According to the multiple pieces of evidence provided, the largest battery energy storage system (BESS) project in India is the 1000MWh project in Rajasthan awarded by Sterling & Wilson. The project is expected to be completed in 2025 and will be the largest BESS project in India.
In contrast, the other mentioned projects such as the project of Tata Power in cooperation with Sungrow and the independent energy storage tender launched by SECI are larger in scale, but their scale is less than 1000MWh.
Therefore, based on the above information, it can be determined that the largest BESS project in India is the 1000MWh project in Rajasthan awarded by Sterling & Wilson.