Integration of Battery Energy Storage Systems into Natural Gas Combined Cycle Power Plants in Fuzzy Environment

•Integration of BESSs into NGCCPPs was evaluated for the first time by fuzzy-MCDM.•Operational flexibility was examined using both grid actors and rational methods.•The effect of BESS selection under different conditions has been calculated.•BESSs have promising results that can provide economic returns to NGCCPPs.•Pythagorean fuzzy sets were used for the first time for technology integration. The increasing share of renewable energy sources in the grid has created the need for operational flexibility for natural gas combined cycle power plants (NGCCPPs) that offer high thermal efficiency and ease of operation. However, battery energy storage technologies (BESSs), which eliminate the time and ratio imbalance between energy supply and demand, will be effective solutions that can increase plant flexibility when integrated with NGCCPPs. This integration is a decision problem with high uncertainty and complexity evaluated by grid stakeholders. For this reason, firstly, the operational goals of the power plants have been prioritized in terms of BESSs. At this phase, the combination of Pythagorean Fuzzy AHP and Pythagorean Fuzzy TOPSIS methods was used. Afterwards, to pose a sustainable projection under the mentioned operational goals, which is the main purpose of the study has been started to the phase of ranking BESSs (lead-acid, lithium-ion, vanadium redox flow battery, sodium-nickel chloride, sodium-sulfur) under different conditions. By this means, evaluating the BESSs for different application purposes, rationalizing the high uncertainty in both the energy sector and electricity markets at the same time with the proposed hierarchical model will provide an important projection to the literature. The results of the proposed methodology show that lithium-ion batteries can be an effective replacement technology alternative for NGCCPPs, given their economic benefits and technological capabilities. Another result is that the scalability of BESSs can be used for different operational goals in the power plants. This also can allow the establishment of a hybrid BESS facility.