While the industry talks about gigawatt-hour projects in Rajasthan, India’s largest deployment of batteries by number of installations is sitting on rooftops and roadsides in every district of the country, powering mobile networks.
It is not glamorous and it rarely makes headlines. It is also a useful window into what distributed storage actually looks like at scale.
The numbers behind it
India had over 854,662 telecom towers as of mid-March, according to Department of Telecommunications data on passive infrastructure.
Every one of them needs power continuously. Where the grid is unreliable — which is much of rural and semi-urban India — the traditional answer has been a diesel generator and a bank of lead-acid batteries. Estimates place the telecom sector’s annual diesel consumption in the range of several billion litres.
That is the prize. Displacing even a fraction of it with batteries is worth a great deal, and it is why the operators have been moving.
What the operators are doing
Airtel reported in its Q4 FY26 results, in May 2026, that it was intensifying efforts to cut diesel consumption in collaboration with tower infrastructure provider Indus Towers, transitioning to high-powered batteries and alternate sources of energy.
The solar build-out has moved alongside it: Airtel has solarised nearly 27,000 network sites in two years and now has around 42,000 sites with solar access.
Indus Towers has been pushing on both energy and cooling — its “Shut AC” initiative moves sites to free cooling units, and it has been transitioning sites toward diesel-generator-free operation using advanced battery bank solutions and fuel-cell-based generators. It has also backed longer-term research, signing an agreement with IIT Bombay covering perovskite solar cell technology and scalable methods for converting rice straw into hard carbon materials for energy storage.
Why lithium is displacing lead-acid
Telecom sites ran on lead-acid for decades. The switch is happening for reasons that generalise well beyond towers.
Space and weight. Lithium banks deliver the same backup in roughly a third of the space and weight of lead-acid. On a rooftop or shared site with structural loading limits, that is frequently the difference between a viable installation and no installation at all.
Cycle life. A tower in an area with daily grid interruptions cycles its battery daily. Lead-acid degrades quickly under that duty; lithium tolerates it far better. Our comparison of lithium versus lead-acid for solar storage covers the trade-offs in detail.
Depth of discharge. Lead-acid suffers if regularly discharged deeply, so a large part of its nameplate capacity is effectively unusable. Lithium’s usable fraction is much higher — the mechanics are in C-rate, depth of discharge and state of charge.
Theft. Lead-acid batteries have long had a resale value that makes remote sites a target. Lithium banks are less attractive to steal and are usually better monitored.
What this market teaches the rest of the industry
The tower market is a preview of distributed storage generally, and three lessons carry across.
Service beats specification. Hundreds of thousands of sites across every terrain in India means the winning proposition is not the best datasheet — it is the ability to get a technician and a spare part to a remote site quickly. That is the same argument that matters for availability guarantees and spares.
Monitoring is not optional. Nobody visits these sites daily. Remote visibility into state of charge, health and alarms is what makes the asset manageable at all — the function of the BMS and EMS layers.
Heat is the enemy. Tower cabinets in Indian summers are brutal environments, which is why the operators’ cooling initiatives run alongside their battery ones. The same physics applies to every Indian installation, as covered in cooling a battery in Indian heat.
What this means for you
- If you are a tower operator or infrastructure provider: the economics now favour lithium on most sites with regular outages, and pairing with solar improves them further. The decision is increasingly about service model and monitoring, not about chemistry.
- If you are an equipment supplier: this market rewards logistics and service density over headline specification. Selling into it is a distribution problem.
- If you run any distributed asset base — bank branches, retail chains, cold chain, petrol stations — the tower case is a good proxy for yours. The same arithmetic of avoided generator runtime and avoided fuel applies, as does the comparison in BESS versus diesel genset.
- If you are sizing a small site: cabinet systems such as the ADESS 250 are built for exactly this class of installation, and our team can work through a multi-site rollout with you — get in touch.
Operator plans, deployment figures and sector diesel estimates change with reporting periods and vary by source. Treat this as an August 2026 snapshot and verify current figures with the operators and the Department of Telecommunications before relying on them.