India’s First Utility-Scale and South Asia’s Largest Standalone BESS at Distribution Level – A landmark in Urban Energy Storage

~82 GW solar and ~45 GW wind) by mid-2024 and a target of 500 GW by 2030. Peak demand reached ~250 GW in 2024, with cities like Delhi seeing fast load growth. This transition increases the need for flexible resources such as utility-scale BESS to provide frequency response, reserves, and local reliability, though practical experience at distribution level and in ancillary markets remains limited in India.

This paper presents the design, deployment, and operation of a 20 MW / 40 MWh LFP-based standalone BESS at the 33/11 kV Kilokari substation in South Delhi by BSES Rajdhani

Power Limited. The system operates at about two cycles per day, is housed in 12 liquidcooled containers maintaining ~24–25 °C, and is integrated at 11 kV within a dense distribution urban network. As of April 2026, the Kilokari BESS is India’s largest regulatorapproved project and the first distribution-level asset to participate in SRAS (Secondary

Reserve Ancillary Services), with Automatic Generation Control (AGC) as one of its key use cases. Tests show an end-to-end response delay of 8–20 s (≈3 s from the PCS), with the remainder from communication and metering. The plant closely tracks AGC set-points while respecting SOC and ramp limits, and we summarize its control architecture, testing approach, and performance metrics.

The paper reviews the Central Electricity Regulatory Commission (CERC) Ancillary Services

Regulations, 2022. Current SRAS settlement treats down energy as a payback via deviation settlement, creating a disincentive for storage. We propose a storage-specific settlement approach and benchmark it against practices in power markets in US (CAISO, PJM &

ERCOT), and European markets. The Kilokari case shows distribution-level BESS can deliver SRAS alongside grid support, highlighting regulatory changes needed to unlock value stacking across arbitrage, ancillary services, and network deferral.