Solar plants make power during the day, but many factories run through the night. Banking lets you deposit surplus solar units with the grid when you can’t use them and draw the same units back later, like a savings account for electricity.
How states charge for it
States recover the cost in one of two ways: they keep a share of the banked units, or they charge a fee per unit. Karnataka currently allows monthly banking subject to a 4% charge under a High Court direction. Gujarat charges about ₹1.50 a unit.
Example
A plant sends you 1 lakh units in a month, but you can only use 70,000 in daylight. You bank the other 30,000. At a 4% charge you get back 28,800 units at night, so the 1,200 lost units add to your cost per unit.
Why the rules matter
- Monthly banking is far more useful than daily banking, because you can balance cloudy and sunny days.
- Some states limit when banked units can be drawn, for example not during evening peak hours.
- Banking rules are often challenged in court. Maharashtra’s are before the Bombay High Court, so a contract should say what happens if they change.
Related: open access, landed cost.
Sources
Figures last checked on 26 September 2026.