BESS Plant Setup – Part 1

The increasing number of Battery Energy Storage System (BESS) tenders in India is encouraging various companies to enter the domestic BESS manufacturing sector. Moreover, the decline in battery cell prices has made energy storage solutions more viable for commercial and industrial applications. Rahul Bollini, a BESS expert, is writing a series designed to guide emerging companies in BESS manufacturing.

Understanding Customer’s Requirement

There are many aspects of the market that a new BESS manufacturing company should understand, including the following:

• BESS manufacturing from module to cluster and then to a container – Imported battery packs are subject to an 11% (10% + 1%) duty, which may increase in the future to encourage domestic BESS manufacturing.

• BESS manufacturing from cell to module, module to cluster and then to a container – Imported cells attract a duty of 5.5% (5 + 0.5%) under the IGCR scheme for battery manufacturing.

• The savings in customs duty for making BESS from the cell level onwards help mitigate the competitively priced imports, which either come as a complete system or in semi-knockdown (SKD) condition.

• Local BESS companies are also expected to support BESS installation. Therefore, it is a good idea for BESS manufacturing companies to thoroughly understand the installation process and provide commissioning support, which a foreign company may not be able to offer.

• Always document the customer’s requirement in the questionnaire and provide a solution accordingly. In commercial and industrial (C&I) projects, regular misunderstandings occur.

The section below presents a simple questionnaire for C&I projects.

Basic Checklist for Understanding Customer’s Energy Storage Requirement

Points to Consider:

• In cases where solar PV is not yet installed, the hybrid inverter can be an option for managing both battery and solar PV. However, hybrid inverters are expensive, and they are not available in large power ratings. For large capacity power, AC coupling is preferred.

• If the battery system is to power the application along with the DG, the voltage, frequency, and phase angle must match those of the DG and the battery inverter.

• If a battery is used less frequently, its cost of storing unit energy will increase, which will threaten its viability. Batteries experience calendar ageing whether you use them or not. Hence, it is highly recommended to use the battery more and make it more economical to store unit energy, enabling the storage of off-peak energy.

• If a customer requests a 1 MWh battery solution, it may not necessarily mean that they require 1 MWh of battery capacity; it can also mean that they want 1 MWh of energy to be supplied to their loads. In this case, one needs to account for power conversion and transmission losses along with acceptable operating depth-of-discharge (DoD). Similarly, PCS oversizing is required to account for power conversion and transmission losses, and PCS derating is necessary when operating at higher altitudes or in higher temperatures.

• Since battery capacity degrades with ageing, it is also important to understand if the customer can accept this degradation in terms of lower backup hours on a yearly basis. If they cannot accept it, then battery oversizing must be done to accommodate the annual degradation for the years until the customer demands no change in power and backup requirement.

In part 2 of this series, I will write about understanding grid-connected projects and its detailed questionnaire. Stay tuned for the next issue.

About the author

Rahul Bollini is an R&D expert in Lithium-ion cells with 10 years of experience. He founded Bollini Energy to assist in deep understanding of the characteristics of Lithium-ion cells to EV, BESS, BMS and battery data analytics companies across the globe. Contact | +91-7204957389; bollinienergy@gmail.com.

This article was first published in the EVreporter June 2025 magazine.

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