BSES Rajdhani had proposed to set up 6 Li-ion based Battery Energy Storage Systems (BESS) connected to the LV side (415V) of distribution transformers across Delhi. The 6 sites chosen were in Vasant Kunj, Tughlakabad, Janakpuri B3, Janakpuri B6, Pratap market and Lajpat Nagar. The BESS were envisioned to be used for energy cost arbitrage during the winter months and for peak load shaving during the summer months. The total capacity to be installed was 510 kW / 1050 kWh.
The project was executed by AmpereHour Energy and Coslight (battery partner). Several challenges were faced during project execution due to the difficult, space constrained locations in which the BESS had to be set up as well as external challenges related to the Covid pandemic second wave. However, despite the hurdles, the project was successfully completed in the first week of December 2021, handed over and is in operation as of today.
This project features a central Energy management system, AHE’s ELINA-Server, set up in the BSES Rajdhani SCADA centre, which allows the customer to centrally control and monitor the behaviour of all 6 distributed BESS sites, creating the first of its kind Virtual Power Plant (VPP) in the country. The BESS can be set up in multiple modes of operation such as Energy shift, Peak shaving, manual mode etc. and the configuration for each of these modes can be set remotely.
Regular operation of the system is either 1 cycle per day or 2 cycles per day in energy shift mode subject to client requirements and energy pricing. In the first 8 months of 2022, the total energy discharged from the 6 BESS sites was 178 MWh, roughly equivalent of 265 cycles as per the committed capacity.
Overall system availability for all 6 sites was 96.1% over the course of the 8 months despite challenges associated with high temperatures during the Delhi summers as well as long grid outages leading to site downtime owing to UPS capacity limits. Maximum availability of 99.4% was achieved at the one of the sites.
In the month of June, the BESS were run in peak shaving mode. The system was set to discharge to shave peak loads above 70% of DT loading (~700 kVA) and charge below 50% of DT loading (~500 kVA).
The BESS was also utilized to successfully demonstrate power factor improvement by providing reactive power as required by the load, subject to the limitations of the PCS capacity.
The BESS was also utilized to successfully demonstrate phase balancing – reducing the current differential across the 3 phases – by providing unbalanced reactive power from the PCS
Over the course of 8 months the BESS was cycled successfully in ambient temperatures ranging from 16 C (in January) to 56 C (in May).