Enabling renewable resource integration: The balance between robustness and flexibility

The steady rise of electricity demand and renewable energy sources is increasing the need for flexibility to enable power systems to adapt to changes in supply and demand. To this end, demand response programs have the potential to increase the flexibility of the system. In this work, a direct-load-control demand response program is used in the scheduling task of a power system with high levels of variable renewable generation. The model considers different classes of reserves provided by both conventional generation and responsive demand. Unit commitment, generator dispatch and reserve allocations are determined with appropriate risk-averse levels to guarantee a reliable and feasible operation of the system across the planning horizon. Risk preferences are reflected in constraint satisfaction via robust and probabilistically-constrained approaches. Case studies with a 57-bus system show that the probabilistic approach allows higher wind share in the power network and incurs lower costs than the robust approach. In addition, results show that controllable loads are an important contributor to system flexibility, though addition of other classes of responsive demand will also bring desirable flexibility.