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Kolkata Solar Calculator (CESC)

Rooftop solar payback for Kolkata and Howrah homes on CESC, with its seven-band tariff and the FPPA surcharge.

Updated · By Niraj Kumar · 1 source

Your home

Solar forSolar for
From your bill, enterFrom your bill, enter
₹
₹100₹50K

About 340 units a month on the CESC tariff. Use a year's average if your bill swings with the seasons.

Roof typeRoof type

Fine-tune

kW

Sized to cover a year of your consumption, at 4.6 peak sun hours a day in West Bengal.

sq ft

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.

%
0%15%

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

%
0%2%

Monocrystalline panels typically lose about 0.5% a year.

How you payHow you pay
Pays for itself in2.9 yearsthen ₹13.88 L ahead after 25 years

A 3 kW system makes about 323 units a month, 95% of your use. Your bill drops from ₹3,000 to about ₹153 in year one.

Installed cost
₹1,80,000
PM Surya Ghar subsidy
− ₹78,000
Net cost to you
₹1,02,000
Saving in year one
₹34,186
Return (IRR)
37.7% a year
over 25 years, before tax
CO₂ avoided
66 tonnes
over 25 years
Subsidy43%
  • You pay57%
  • Central subsidy43%
Your money over 25 yearsStill to recoverAhead
₹-5 L₹0₹5 L₹10 L₹15 LPayback, year 2.904812162025
Year-by-year cash flowShow
YearUnits madeBills without solarBills with solarUpkeep and EMIsRunning total
13,878₹36,022₹1,836₹0-₹67,814
23,859₹37,823₹2,054₹0-₹32,045
33,840₹39,714₹2,288₹0₹5,382
43,821₹41,700₹2,539₹0₹44,544
53,802₹43,785₹2,809₹0₹85,520
63,782₹45,974₹3,099₹1,800₹1,26,595
73,764₹48,273₹3,424₹1,800₹1,69,645
83,745₹50,687₹3,774₹1,800₹2,14,757
93,726₹53,221₹4,150₹1,800₹2,62,028
103,707₹55,882₹4,553₹1,800₹3,11,557
113,689₹58,676₹4,986₹1,800₹3,63,448
123,670₹61,610₹5,449₹22,800₹3,96,810
133,652₹64,691₹5,944₹1,800₹4,53,756
143,634₹67,925₹6,474₹1,800₹5,13,407
153,616₹71,321₹7,042₹1,800₹5,75,886
163,598₹74,888₹7,649₹1,800₹6,41,325
173,580₹78,632₹8,297₹1,800₹7,09,861
183,562₹82,564₹8,989₹1,800₹7,81,635
193,544₹86,692₹9,729₹1,800₹8,56,797
203,526₹91,026₹10,519₹1,800₹9,35,505
213,509₹95,578₹11,362₹1,800₹10,17,921
223,491₹1,00,357₹12,261₹1,800₹11,04,216
233,474₹1,05,374₹13,219₹1,800₹11,94,571
243,456₹1,10,643₹14,242₹1,800₹12,89,173
253,439₹1,16,175₹15,331₹1,800₹13,88,217

How the Kolkata Solar Calculator (CESC) 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 Kolkata home on CESC with a ₹2,500 monthly bill and a flat RCC roof, assuming prices rise 5% a year.

  1. 1Working the bill back through the CESC slabs, charges and duty gives about 293 units a month
  2. 2At 4.6 peak sun hours, 2.5 kW makes about 269 units a month, 92% of that use
  3. 32.5 kW at ₹60,000 per kW costs ₹1,50,000; PM Surya Ghar pays ₹69,000, leaving ₹81,000
  4. 4The first year saves ₹27,655, and the saving grows as tariffs rise

The system pays for itself in about 2.8 years and leaves the household about ₹11,19,291 ahead over 25 years.

Frequently asked questions

Is rooftop solar worth it in Kolkata?

Usually, though the payback is longer than in western India. Kolkata gets about 4.6 peak sun hours a day against 5.8 in Gujarat, so each kW makes fewer units. CESC's tariff is high from the first unit, about ₹5.18 rising to ₹9.21 above 300 units, which keeps the saving per unit strong.

Can a Kolkata apartment use net metering?

Individual flats rarely have their own roof. A housing society can install a system for its common areas, such as lifts, pumps and lighting, and claim ₹18,000 a kW from PM Surya Ghar. The housing society solar calculator covers the shared case.

How does net metering settle on CESC?

Net metering under WBERC's regulations, with surplus units carried forward and settled at the end of the year.

Sources

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