# Utilizing Energy Storage for Operational Adequacy of Wind-Integrated Bulk Power Systems
###### Abstract  
Renewable energy resources like wind generation are being rapidly integrated into modern power systems. Energy storage systems (ESS) are being viewed as a game-changer for renewable integration due to their ability to absorb the variability and uncertainty arising from the wind generation. While abundant literature is available on system adequacy and operational reliability evaluation, operational adequacy studies considering wind and energy storage have received very little attention, despite their elevated significance. This work presents a novel framework that integrates wind power and energy storage models to a bulk power system model to sequentially evaluate the operational adequacy in the operational mission time. The analytical models are developed using a dynamic system state probability evaluation approach by incorporating a system state probability estimation technique, wind power probability distribution, state enumeration, state transition matrix, and time series analysis in order to quantify the operational adequacy of a bulk power system integrated with wind power and ESS. The loss of load probability (LOLP) is used as the operational adequacy index to quantify the spatio-temporal variation in risk resulting from the generation and load variations, their distribution on the network structure, and the operational strategies of the integrated ESS. The proposed framework is aimed to serve as a guideline for operational planning, thereby simplifying the decision-making process for system operators while considering resources like wind and energy storage facilities. The methodology is applied to a test system to quantify the reliability and economic benefits accrued from different operational strategies of energy storage in response to wind generation and other operational objectives in different system scenarios. operational adequacy; wind generation; energy storage systems; bulk power systems; unit commitment +
Footnote †: journal: Applied  
operation. In modern systems, the operational planning task has become increasingly challenging as operators are required to utilize growing wind power while maintaining acceptable reliability at affordable costs. The assessment of operational adequacy, therefore, becomes increasingly important for modern and future power systems [5]. A significant amount of work is reported in long-term adequacy evaluation of power systems. Past works, such as References [6,7], present models and methods to quantify the contribution of renewables and ESS to system adequacy. These studies assist long-term investment decisions on generation as well as transmission facilities with renewable resources and ESS. Similarly, studies focused on the reliability of system operation are also noticeable. Reference [8] incorporates wind power into the unit commitment risk evaluation framework by extending the area risk approach, and Reference [9] extends it to include ESS into the unit commitment process to assess the reliability benefits. The utilization of a flywheel energy storage system to lower a power system's recovery risk is presented in Reference [10]. Operational adequacy studies, on the other hand, lag considerably behind adequacy studies for long-term resource planning and operational reliability studies for real-time system studies. References [11,12] present operational adequacy studies considering wind, photovoltaic, and ESS, focusing on the ramping needs of conventional generation. The consideration of renewables and ESS in operational planning is still evolving in power systems, and policies regarding their participation in electricity markets seem to vary among jurisdictions [13,14]. In this regard, Reference [15] presents an operational reliability study of ESS application as a potential reserve using a modified Pennsylvania New Jersey Maryland (PJM) approach.