Analysis of the flexibility of Uzbekistan’s power system under increasing shares of variable renewable energy generation

Abstract

Relevance: In the context of the global energy transition aimed at reducing carbon intensity and increasing the sustainability of energy systems, the integration of renewable energy sources (RES) into national energy balances is gaining particular importance. The Republic of Uzbekistan, possessing significant solar and wind energy potential, is actively implementing a strategy for transitioning to “green” energy. According to the target indicators [15] approved by the Senate of the Republic of Uzbekistan, by 2030 it is planned to reach 27 GW of installed renewable energy capacity, which represents up to 54% of the total power system capacity of the country. The achievement of these goals will make it possible to save about 25 billion m³ of natural gas annually and reduce CO₂ emissions by 34 million tons, which is of strategic importance for ensuring energy security and fulfilling the country's international climate commitments. However, the increasing share of variable generation from solar (PV) and wind (WPP) power plants, combined with changes in power demand, necessitates a comprehensive analysis of operating conditions and system flexibility to ensure stable functioning of the power grid. The variability of renewable energy generation and electricity demand, as well as their dependence on weather conditions, require a high degree of flexibility and the ability to promptly manage the power balance. At the same time, a significant portion of Uzbekistan’s generating capacity is represented by gas-fired thermal power plants, including combined-cycle gas turbine (CCGT) units, highly flexible gas-piston units, as well as battery energy storage systems and hydropower plants, which allows assessing the system’s adaptability to RES and demand fluctuations. Thus, the analysis of system flexibility and the development of recommendations for improving operational control under the conditions of increasing variable renewable energy generation and demand becomes a highly relevant task, essential for ensuring the reliability, resilience, and efficiency of the power system.

Aim: To perform a comparative analysis of the flexibility assessment results with the actual operating conditions of the power system.

Methods: There were used a research method was applied that includes statistical time-series analysis to assess the variability of PV and wind power generation as well as demand dynamics. statistical methods of analysis and forecasting.

Results: As a result of the distribution of power among different types of sources involved in covering the required regulation range, the following shares were obtained: gas-piston power plants (GPPP): ≈40,5%; hydropower plants (HPP) ≈17,3%; Battery energy storage systems (BESS) ≈17,3%; Thermal power plants + combined-cycle gas turbines (TPP + CCGT, spinning reserve) ≈24,9%.