month when solar generation is close to zero.