The Solar Energy Corporation of India Limited (SECI) commissioned India's largest Battery Energy Storage System (BESS) in 2024 at Chhattisgarh. This is a major development in the field of renewable energy storage, helping in enhancing the state’s energy infrastructure and promoting green energy technologies. The project aims to ensure the stability of the electrical grid and support renewable energy generation.
Thus, the correct answer is Chhattisgarh.