Solar FAQs: Cost, Subsidy & TNEB Approval | VENAARC

Question 1

How does the PM Surya Ghar subsidy work, and am I eligible?

Accepted Answer

PM Surya Ghar Muft Bijli Yojana is a central government scheme for residential rooftop solar. Under the scheme as it currently stands, the subsidy is ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, which caps the residential benefit at ₹78,000 for a 3 kW or larger system. It applies to residential electricity connections only - not to commercial, industrial or agricultural ones. You register on the National Portal (pmsuryaghar.gov.in) with your TANGEDCO consumer number, get feasibility approval, have the system installed by a registered vendor, and the subsidy is credited to your bank account after net metering and inspection are complete. Amounts, eligibility and the scheme itself are decided by the government and can change; everything here is indicative and subject to eligibility under the scheme rules in force when you apply. VENAARC prepares and files the paperwork and follows it up with you.

Question 2

Can a housing society or apartment building get solar and a subsidy?

Accepted Answer

Yes, and it is one of the most cost-effective things a society can do. The usual approach is a system on the terrace feeding the common-area connection - lifts, motors, corridor and parking lighting, the water pump - which cuts the maintenance bill every flat pays into. PM Surya Ghar also has a separate provision for group housing societies and residential welfare associations covering common facilities, at a lower per-kW rate than the individual residential slabs and subject to its own cap and eligibility rules. Individual flats with their own connections may also apply on their own if they have exclusive rights to roof space. Societies need a resolution and a decision on how the roof and the savings are shared, so start that conversation early - we can help you put the technical and commercial case to the members.

Question 3

How does TNEB net metering work and how long does approval take?

Accepted Answer

Net metering lets you export the solar power you do not use into the TANGEDCO grid and draw it back later, so your bill is settled on net consumption. The sequence is: apply to your TANGEDCO section office (with the scheme application, if you are claiming subsidy), receive technical feasibility approval, install and commission the system, then have the installation inspected and a bidirectional meter fitted before the arrangement goes live. Timelines are genuinely variable - they depend on your section office, transformer capacity in your area and how complete the file is - so we will not quote you a number we cannot control. What we can promise is that we prepare the application, attend the inspection and chase the file, and that we tell you honestly where it stands.

Question 4

Will my sanctioned load or connection type limit my system size?

Accepted Answer

Yes, and it is worth checking before you fix a system size. Rooftop solar capacity is normally allowed up to the sanctioned load of your service connection, and the distribution transformer feeding your street has to have headroom for the export. If the system you want is larger than your sanctioned load, you may need to enhance the load first. Whether your connection is LT (most homes and small businesses) or HT (larger commercial and industrial) also changes the applicable regulations and tariff treatment. We check all of this during the site survey rather than after the panels arrive.

Question 5

What does rooftop solar cost per kW in Tamil Nadu?

Accepted Answer

As an indicative range, a grid-tied residential rooftop system usually works out to roughly ₹45,000 to ₹75,000 per kW installed before subsidy, and smaller systems cost more per kW than larger ones because the fixed costs of structure, cabling and approvals are spread over less capacity. Hybrid systems with battery storage cost significantly more, because batteries are the single most expensive component. Where you land inside that range depends on module and inverter brand, roof type and height, how far the inverter sits from your meter, and whether the structure has to be elevated or wind-rated. These are planning numbers, not a quotation - a firm price comes only after a site survey.

Question 6

How much will I actually generate, and how much will I save?

Accepted Answer

Tamil Nadu has good solar resource. A well-sited, shadow-free rooftop system here typically generates in the region of 4 to 4.5 units per kW per day averaged over the year - roughly 1,400 to 1,600 units per kW annually - which is an indicative planning figure, not a guarantee. What that saves you depends on your TANGEDCO tariff slab: because domestic tariffs are slab-based, solar saves the most for households whose consumption pushes them into the higher slabs. The honest way to size a system is to work backwards from twelve months of your actual bills, which is exactly what we do at the survey.

Question 7

What payback can a commercial or industrial rooftop expect?

Accepted Answer

For a commercial or industrial consumer paying HT or LT commercial tariffs, payback is usually faster than for a home, because the tariff you are displacing is higher and the load runs during daylight hours. An indicative range is around 4 to 6 years, with the system expected to keep producing for decades after that. Businesses can also claim accelerated depreciation on the asset under the Income Tax Act, which improves the post-tax numbers - your auditor should confirm how that applies to you. Open Access and Group Captive structures change the economics again for larger loads. Every one of these figures is indicative until we have modelled your actual load profile and tariff.

Question 8

How much roof area do I need per kW?

Accepted Answer

As a rule of thumb, allow about 80 to 100 square feet of shadow-free roof per kW for a standard fixed-tilt rooftop installation - so a 3 kW home system wants roughly 250 to 300 square feet. Elevated structures that keep the roof usable underneath, or carport-style mounting, need more spacing. What matters more than the raw area is that it is genuinely shadow-free between about 9 am and 4 pm: a water tank, a parapet wall, a neighbouring building or a coconut tree can cost you more generation than people expect, because shade on one part of a string affects more than just that panel. We do a shadow study as part of the survey.

Question 9

On-grid, off-grid or hybrid - which one do I need?

Accepted Answer

On-grid (grid-tied) is the default and the cheapest: no batteries, it exports surplus to TANGEDCO under net metering, and it shuts down during a power cut for the safety of line staff. Hybrid adds a battery, so selected circuits keep running during an outage while you still get net-metering benefit on the rest - this is what most Tamil Nadu homes with frequent outages actually want, and the cost depends on how much backup you ask for. Off-grid means no grid connection at all, with the battery bank sized for your worst case; it makes sense for remote sites, farm pumps and installations where there is simply no reliable supply, but it is the most expensive per unit. If your goal is a lower bill, on-grid. If it is a lower bill plus backup, hybrid.

Question 10

What happens during the monsoon and on cloudy days?

Accepted Answer

Output drops but does not stop - panels still generate from diffuse light on an overcast day, typically a fraction of a clear-sky day rather than zero. Tamil Nadu gets most of its rain from the northeast monsoon between October and December, and generation in those weeks is visibly lower. This is why systems are sized on annual generation rather than a good day: the strong months either side of the monsoon carry the average, and net metering banks your surplus so a sunny March helps pay for a wet November. Rain also washes the panels, which is the one thing the monsoon does for you.

Question 11

How much maintenance does a solar system need?

Accepted Answer

Very little, but not none. A photovoltaic system has no moving parts; the maintenance is mostly keeping the glass clean and the electricals healthy. In dusty locations, near a main road, or during the dry pre-monsoon months, panels benefit from a rinse every two to four weeks - dust, bird droppings and pollen can measurably cut output. Beyond that: an annual electrical check of connections, earthing and the inverter, a look at the mounting structure for corrosion and loose clamps, and keeping an eye on the monitoring app so a dip in generation gets noticed early rather than at the end of the year. VENAARC offers scheduled operations and maintenance contracts if you would rather not think about any of it.

Question 12

How do the warranties actually work?

Accepted Answer

There are three separate things, and it helps to keep them apart. First, the module warranty from the panel manufacturer: usually a product warranty against defects for around 10 to 12 years, plus a much longer performance warranty - commonly 25 years - promising the panel still produces above a stated percentage of its rated output. Second, the inverter warranty from the inverter manufacturer, typically around 5 to 10 years with an option to extend; the inverter is the component most likely to need replacing within the system life. Third, our workmanship warranty on the installation, structure and cabling, for the period stated in your contract. The first two are the manufacturers’, on their terms - we hand over the documents and we raise and pursue any claim on your behalf.

Question 13

What does the whole process look like, start to finish?

Accepted Answer

Roughly this. (1) You send an enquiry and we talk through your bills, your roof and what you want out of the system. (2) Site survey: measurements, shadow study, roof and structural condition, where the inverter and cabling will run, and a look at your sanctioned load. (3) A written proposal with the system design, a firm price and an honest generation estimate. (4) On acceptance, we file the TANGEDCO net-metering application and the PM Surya Ghar registration where applicable. (5) Installation, which for a typical home system is a matter of days on site once material is delivered. (6) Inspection, bidirectional meter and commissioning. (7) Handover with documents, warranty papers and monitoring access, followed by subsidy disbursement if you are claiming it. (8) Ongoing support and optional maintenance. Nothing binding is quoted before step 3.

Question 14

How long does installation itself take?

Accepted Answer

The physical installation is the fast part. A typical residential rooftop system is usually a few days of work on site once the design is signed off and material has arrived. Commercial and industrial rooftops run from a few weeks to a couple of months depending on capacity, structural work and how much of it has to be done around your operations. The calendar time from enquiry to a live, net-metered system is usually driven by approvals rather than by construction, which is why we start the paperwork in parallel rather than after.

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