Battery energy storage system (BESS) for factories — peak shaving, fewer DG hours and backup
A battery energy storage system stores energy from your rooftop solar or the grid and releases it when your load peaks, when the grid drops or when the tariff is highest. For a factory that means up to three savings — a lower recorded maximum demand, fewer DG hours and evening units moved out of expensive slots. Whether any of them pays depends on your load curve, your tariff and the battery's warranty, so that is where we start.
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15+ years of industrial electrical work · HT/LT, DG & fire under one contract · ISO 9001:2015 Certified
Request a BESS sizing review
Four details to start. Choose “Solar with battery or backup” below — an engineer reviews your site and tells you what load data the sizing needs.
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Send my electricity bill on WhatsAppWhat the assessment covers — and what it does not
What an engineer looks at: a suitable system size range for your site; how much of your roof is realistically usable once shading, skylights and walkways are taken out; how much of your consumption falls in daylight hours, because that is what solar can actually offset; an indicative investment range; and the engineering checks that come next — sanctioned-load headroom, roof structure and the DISCOM route for your district.
Assumptions we state rather than hide: generation figures are modelled from regional averages, not measured at your site. Indicative costs are exclusive of GST and exclude roof strengthening, HT-side works, battery storage and statutory fees.
What this is not: not a detailed engineering design, not a guaranteed saving, not an assurance that any approval will be granted, and not a commitment to a site visit. Your connected load is not the same as the solar capacity you can install, and solar offsets energy charges — it does not make an entire bill disappear. Where a number depends on something we have not seen, we will say so rather than assume it.
What a battery energy storage system does for a factory's bill
Peak shaving
The battery discharges during your highest-demand intervals, flattening the peak the DISCOM bills you on. Industrial tariffs bill contract and recorded maximum demand separately from energy — a charge solar alone never touches.
Demand-penalty avoidance
Exceeding sanctioned or contract demand draws penal billing in most North Indian states. A battery that caps your recorded peak works as insurance against those months.
Fewer DG hours
Short outages and evening peaks that force a DG start today can ride through on stored energy. Diesel is the most expensive unit a factory buys — see DG vs grid vs solar per unit.
Time-of-day shifting
Where ToD tariffs apply, charging from midday solar and discharging into peak-rate evening hours stacks a second saving on top of peak shaving.
Storage also carries critical loads through an outage: the backed-up circuit, the hours it must run and the chemistry's usable depth of discharge set the bank size. That backup case is covered on our solar battery and hybrid storage page.
BESS sizing — kW and kWh are separate decisions
Power (kW) and energy (kWh) are separate ratings. A battery with plenty of kWh but too little kW cannot shave a sharp peak; one with high kW and thin kWh runs dry in the middle of it. The right size falls out of three curves laid over each other: your interval-metered load profile, your solar generation profile and your tariff — demand charges, ToD slabs and penal rates.
The honest exercise is unglamorous: a month or more of logged interval data, a realistic cycle count per day, and a warranty read closely enough to know what it covers. A battery cycled daily for peak shaving works far harder than a backup battery, and warranties are written around cycles, depth of discharge and throughput.
Fire separation — a BESS container is a fire load
A lithium container needs separation distances, thermal-runaway detection and a suppression scheme. Parking it against the factory wall because that is where the cable run was shortest is how a battery becomes an insurance problem. The battery room or container position, its ventilation and its detection are planned with the electrical layout, not after it.
The fire-safety rules for lithium batteries indoors are in our lithium battery room fire-safety guide, and the suppression side is the same discipline as our fire fighting systems work.
Choosing among BESS companies in India — what to put in the RFQ
BESS quotes arrive in very different shapes, and the differences hide in the annexures. Ask every bidder to state, in writing:
- Usable energy at system level — not cell nameplate, which round-trip losses and depth-of-discharge limits shrink
- Continuous and peak discharge power
- Warranted throughput or cycle count at a stated depth of discharge
- The degradation curve to year ten
- Auxiliary consumption of the container's own cooling — a running cost all year
- The fire detection and suppression scheme, with the separation distances the vendor's manual demands
The balance of system matters as much: the paralleling switchgear, the protection settings and the DISCOM intimation for a grid-interactive battery are electrical engineering scope. Projects go badly when nobody owns that scope — battery vendors often leave it as "by others". It is the part of the job our electrical contracting team does every day.
Solar battery storage for a factory — now or later
If you already have rooftop solar, storage is an add-on decision: the inverter architecture — AC-coupled retrofit or DC-coupled — is settled by what is on your roof. If you are planning solar now, deciding on storage-readiness at design stage costs very little and keeps the option open.
Start with the plant: industrial rooftop solar EPC for HT-connected plants, or solar panels for factories for whether the arithmetic works. For architects specifying storage on a commercial building, see BESS and solar storage in commercial buildings.
BESS projects, engineered as part of the plant
- Sizing from your load profile, tariff and the loads that must ride through an outage
- Chemistry and capacity, the hybrid inverter or PCS, and the battery management system
- Critical loads wired onto the backed-up circuit; protection and DG interplay designed in
- Container or battery-room position, ventilation and fire precautions
- Commissioning through a simulated outage, with charge and discharge limits set to protect cycle life
- Handover of the sizing calculation, the settings record and the operating limits
Our published project records do not yet include a standalone BESS installation. What we bring is the electrical and fire engineering a battery sits inside, on industrial plants, for 15+ years.
Battery energy storage — straight answers
What is a battery energy storage system (BESS)?
A battery bank with its power conversion system, battery management system and controls, installed to store energy — from rooftop solar or the grid — and release it when it is worth more: at your demand peak, during an outage, or in an expensive tariff slot. For industry it is usually a containerised lithium system tied into the plant's LT distribution.
Does a BESS pay back for a factory?
It can, where the factory pays demand charges or penalties for exceeding contract demand, runs DG sets regularly, or has a time-of-day tariff with expensive evening slots. Lithium cell prices have fallen for years, and for facilities already paying demand penalties or running DGs daily, paybacks are now measured in years rather than decades. A plant with a flat daytime load and a reliable grid may not need one yet — the answer comes from your interval-metered load profile, not a rule of thumb.
How is a BESS sized — kW or kWh?
Both, separately. Power (kW) decides whether the battery can cut a sharp peak; energy (kWh) decides how long it can hold it. A battery with plenty of kWh but too little kW cannot shave the peak; one with high kW and thin kWh runs dry halfway through it. We size from three curves laid over each other — your logged load profile, your solar generation profile and your tariff structure — using a month or more of interval data.
LFP or lead-acid batteries?
For a battery that cycles daily — peak shaving or load shifting — lithium iron phosphate (LFP) is the usual choice because it allows a deeper usable discharge. Tubular lead-acid can still suit occasional backup on a tighter budget. Our battery calculator assumes about 80% usable depth of discharge for LFP and about 50% for lead-acid; the warranty's cycle and throughput terms decide the real comparison.
Can a BESS be added to an existing rooftop solar plant?
Yes. The inverter architecture — an AC-coupled retrofit or a DC-coupled system — is settled by what is on your roof today. If you are planning solar now, making it storage-ready at design stage (inverter selection, spare panel capacity, a container position earmarked with fire separation in mind) costs very little and keeps the option open.
Where can the battery container go?
Where the fire engineering allows, not where the cable run is shortest. A lithium BESS container is a significant fire load: it needs separation distances, thermal-runaway detection and a suppression scheme, and the vendor's own manual sets distances that the layout must respect. We plan the container position, the detection and the suppression alongside the electrical design.
Find out whether storage pays on your load
Send a recent electricity bill and, if you have it, a month of interval data from your meter. We will tell you what a battery can shave, what it would cost to run, and whether it is worth it yet.