The growing global demand for electricity has led to a significant increase in power generation, with renewable energy playing a critical role in meeting this demand. However, conventional power grids, originally designed for traditional power generation, are becoming increasingly unstable when integrating renewable sources such as wind and solar energy. This case study delves into the innovative role of Battery Energy Storage Systems (BESS) in stabilising and supporting modern grids, with a particular focus on a large-scale BESS project undertaken by Tata Consulting Engineers (TCE).

The Need for Grid-Connected BESS

Integrating renewable energy into the grid presents challenges of stability and reliability. Renewable energy is inherently variable, and without proper storage solutions, grid operators struggle to maintain a consistent power supply. However, BESS offers a promising and hopeful solution. By storing energy when generation is high (such as during sunny or windy periods) and releasing it when demand exceeds generation or renewable energy sources are not available, BESS has the potential to revolutionise and transform the energy sector.

BESS has emerged as the preferred technology for grid storage due to its declining capital expenditure (CAPEX) costs, minimal space requirements, and flexibility in installation across a variety of terrains. It is a critical technology that not only maximises renewable energy usage and lowers energy costs but also significantly reduces our reliance on conventional power generation, inspiring a more sustainable energy future.

Challenges of BESS

Despite its advantages, BESS faces challenges that must be addressed for broader adoption. These include market volatility, the relatively short lifespan of the batteries, safety risks such as thermal runaway, and limited options for recycling. However, despite these obstacles, BESS continues to be a key player in the energy transition, highlighting the importance of our collective commitment to a more sustainable energy future.

Key Components of BESS

A BESS comprises three major systems: the battery system, the power conversion system (PCS), and the energy management system (EMS).

Additionally, the BESS includes other essential components like coupling transformers, medium-voltage switchgear, AC and DC panels, battery connection panels, low-voltage distribution boards, and auxiliary transformers.

Functions of BESS in Grid Operations

A BESS serves various functions that enhance grid stability and flexibility, including:

Case Study: Large-Scale BESS Project

Tata Consulting Engineers was involved in the basic engineering of a 100 MW/600 MWh BESS project designed for energy arbitrage. In this project, the BESS was integrated into a solar and wind hybrid power generation system, allowing the buying entity to receive consistent, round-the-clock power by supplementing intermittent renewable generation.

Project Specifications

The BESS was designed to operate efficiently within these parameters. The major equipment used in the project included 372.7 kWh battery racks, 3,500 kW PCS units, and 7 MVA inverter transformers.

Installation Details

To achieve the desired output at the POC, the project included the installation of:

The total round-trip efficiency (RTE) of the BESS system, excluding auxiliary power consumption, was calculated at 90.5%. The entire system was spread over a 6-acre site, reflecting the spatial efficiency of BESS technology.

Conclusion

This large-scale BESS system plays a vital role in supporting the grid by providing energy on an "on-demand" basis, especially during peak and off-peak periods. By charging when renewable power is available and discharging when it is not, the BESS contributes to a more stable and reliable grid. Additionally, it offers ancillary services that enhance grid resilience, making it an indispensable tool in the modern energy landscape.

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