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Rooftop solar in Kerala: subsidy, net metering and the 2026 billing rules

The central subsidy, what KSERC’s 2025 regulations changed for KSEB customers, how time-of-day normalisation and banking work since January 2026, grid support charges, the battery rules that start in April 2027, and how to apply.

Last updated: 22 October 2026 · Luminity

Kerala is one of the busiest rooftop solar markets in India. By 31 July 2026 it had 3,10,544 systems installed under the central PM Surya Ghar: Muft Bijli Yojana, with 1,203.02 MW of capacity covering 3,17,390 households and ₹2,073.80 crore of central subsidy released, according to figures the Ministry of New and Renewable Energy gave the Lok Sabha. Only Gujarat, Uttar Pradesh and Maharashtra had more installations; Kerala had 4,21,734 applications on the portal.

What changed is not the subsidy but the bill. The Kerala State Electricity Regulatory Commission (KSERC) notified the KSERC (Renewable Energy and Related Matters) Regulations, 2025 on 5 November 2025, after a draft that would have limited net metering to 3 kW drew strong protests from prosumers. The final rules keep net metering for homes up to 20 kW, but since 1 January 2026 they value exported power by time of day, charge for banking, and set battery requirements for bigger systems. They run until 31 March 2030.

As on 22 October 2026: central subsidy ₹30,000 per kW for the first 2 kW plus ₹18,000 for the third kW (maximum ₹78,000), with no state top-up for homes. Domestic net metering is allowed from 1 kW to 20 kW. Plants up to 2 kW are exempt from normalisation and plants up to 10 kW from grid support charges. Year-end surplus is paid at ₹2.79 a unit for new solar prosumers. Figures can change; KSEB, KSERC and the national portal have the final word.

What you get, by system size

Kerala gets the standard central rates. The table shows the central subsidy and the main regulatory thresholds that apply at each size for a domestic net-metering customer.

System size (inverter AC kW)	Central subsidy (₹)	Normalisation	Grid support charge	Storage required
1 kW	30,000	No	No	No
2 kW	60,000	No	No	No
3 kW	78,000	Yes	No	No
Above 3 kW, up to 5 kW	78,000 (maximum)	Yes	No	No
Above 5 kW, up to 10 kW	78,000 (maximum)	Yes	No; yes if feasibility is sought from 1 Apr 2027	No; 10% if feasibility is sought from 1 Apr 2027
Above 10 kW, up to 15 kW	78,000 (maximum)	Yes	Yes	10% of generation potential
Above 15 kW, up to 20 kW	78,000 (maximum)	Yes	Yes	20% of generation potential

Two details matter when you size a plant. KSERC measures a solar plant’s capacity on the AC side of the inverter, so a 3 kW inverter with slightly more panel capacity is still a 3 kW plant. And the plant cannot exceed your connected load. A single-phase inverter can connect at most 3 kW; anything larger needs a three-phase inverter, except that in areas without a three-phase network, single-phase inverters up to 5 kW are allowed for applicants seeking feasibility until 31 March 2027.

How billing works since January 2026

The regulations’ energy accounting rules took effect on 1 January 2026, and they cover existing prosumers as well as new ones. Your net meter records exports and imports in three zones:

Solar hours: 8 am to 6 pm.
Peak hours: 6 pm to 11.30 pm.
Off-peak hours: 11.30 pm to 8 am.

Power your plant generates is first used in your home. What you export in a zone is first set off against what you import in the same zone. Anything left over is banked, and here the time of day starts to count. For domestic prosumers, banked units are later taken back at 1.0 against solar-hour imports, 0.85 against off-peak imports and 0.75 against peak imports, and they are used in that order: solar hours first, then off-peak, then peak. Whatever import is still uncovered is billed at your normal tariff.

As an illustration of the rule: a home that banks 100 surplus units from the afternoon can cover 85 units of overnight use or 75 units of evening use with them, not 100. Homes with plants up to and including 2 kW are exempt, with a factor of 1 in every zone. KSERC says the zone system is meant to encourage use of power during solar hours and the installation of storage, and the factors can be revised along with the time-of-day tariff structure after consultation.

Banking, surplus and grid support charges

Each month, banked units are first used to cover the fixed and other charges on your bill so that you can reach a zero bill. Units left after that are carried forward to the next bill after a 2% monthly banking charge, until the end of the financial year. At year-end, KSEB pays for the remaining units before 30 April:

New solar prosumers: ₹2.79 a unit.
Existing prosumers: ₹3.08 a unit, the average power purchase cost the regulations set for them.
Carry-over: instead of payment, you can apply to carry the credit into the next financial year.

Grid support charges were the most disputed part of the draft. In the final version they apply only to energy drawn from the grid outside solar hours that is offset by banked energy. KSERC’s own example: if a prosumer draws 400 units at night and has 300 banked units after normalisation, the charge applies to 300 units. Until KSERC sets category-wise charges in a tariff order, the interim rate is 50 paise a unit for the first 300 units in a month and ₹1 a unit beyond that. Domestic plants up to 10 kW, existing or new, are exempt, as are all agricultural consumers. The exemption narrows for later applicants: plants above 5 kW that seek feasibility from 1 April 2027 will pay.

Fixed charges are a separate fight. In a September 2025 order (OP 43 of 2025), KSERC said domestic solar prosumers can pay fixed charges either on their total consumption, including self-used solar, or at ₹47 per kW a month on connected load, until it sets fixed charges based on recorded maximum demand. The Appellate Tribunal for Electricity dismissed a prosumer’s appeal against that order on 16 February 2026, while noting the case for KSERC to settle the demand-based fixed charge quickly.

Other options: net billing, gross metering and shared plants

Net metering is the usual choice for homes, but the regulations offer alternatives:

Net billing: imports are billed at your tariff and exports paid at a feed-in tariff of ₹3.07 a unit for solar.
Gross metering: all generation is sold to KSEB at ₹3.63 a unit for solar, or ₹7.50 a unit for power supplied at peak from storage.
Behind the meter: no export at all, with a reverse power relay, after prior intimation to KSEB.
Virtual net metering: residents of flats, residential complexes and residents’ association areas can share one plant through a lead person if it has storage of at least 20% of its generation potential. Low-income households identified by the local body can also join sponsored shared plants.

Common-area connections of apartment buildings and residential colonies can use net metering up to 500 kW, with storage needed above 25 kW.

How to apply

Register on pmsuryaghar.gov.in with your KSEB consumer number if you want the central subsidy, and pick a registered vendor. Our PM Surya Ghar guide has the steps.
Make sure your mobile number and email are registered with KSEB on its web self-service site (wss.kseb.in); KSEB’s solar rooftop portal requires them.
Apply online for feasibility. KSEB must acknowledge the application the same day and decide feasibility within 15 days; if it misses that on a complete application, feasibility is deemed granted. PM Surya Ghar plants up to 10 kW get deemed feasibility if the transformer has spare hosting capacity, the plant is within your connected load and the inverter rules are met.
Within 45 days of feasibility, apply for registration. KSEB scrutinises it within 3 working days and registers within 3 working days of a complete application and fee.
Install within six months of registration and submit the completion report. KSEB tests the system within 7 working days, signs the connectivity agreement within 7 working days of a successful test, and installs the meter and commissions the plant within 15 days of the report.

Fees are ₹1,000 for the application and ₹300 per kW for registration, both non-refundable. For PM Surya Ghar installations they are collected in your first bills after commissioning, and KSEB can waive them for subsidised schemes. The PM Surya Ghar national helpline is 15555.

Common pitfalls

Assuming a state top-up. Kerala households get the central subsidy only. Treat any extra “state subsidy” promised by a vendor with caution unless KSEB or ANERT has notified it.
Oversizing for export. Surplus is worth ₹2.79 a unit at year-end and less at night after normalisation, well below the tariff you avoid by using solar power yourself during the day.
Missing the April 2027 line. Plants above 5 kW that seek feasibility from 1 April 2027 need a hybrid inverter with storage and will pay grid support charges.
Ignoring transformer capacity. Feasibility is first come, first served per transformer. Where hosting capacity is exhausted, KSEB can still allow up to 20% more for small plants with qualifying hybrid inverters and storage.
Single-phase connections. Plants above 3 kW need three-phase inverters, so check your connection before you pick a size.
Paying agents to “register” you. Registration on the national portal is free.

Questions people ask

How much subsidy does a Kerala household get for rooftop solar?

The central PM Surya Ghar subsidy: ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, capped at ₹78,000 for systems of 3 kW and above. Kerala does not currently add a state cash top-up for homes, so the national portal figure is the whole subsidy.

Can I still get net metering in Kerala after the 2025 regulations?

Yes. Under the KSERC (Renewable Energy and Related Matters) Regulations, 2025, domestic consumers can opt for net metering from 1 kW to 20 kW, limited to their connected load. The draft had proposed limiting net metering to 3 kW, but the final regulations, notified on 5 November 2025, kept it up to 20 kW. Plants above 10 kW need a hybrid inverter with battery storage.

Do I have to install a battery?

Not for a typical home system today. Storage is required for domestic plants above 10 kW (at least 10% of the plant’s generation potential up to 15 kW, 20% above 15 kW up to 20 kW). For plants above 5 kW and up to 10 kW that seek feasibility from 1 April 2027, a hybrid inverter with at least 10% storage becomes mandatory. Systems of 5 kW and below have no storage requirement.

What is normalisation and does it affect me?

Since 1 January 2026, KSEB records exports and imports in three time zones: solar hours (8 am to 6 pm), peak (6 pm to 11.30 pm) and off-peak (11.30 pm to 8 am). Surplus exported after same-zone adjustment is banked, and when banked units are used against night-time imports they are scaled down: a domestic banked unit offsets 0.75 of a unit at peak and 0.85 off-peak. Plants up to and including 2 kW are exempt: their factor is 1 in every zone.

Do domestic prosumers pay grid support charges?

Not if the plant is 10 kW or smaller. Above that, the interim charge is 50 paise per unit for the first 300 units and ₹1 per unit after that, levied only on night-time grid use that is offset by banked energy. From 1 April 2027, new applicants for feasibility with plants above 5 kW will also have to pay it.

What happens to surplus units?

After paying for the fixed and other charges in each bill, leftover banked units carry forward, minus a 2% monthly banking charge, until the end of the financial year. Units still left are paid for at ₹2.79 a unit for new solar prosumers and ₹3.08 for existing ones, before 30 April. You can instead ask KSEB to carry the credit into the next year.

How long should approvals take?

The regulations set feasibility within 15 days of an online application, and feasibility is deemed granted if KSEB misses that deadline on a complete application. PM Surya Ghar systems up to 10 kW get deemed feasibility if the transformer has spare hosting capacity, the plant does not exceed your connected load and inverter rules are met. After registration, testing is due within 7 working days of your completion report and the meter within 15 days.

Sources

Net metering limits, storage rules, inverter and hosting-capacity rules, time zones, normalisation factors, banking charge, settlement rates, feed-in tariffs, grid support charges, fees and timelines are from the KSERC (Renewable Energy and Related Matters) Regulations, 2025, notified on 5 November 2025. The fixed-charge options are from KSERC’s order in OP 43 of 2025 as quoted in the Appellate Tribunal’s order of 16 February 2026. Installation figures are from the annexure to Lok Sabha unstarred question 2806, answered on 5 August 2026. Central rates are from the national portal.

Related reporting is on the solar and policy pages. Other state guides: Uttar Pradesh (a ₹15,000-per-kW top-up, up to ₹30,000), Rajasthan (₹17,000 and 150 free units), Maharashtra (the SMART scheme), Gujarat (central subsidy only), Tamil Nadu (up to ₹22,000) and Delhi (up to ₹78,000, with free plants for homes up to 400 units). If a number here disagrees with KSEB, KSERC or the national portal, theirs wins. Corrections: [email protected].