Balancing needs and measures in the future West Central European power system with large shares of wind and solar resources Ingeborg Graabak Magnus Korpås Department of Electric Power Engineering NTNU, Norwegian University of Science and Technology Trondheim, Norway ingeborg.graabak@ntnu.no Michael Belsnes SINTEF Energy Research Trondheim Norway Abstract—The future European power system will include large shares of variable wind and solar resources. This paper analyses the variability for the eHighway2050 scenarios (from the EU 7 th Framework project) by modelling wind and solar resources from the COSMO-EU model. It quantifies the variability for the countries in West Central Europe, separate for each country, and integrated assuming there is no transmission limitations. The analysis results show that integration of systems by grids will have a smoothing effect on the variability. However, main challenges with periodically very low output will remain. The paper quantifies need for balancing taking present and future load profiles into consideration. The paper shows that many aggregated small-scale batteries only will have a limited effect on the need for balancing beyond a few hours. Finally, the paper discusses how the large reservoirs in the Norwegian hydropower system may serve to the balancing needs. Index Terms—Energy storage, power system planning, solar energy, wind energy. BACKGROUND The EU has stipulated a long-term goal to reduce greenhouse gas (GHG) emissions by 80%–95% compared to 1990 levels by 2050 [1]. The future power system in Europe will include large shares of wind and solar resources. Power production from wind and solar plants vary due to the variable resources. Since production has to meet demand all the time, measures are necessary in order to balance the production. In the present power system, dispatchable power plants balance the net load (the load minus the wind and solar power production). Reduction of conventional capacities based on fossil fuels is likely due to long periods with low power prices and because of the need to reduce GHG emissions. Other measures will be necessary to balance the variability in the renewable based power production. EU plans to expand interconnectors and to promote demand response for future balancing purposes [2], [3]. In Northern Europe, the flexible hydropower system in Scandinavia is an opportunity for balancing variable production [4]. METHOD This paper analyses the balancing needs for the future production from wind and solar resources in West Central Europe (see Table 1). It quantifies the need for balancing for scenarios from the EU 7 th Framework project e-Highway2050 [5]. The e-Highway scenarios are consistent with EUs targets for reduction of GHG emissions, and provide assumptions for development of wind and PV (photovoltaic) capacities for 106 clusters (regions) in Europe. E.g., there are assumptions for 7 cluster in Germany,15 in France etc. This study uses three of the eHighway scenarios: X5 (large scale Renewable Energy Sources (RES) including high amounts of offshore wind power), X7 (100% RES both large and small scale, including bio, hydro etc) and X16 (small scale RES with high amounts of PV power). In addition, we have developed a new scenario, called MaxRES. The eHighway project quantified maximum potential for wind and solar power production for the 106 clusters. The MaxRES scenario uses these maximum potentials. This paper uses wind and solar resources from the COSMO EU model. That model provides hourly wind and solar resources for the years 2011 – 2015 with a spatial resolution of 7 km x 7 km for the whole Europe [6]. Reference [7] describes the COSMO model, calculation of wind and PV power production and validation of the calculations by comparison with real production data from Transmission System Operators. Based on the same methodology as described in [7], this paper calculates wind power and PV power productions hour by hour by using COMSO weather data and capacities from the eHighway project. The hourly resulting time series with high spatial resolution are aggregated to national level. Wind and PV power production are added together to one combined hourly time series with variable RES production. This paper uses yearly demand for 2050 from the eHighway project and the present load profile (from ENTSO- E [8] ) as a starting point, but consider adjustment of the load