Delhi Solar Calculator (TPDDL)
Rooftop solar payback for North Delhi homes on Tata Power-DDL, with the Delhi top-up, generation incentive and 200-unit subsidy.
Updated · By Niraj Kumar · 1 source
https://checkpre.com/energy/solar-calculator-delhi-tpddl
Your home
About 504 units a month on the TPDDL tariff. Use a year's average if your bill swings with the seasons.
Fine-tune
Sized to cover a year of your consumption, at 5.1 peak sun hours a day in Delhi.
About 100 sq ft per kW. Leave at 0 for no limit.
Typical for an on-grid system from an empanelled vendor. Replace it with your quote.
Indian residential tariffs have historically risen 4-7% a year.
Monocrystalline panels typically lose about 0.5% a year.
A 4 kW system makes about 478 units a month, 95% 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
- ₹53,248
- Return (IRR)
- 85.2% a year
- over 25 years, before tax
- CO₂ avoided
- 97 tonnes
- over 25 years
- You pay29%
- Central subsidy35%
- State top-up35%
Year-by-year cash flowShowHide
| Year | Units made | Bills without solar | Bills with solar | Upkeep and EMIs | Running total |
|---|---|---|---|---|---|
| 1 | 5,733 | ₹36,048 | ₹0 | ₹0 | -₹10,751 |
| 2 | 5,705 | ₹37,851 | ₹0 | ₹0 | ₹44,214 |
| 3 | 5,676 | ₹39,743 | ₹0 | ₹0 | ₹1,00,986 |
| 4 | 5,648 | ₹41,730 | ₹0 | ₹0 | ₹1,59,660 |
| 5 | 5,620 | ₹43,817 | ₹0 | ₹0 | ₹2,20,336 |
| 6 | 5,592 | ₹46,008 | ₹0 | ₹2,200 | ₹2,64,143 |
| 7 | 5,564 | ₹48,308 | ₹0 | ₹2,200 | ₹3,10,252 |
| 8 | 5,536 | ₹50,724 | ₹0 | ₹2,200 | ₹3,58,775 |
| 9 | 5,508 | ₹53,260 | ₹0 | ₹2,200 | ₹4,09,835 |
| 10 | 5,481 | ₹55,923 | ₹0 | ₹2,200 | ₹4,63,558 |
| 11 | 5,453 | ₹58,719 | ₹0 | ₹2,200 | ₹5,20,077 |
| 12 | 5,426 | ₹61,655 | ₹0 | ₹30,200 | ₹5,51,532 |
| 13 | 5,399 | ₹64,738 | ₹0 | ₹2,200 | ₹6,14,070 |
| 14 | 5,372 | ₹67,975 | ₹0 | ₹2,200 | ₹6,79,844 |
| 15 | 5,345 | ₹71,373 | ₹0 | ₹2,200 | ₹7,49,017 |
| 16 | 5,318 | ₹74,942 | ₹0 | ₹2,200 | ₹8,21,759 |
| 17 | 5,292 | ₹78,689 | ₹0 | ₹2,200 | ₹8,98,248 |
| 18 | 5,265 | ₹82,624 | ₹0 | ₹2,200 | ₹9,78,672 |
| 19 | 5,239 | ₹86,755 | ₹0 | ₹2,200 | ₹10,63,227 |
| 20 | 5,213 | ₹91,092 | ₹0 | ₹2,200 | ₹11,52,119 |
| 21 | 5,187 | ₹95,647 | ₹0 | ₹2,200 | ₹12,45,566 |
| 22 | 5,161 | ₹1,00,429 | ₹0 | ₹2,200 | ₹13,43,795 |
| 23 | 5,135 | ₹1,05,451 | ₹0 | ₹2,200 | ₹14,47,046 |
| 24 | 5,109 | ₹1,10,723 | ₹0 | ₹2,200 | ₹15,55,570 |
| 25 | 5,084 | ₹1,16,260 | ₹0 | ₹2,200 | ₹16,69,629 |
How the Delhi Solar Calculator (TPDDL) works
Saving₍y₎ = [Bill(U) − Bill(U − G₍y₎/12)] × 12 × (1 + e)^(y−1), G₍y₎ = kW × H × 365 × PR × (1 − d)^(y−1)This page uses the same method as the Solar ROI Calculator India, which explains each term and assumption in full.
Worked example
A Delhi home on TPDDL with a ₹3,000 monthly bill and a flat RCC roof, assuming prices rise 5% a year.
- 1Working the bill back through the TPDDL slabs, charges and duty gives about 504 units a month
- 2At 5.1 peak sun hours, 4 kW makes about 478 units a month, 95% of that use
- 34 kW at ₹55,000 per kW costs ₹2,20,000; PM Surya Ghar pays ₹78,000 and the Delhi Government top-up to PM Surya Ghar ₹78,000, leaving ₹64,000
- 4The first year saves ₹53,248, and the saving grows as tariffs rise
The system pays for itself in about 1.2 years and leaves the household about ₹16,69,629 ahead over 25 years.
Frequently asked questions
How does Delhi's 200-unit free electricity interact with solar?
Delhi pays the whole bill for homes using 200 units or fewer in a month and half the bill, up to ₹800, between 201 and 400. Solar that brings a 500-unit home's net use down below 200 therefore wipes out more than the units it replaces: the bill drops to zero. The calculator applies both tiers to the net units after solar.
What is PPAC and why does it matter for solar?
The Power Purchase Adjustment Cost is a percentage surcharge on energy and fixed charges that DERC lets DISCOMs levy as power costs rise; for TPDDL it is 16% from June 2026, on top of the 7% pension trust surcharge. Every unit solar removes also removes its share of these surcharges.
How does net metering settle on TPDDL?
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.
Sources
Related calculators
- Solar ROI Calculator IndiaEnter your electricity bill and state to see the rooftop system you need, your PM Surya Ghar subsidy, payback period and 25-year return.
- 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.
- Uttar Pradesh Solar Calculator (UPPCL)Rooftop solar payback for Lucknow, Noida and the rest of Uttar Pradesh, with the UPNEDA top-up of ₹15,000 a kW on UPPCL's slabs.
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