Building a resilient grid with Battery Energy Storage System

Electricity grids need inertia to prevent blackouts, but renewable energy like wind and solar lacks it.

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Grid-forming inverters, synchronous condensers, and battery energy storage systems are needed to tackle this. The uncertainty of variable renewable energy (VRE) and rapidly changing load patterns call for RE integration to be supplemented by flexibility in generation resources, grid capacity, peak load shifting, and demand balancing to ensure supply security, quality of supply, and grid stability. A reputed power distribution company (DISCOM) in India, facing a similar dilemma, embarked upon an ambitious pilot project to resolve this.

Solution implemented

The DISCOM conducted a detailed load flow study to identify vulnerable sections of the power distribution network and evaluate their ability to respond to grid contingencies, such as load spikes, voltage/frequency fluctuations, and harmonic disturbances, during VRE connections. Based on the study, the DISCOM decided to install a utility-scale Battery Energy Storage System (BESS) with a 10 MWh capacity at one of its distribution substations, to operate in coordination with VRE sources to achieve peak load management, voltage control, and grid stability. The pilot, financed by ADB to the tune of INR 150 crores ($18.2M), is South Asia's first distribution level, grid scale BESS project, intended to validate technical performance, operational procedures, and commercial use cases, with future scalability of an additional 50 MWh based on the pilot's learnings.

Strategies adopted

The following key strategies were adopted:

Charging/Discharging: Charge the batteries during energy surplus hours and discharge to the grid during energy-deficient hours to manage load and provide grid support.

Volt/VAR management: Coordinate BESS capacity with VRE generation to maintain voltage profiles and reactive power, in accordance with regulatory standards.