Banking is ending. Here is what replaces it.
The grid used to store your midday surplus for free. As that is withdrawn state by state, the mismatch between solar noon and factory evening gets a price — and a private answer.
For most of the last decade, the grid was your battery, and it worked for free. Solar made at noon that your plant could not absorb was credited to the DISCOM and drawn back in the evening — a service called banking, priced at little or nothing. It is the quiet assumption inside almost every solar business case written before 2024, and it is being withdrawn.
What is actually changing
Not one rule — a direction, moving state by state. Banking windows have shortened from annual to monthly or quarterly, so surplus made in March can no longer offset a bill in June. Banking charges have appeared and risen. Settlement has migrated from net metering toward net billing, where an exported unit earns a rate well below the rate you pay to import one. Maharashtra has gone furthest, mandating co-located storage for new C&I solar above 100 kW from April 2026.
Each state moves at its own pace and under its own order — which is why we confirm the position against your state's current regulations before sizing anything. But the direction is one-way, and business cases built on generous banking are ageing badly.
The arithmetic of the gap
A factory's load runs into the evening; solar does not. Under old-style banking that mismatch cost you nothing — the grid absorbed noon and returned it at seven. Under net billing, the same mismatch has a price: your midday surplus is bought from you cheaply, and your evening units are sold to you at the full tariff. The spread between those two numbers, multiplied by every mismatched unit, is what the withdrawal of banking costs a C&I consumer per year.
There are two responses. Size the plant down so nothing is ever exported — safe, but it caps the saving at your daytime load. Or keep the size and store the surplus.
What a battery is for — and what it is not
A commercial battery on a C&I plant is not backup power. It is a settlement instrument: it takes the midday units net billing would buy from you cheaply, and returns them into the evening block you would otherwise buy at your full tariff. It replaces, privately and on your side of the meter, the service the grid used to provide free — except the economics are now yours rather than the DISCOM's.
Sizing it is a load-shape question, not a rule of thumb. The solar-and-storage simulator on our project models page shows the mechanics on your own numbers: generation curve, load curve, and what the battery moves between them.
When it does not pay
Honestly: not every site should buy storage today. If your state still offers workable banking, if your load is concentrated in daylight hours, or if your surplus is small, a battery is an expense in search of a problem — and we will say so. The cases that already clear are the ones with a real evening block, a shrinking banking window, or a Maharashtra-style mandate arriving on a date you can read.
Where we stand
Every plant we deliver is engineered storage-ready, so the battery is an addition, not a rebuild. Our first co-located BESS — 7.5 MWh at 33 kV — is in commissioning at the Chamu park, and the operating dispatch experience from it flows into every storage proposal we write after it.
The regime that applies to you is set by your state commission and can change with a single order. We verify the current position — banking window, charges, settlement basis — against the applicable regulations before any proposal is priced.
Take the twenty-question checklist with you. Printable, one page per section, and nothing in it is specific to Vibgyor — run it against us too.
Send us twelve months of bills.
Send twelve months of bills and your state, and we will tell you what the withdrawal of banking is costing you — and whether a battery pays it back. The analysis comes back free, with no commitment.