Regional disparity of flexibility options for integrating variable renewable energy

Integrating massive variable renewable energy requires sufficient flexibility to maintain stability of power systems. Incorporating flexibility options could provide insights into the system operation optimization for fully integrating wind and solar power. In order to find regional disparity in flexibility options under various system configurations and power demands, we quantify the flexibility requirement by residual load curve and formulate the flexibility provision by an integrated optimization model to present flexibility solutions and distributions in power system operations. The model integrates the interactions of demand side response, energy storage and interregional interconnection. A case study of China is conducted. The results indicate that demand flexibility enables cost-efficient integration of variable renewables in coal-based and load-centred areas. Regions with abundant renewables prefer to adopt the integration option of demand side response and energy storage to meet the dramatically fluctuating flexibility requirement. Interregional transmission provides a necessary solution for areas with imbalanced power supply capability and electricity demand.