Delhi Solar Calculator (BSES Rajdhani)

Rooftop solar payback for South and West Delhi homes on BSES Rajdhani, with the Delhi top-up, generation incentive and BRPL's PPAC.

Your home

Average monthly electricity bill

₹

₹100₹50K

About 498 units a month on the BSES Rajdhani tariff. Use a year's average if your bill swings with the seasons.

Roof type

RCC flat roof

RCC, elevated structure

Metal sheet roof

Fine-tune

System size

Sized to cover a year of your consumption, at 5.1 peak sun hours a day in Delhi.

Usable shadow-free roof area (optional)

sq ft

About 100 sq ft per kW. Leave at 0 for no limit.

Installed cost per kW, GST included

₹

Typical for an on-grid system from an empanelled vendor. Replace it with your quote.

Yearly rise in electricity prices

0%15%

Indian residential tariffs have historically risen 4-7% a year.

Panel output lost each year

0%2%

Monocrystalline panels typically lose about 0.5% a year.

How you pay

Upfront

Solar loan

Pays for itself in1.2 yearsthen ₹16.67 L ahead after 25 years

A 4 kW system makes about 478 units a month, 96% of your use. Your bill drops from ₹3,000 to about ₹0 in year one.

Installed cost: ₹2,20,000
PM Surya Ghar subsidy: − ₹78,000
State top-up: − ₹78,000; Delhi Government top-up to PM Surya Ghar
Net cost to you: ₹64,000
Saving in year one: ₹53,203
Return (IRR): 85.1% a year; over 25 years, before tax
CO₂ avoided: 97 tonnes; over 25 years

Subsidy71%

You pay29%
Central subsidy35%
State top-up35%

Your money over 25 yearsStill to recoverAhead

Year-by-year cash flowShow

Year	Units made	Bills without solar	Bills with solar	Upkeep and EMIs	Running total
1	5,733	₹36,003	₹0	₹0	-₹10,797
2	5,705	₹37,803	₹0	₹0	₹44,121
3	5,676	₹39,693	₹0	₹0	₹1,00,843
4	5,648	₹41,678	₹0	₹0	₹1,59,464
5	5,620	₹43,762	₹0	₹0	₹2,20,085
6	5,592	₹45,950	₹0	₹2,200	₹2,63,835
7	5,564	₹48,247	₹0	₹2,200	₹3,09,882
8	5,536	₹50,660	₹0	₹2,200	₹3,58,342
9	5,508	₹53,193	₹0	₹2,200	₹4,09,335
10	5,481	₹55,852	₹0	₹2,200	₹4,62,987
11	5,453	₹58,645	₹0	₹2,200	₹5,19,433
12	5,426	₹61,577	₹0	₹30,200	₹5,50,810
13	5,399	₹64,656	₹0	₹2,200	₹6,13,266
14	5,372	₹67,889	₹0	₹2,200	₹6,78,955
15	5,345	₹71,283	₹0	₹2,200	₹7,48,039
16	5,318	₹74,848	₹0	₹2,200	₹8,20,686
17	5,292	₹78,590	₹0	₹2,200	₹8,97,076
18	5,265	₹82,520	₹0	₹2,200	₹9,77,396
19	5,239	₹86,646	₹0	₹2,200	₹10,61,841
20	5,213	₹90,978	₹0	₹2,200	₹11,50,619
21	5,187	₹95,527	₹0	₹2,200	₹12,43,946
22	5,161	₹1,00,303	₹0	₹2,200	₹13,42,049
23	5,135	₹1,05,318	₹0	₹2,200	₹14,45,167
24	5,109	₹1,10,584	₹0	₹2,200	₹15,53,551
25	5,084	₹1,16,113	₹0	₹2,200	₹16,67,464

How it works

The bill you enter is worked backwards through your DISCOM's slabs, fixed charges, surcharges and duty to the units you use. The panels' yearly output is set against that use under net metering, and each month is re-billed on what is left. Because the units solar removes come off your most expensive slab first, the saving per unit is often well above the average rate on your bill. Tariffs rise by the escalation rate each year while the panels slowly lose output; maintenance, an inverter replacement in year 12 and any loan repayments are taken off, and the running total gives the payback year.

Saving₍y₎ = [Bill(U) − Bill(U − G₍y₎/12)] × 12 × (1 + e)^(y−1),  G₍y₎ = kW × H × 365 × PR × (1 − d)^(y−1)

U: Units you use a month, worked out from your bill
G₍y₎: Units the panels make in year y
H: Peak sun hours a day in your state
PR: Performance ratio: the share of rated output that reaches the meter, 0.77 here
e: Yearly rise in electricity prices
d: Yearly loss in panel output

Worked example

A Delhi home on BSES Rajdhani with a ₹3,500 monthly bill and a flat RCC roof, assuming prices rise 5% a year.

1Working the bill back through the BSES Rajdhani slabs, charges and duty gives about 557 units a month
2At 5.1 peak sun hours, 4.5 kW makes about 538 units a month, 97% of that use
34.5 kW at ₹55,000 per kW costs ₹2,47,500; PM Surya Ghar pays ₹78,000 and the Delhi Government top-up to PM Surya Ghar ₹78,000, leaving ₹91,500
4The first year saves ₹61,390, and the saving grows as tariffs rise

The system pays for itself in about 1.5 years and leaves the household about ₹19,29,746 ahead over 25 years.

Frequently asked questions

Is BSES Rajdhani more expensive than Tata Power-DDL?

The slab rates are the same across Delhi because DERC sets them, but the PPAC differs by DISCOM. BRPL was allowed 17.94% from June 2026 against TPDDL's 16%, so the same consumption costs slightly more on BSES Rajdhani and solar saves slightly more.

How do I apply for rooftop solar with BSES Rajdhani?

Register on the PM Surya Ghar portal with your BRPL CA number, choose an empanelled vendor, and apply for net metering through the portal. After installation BRPL inspects the system and fits a net meter; the central subsidy follows once it is commissioned, and the Delhi top-up through the state's own process.

How does net metering settle on BSES Rajdhani?

Net metering with a yearly settlement, plus a generation-based incentive under the Delhi Solar Policy paid on every unit the panels produce for the first five years.

How much is the PM Surya Ghar subsidy?

₹30,000 per kW for the first 2 kW and ₹18,000 for the third, so ₹30,000 for 1 kW, ₹60,000 for 2 kW and ₹78,000 for 3 kW or more. It is paid into your bank account after the DISCOM inspects and commissions the system, and only for installations by an empanelled vendor using ALMM-listed panels, applied for through pmsuryaghar.gov.in.

Why is my saving per unit higher than my average rate?

Residential tariffs are telescopic: the first units are cheap and each slab above costs more. Solar takes units off the top of your bill, so it removes the dearest ones first. A home in a ₹10-plus slab saves that rate on every unit the panels cover, even if the bill averages out lower.

Why not simply fit the biggest system my roof will hold?

The central subsidy stops rising at 3 kW, and under net metering surplus units are usually bought back at the regulator's average power purchase cost, often ₹2-3 a unit, far below what you pay for grid power. Sizing to your own consumption earns the full retail rate on every unit. The calculator suggests that size; override it to see what a bigger system does to the return.