CheckPre

Kerala Solar Calculator (KSEB)

Rooftop solar payback for Kerala on KSEB, where crossing 250 units a month moves every unit to a flat, higher rate.

Updated · By Niraj Kumar · 1 source

Your home

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

About 323 units a month on the KSEB tariff. KSEB bills every two months: enter a month's share.

Roof typeRoof type

Fine-tune

kW

Sized to cover a year of your consumption, at 5 peak sun hours a day in Kerala.

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 in2.7 yearsthen ₹15.31 L ahead after 25 years

A 3 kW system makes about 351 units a month, 100% of your use. Your bill drops from ₹3,000 to about ₹55 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
₹36,425
Return (IRR)
40.0% a year
over 25 years, before tax
CO₂ avoided
72 tonnes
over 25 years
Subsidy43%
  • You pay57%
  • Central subsidy43%
Your money over 25 yearsStill to recoverAhead
₹-5 L₹0₹5 L₹10 L₹15 L₹20 LPayback, year 2.704812162025
Year-by-year cash flowShow
YearUnits madeBills without solarBills with solarUpkeep and EMIsRunning total
14,216₹35,998₹660₹0-₹65,575
24,195₹37,798₹693₹0-₹27,451
34,174₹39,687₹728₹0₹12,462
44,153₹41,672₹764₹0₹54,255
54,132₹43,755₹802₹0₹98,028
64,111₹45,943₹842₹1,800₹1,42,082
74,091₹48,240₹884₹1,800₹1,88,326
84,070₹50,652₹929₹1,800₹2,36,871
94,050₹53,185₹975₹1,800₹2,87,838
104,030₹55,844₹1,024₹1,800₹3,41,351
114,010₹58,636₹1,075₹1,800₹3,97,540
123,990₹61,568₹1,129₹22,800₹4,35,543
133,970₹64,647₹1,185₹1,800₹4,97,504
143,950₹67,879₹1,245₹1,800₹5,62,575
153,930₹71,273₹1,307₹1,800₹6,30,914
163,910₹74,837₹1,372₹1,800₹7,02,689
173,891₹78,579₹1,441₹1,800₹7,78,074
183,871₹82,507₹1,553₹1,800₹8,57,228
193,852₹86,633₹1,807₹1,800₹9,40,254
203,833₹90,964₹2,082₹1,800₹10,27,336
213,814₹95,513₹2,379₹1,800₹11,18,669
223,795₹1,00,288₹2,700₹1,800₹12,14,458
233,776₹1,05,303₹3,046₹1,800₹13,14,915
243,757₹1,10,568₹3,418₹1,800₹14,20,265
253,738₹1,16,096₹3,819₹1,800₹15,30,743

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

  1. 1Working the bill back through the KSEB slabs, charges and duty gives about 300 units a month
  2. 2At 5 peak sun hours, 2.5 kW makes about 293 units a month, 98% 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 ₹29,040, and the saving grows as tariffs rise

The system pays for itself in about 2.7 years and leaves the household about ₹12,13,334 ahead over 25 years.

Frequently asked questions

What happens at 250 units a month on KSEB?

Below 250 units a month the tariff is telescopic, from ₹3.35 to ₹8.50. Above it every unit is charged at one flat rate, from ₹6.75 at 300 units up to ₹9.20 above 500, and the fixed charge jumps too. Solar that brings net use back under 250 saves far more than the units alone.

Does Kerala's monsoon hurt solar output?

Yes. June to September produce noticeably less, which is why Kerala's yearly average is lower than Rajasthan's or Gujarat's. Net metering banks the summer surplus against the monsoon shortfall, so the yearly figure the calculator uses is the one that matters.

How does net metering settle on KSEB?

Net metering on a bi-monthly bill, with the surplus settled yearly at the KSERC-approved average power purchase cost.

Sources

Related calculators

More in Energy, Solar & EV