Evaluation of Various Flexibility Resources in Power Systems

Variable Renewable Energy Resources (VRES), especially wind and solar power, are known for their intermittent, uncertain, and low-energy-density nature. The increasing adoption of these stochastic sources presents irregularity in the net load in the power system network; therefore, it poses a challenge to the reliable operation of power systems. Consequently, there's an increasing need for power system flexibility to cope with VRES-related challenges. Flexibility planning will therefore be a crucial aspect for power system management, particularly as the penetration of VRES continues to rise. To reach this objective, the diversification of flexibility options emerges as a promising solution. Various strategies are prominent in the literature for enhancing power system flexibility to adapt to VRES variability. These include the utilization of flexible generators, adjusting load profiles through demand-side management, integrating energy storage systems and electric vehicle batteries, developing grid infrastructure, using surplus energy for various daily applications (e.g., heating), and the implementing of curtailment practices. Demand-side management and energy storage, for example, offer valuable flexibility by allowing consumers to adjust their consumption patterns to electricity supply and demand fluctuations. Additionally, flexible generation technologies like gas turbines and combined heat and power systems provide rapid responses, aiding grid balance during high VRES output variability periods. Overall, this paper provides an overview of power system flexibility, exploring the various flexibility resources available to VRES-related challenges. Finally, this paper emphasizes the importance of continued innovation in developing new flexibility solutions to meet the growing demand for sustainable and reliable power systems.