Is Solar Worth It in Punjab With 300 Free Units?

Punjab gives homes 300 free units of electricity a month (600 on a two-month bill). More than anything else, that decides whether rooftop solar is worth buying here, and most solar advertising leaves it out.

Bills and payback at different usage levels

Look at how far the bill jumps between 300 and 305 units; those figures are correct. The payback column is worth a second look too. It gets shorter as usage rises, even though the system stays at 3 kW.

Why one unit over the line costs so much

For general-category homes the free units are all or nothing. Stay at or under 300 units a month and you pay nothing at all: no energy charges, fixed charges, meter rent or duty. Go one unit over and PSPCL charges energy on every unit you used, starting from the first, plus fixed charges and duty.

A home at 320 units therefore pays for all 320, including the first 300.

(SC, BC, non-SC BPL and Freedom Fighter households are treated differently. They pay only for the units above 300, plus fixed charges, so their jump is smaller, though the same logic applies.)

Why payback is fastest nearer 600 units

RSK Solar Energy’s smallest on-grid system is 3 kW. For a general-category home anywhere from just over 300 units to roughly 550 or 600 units a month, we recommend that same 3 kW system, at the same price, however far over the line you are.

Take two homes with the same 3 kW system at the same net price. One uses 305 units a month and pays about ₹1,880; solar saves it about ₹22,500 a year and pays back in roughly 4.4 to 5.2 years. The other uses 450 units and pays about ₹3,030; the same system saves it about ₹36,400 a year and pays back in roughly 2.7 to 3.2 years. The second home paid the same for its system and simply had a bigger bill to get rid of.

Solar pays back well anywhere from just over 300 units to around 600, and fastest towards the top of that range. Past about 600 units the recommended system gets bigger and the price goes up with it, so payback stops improving.

If you are only just over 300, say 305 to 350 units, solar still clears the bill and still pays back in reasonable time (see the table above). You are buying a little more capacity than you strictly need, though, because our on-grid range starts at 3 kW. If a smaller system would suit you better, off-grid is available from 1 kW, without the subsidy; see on-grid vs off-grid vs hybrid.

Under the line: when solar still makes sense

• Your use is about to go up. A new air conditioner, an EV, an extension or a bigger family can push you over 300 units, and at that point every unit is charged.
• Power cuts cost you. A hybrid system with batteries keeps the essentials running and still gets the same PM Surya Ghar subsidy as on-grid. What you are paying for is backup, since under the free-units line there is no bill left to cut.
• You sit close to the line. Any month that crosses 300 brings a full bill, so check your hottest two-month bill as well as your average.

One thing to confirm

All of this assumes PSPCL applies the 300 free units to your net units after solar, which is how net-metered bills are normally worked out. We check it against real post-solar bills for your connection before quoting.

Check your own bill

The calculator runs these numbers for you. It tells you whether you are under the line and, if you are over it, the smallest system that takes your bill to zero.