Reduced storage and balancing needs in a fully renewable European power system with excess wind and solar power generation

The storage and balancing needs of a simplified European power system , which is based on wind and solar power generation only, are derived from an extensive weather-driven modeling of hourly power mismatches between generation and load. The storage energy capacity , the annual balancing energy and the balancing power are found to depend significantly on the mixing ratio between wind and solar power generation . They decrease strongly with the overall excess generation. At 50% excess generation the required long-term storage energy capacity and annual balancing energy amount to 1% of the annual consumption. The required balancing power turns out to be 25% of the average hourly load. These numbers are in agreement with current hydro storage lakes in Scandinavia and the Alps, as well as with potential hydrogen storage in mostly North-German salt caverns .