Optimal combination of energy storages for prospective power supply systems based on Renewable Energy Sources

摘要

Prospective power supply systems based on Renewable Energy Sources requiremeasures to balance power generation and load at all times. The utilisation ofstorage devices and backup power plants is widely suggested for this purpose,whereas the best combination is still to be found. In this work, we present amodelling approach to systematically study scenarios of future power supplysystems with a high share of electricity originating from wind and solarresources. By considering backup as a subordinate source of electricity withenergy-only costs, the approach is independent of the actual full-load hours ofthe backup power plants. Applying the approach to multi-year meteorologicaldata for Germany, cost-optimised combinations of storage devices and backuppower are identified. We find that even in scenarios with significant excessgeneration capacities there is a need for storage devices or backup powerplants with discharging power on the same order as the average load to balancethe system at all times. Furthermore, these capacities seem to be required insome years of the multi-year period only. Our results imply that the societalneed of having electricity available at all times can likely be satisfied byinstalling over-capacities only, whereas a balance has to be found betweeninstalling additional backup or storage or generation capacities.