Harnessing Flexibility from Energy Storage and Turndown Capability of Generating Units

Flexibility in operations is gaining importance to facilitate large share of renewable energy sources in generation mix. Various resources and market-based ramp products are practiced for enhancing system flexibility. This work aims at modelling such flexible ramp products from conventional units and Energy storage systems, especially pumped hydro energy storage and battery energy storage systems. The paper further presents a techno-economic analysis of two flexibility enhancement methodologies-Energy storage systems and lower technical minimum of generating units. A MILP based scheduling problem with a 15-minute temporal day-ahead security constrained unit commitment and a 5-minute temporal real-time security constrained economic dispatch is formulated with FRP procurement decisions in day-ahead scheduling for the studies. Effectiveness of proposed model is studied on IEEE RTS 24 bus system using GAMS 24.2.3. Results show that integration of ESS coupled with lower technical minimum of conventional units would enhance market efficiencies and system reliability.