Featured in Cleantech Hero: Why Battery Sizing Can't Run on Annual Averages
Cleantech Hero featured Ingro co-founder and CEO Ankit Mittal on why battery sizing can't come from annual averages: storage earns its money in the gap between cheap hours and expensive ones, and an average erases exactly that gap.
Ingro Energy co-founder and CEO Ankit Mittal was featured in Cleantech Hero, in a piece on one of the most common mistakes in sizing battery storage: building the case on annual averages.
His argument is simple. A battery does not earn its return across an average day. It earns it in the gap between the hours when power is cheap and the hours when it is expensive. Average a year's consumption, generation and tariffs into a single figure, and that gap — the very thing storage is paid for — disappears from the model.
Why averages hide the value of storage
Storage is a timing asset. It charges when energy is cheap or solar is plentiful, and discharges when the site would otherwise buy expensive grid power. An annual-average model flattens those hours together, so it cannot see:
- when solar output and site load actually line up, and when they don't
- how wide the spread is between cheap hours and expensive ones under the site's tariff
- how many hours a day the battery is genuinely needed, and at what power
Get those wrong and the battery is either oversized, with capital sitting idle, or undersized, leaving the most expensive hours still on the grid.
Comparing futures, not averages
The feature was illustrated with figures from Ingro's sizing work: one view showing load, solar generation and battery charge and discharge across the day, alongside 46% annual grid cost savings, a 98% peak-zone grid cost reduction and a 3.4-year payback on battery capex.
A second graphic, using sample figures from Ingro Sims, priced three futures for one C&I site across twelve months of bills:
- Today (grid only): annual bill of ₹3.9 Cr
- Solar only (2.4 MWp): annual bill of ₹3.1 Cr, saving ₹80 L a year
- Solar + battery (2.4 MWp + 1.8 MWh), recommended: annual bill of ₹2.8 Cr, saving ₹1.1 Cr a year with a 3.2-year payback
Built into Ingro Sims
This is the thinking behind Ingro Sims, Ingro's solar and storage sizing platform built for India: model the site's own year hour by hour, price it on its actual tariff, and let the gap between cheap and expensive hours decide how much storage pays.
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