Ambattur Industrial Estate is one of Chennai's oldest and busiest manufacturing hubs, with more than 1,500 units making auto components, engineering products, garments and more since 1964. Most of these units run daytime shifts on industrial tariffs of ₹7.50–8.25 a unit, which makes rooftop solar one of the fastest-paying investments an Ambattur factory can make. This guide explains how a solar EPC project works for a unit in Ambattur, and what to plan for that is specific to the estate.
Why rooftop solar suits Ambattur Industrial Estate
- Daytime load: most units run day shifts, so solar power is used on site as it is generated, which gives the best return.
- High tariffs: LT industrial (LT IIIB) consumers pay about ₹8.25 a unit and HT industrial consumers about ₹7.50 a unit, plus a 25% peak-hour surcharge for HT in the morning peak (6–10 am).
- Large flat roofs: factory sheds and RCC buildings offer shade-free roof area that is otherwise unused.
- Tax benefit: a profitable company that owns its plant can claim 40% accelerated depreciation, which shortens the real payback.
- Customer pressure: auto OEMs and export buyers increasingly ask suppliers about renewable energy use and emissions. Solar gives Ambattur suppliers a measurable answer.
Industries in Ambattur and how they use solar
| Industry | Main loads | Solar fit |
|---|---|---|
| Auto components | CNC and VMC machines, compressors, heat treatment | Excellent. Steady daytime machining load |
| Engineering and fabrication | Welding, cutting, press machines, compressors | Very good. Size to base load, as welding loads fluctuate |
| Garments and textiles | Sewing machines, steam pressing, lighting, fans and AC | Very good. Long daytime shifts with large roofs |
| Plastics and moulding | Injection moulding machines, chillers | Good. High load; solar covers part of it |
| Food processing and packaging | Ovens, refrigeration, packing lines | Good. Refrigeration runs through the day |
| Printing and electronics | Presses, SMT lines, air conditioning | Good. Daytime operation with cooling loads |
For more on sizing to shifts and load, see our guide to solar for factories in Chennai.
Roof types in Ambattur and how solar is mounted on them
Ambattur has a mix of older SIDCO-built sheds and newer buildings, so roof type varies widely from unit to unit. Mounting is one of the most important parts of the EPC design.
Whatever the roof, ask your EPC company for a structural assessment and wind-load design in writing. Our guide on solar in Chennai's monsoon and cyclones explains what a cyclone-rated design should include.
How big a solar plant fits your shed?
Many Ambattur units are compact, so roof area often sets the plant size before your load does. As a rough guide, 1 kW needs about 80–100 sq ft of shade-free roof on metal sheets and about 100–120 sq ft on RCC with elevated structures.
| Usable shade-free roof | Approximate plant size | Annual generation |
|---|---|---|
| 2,500 sq ft | 20–30 kW | 29,000–43,500 units |
| 5,000 sq ft | 40–60 kW | 58,000–87,000 units |
| 10,000 sq ft | 80–120 kW | 1.16–1.74 lakh units |
| 25,000 sq ft | 200–300 kW | 2.9–4.35 lakh units |
Generation is based on about 1,450 units per kW per year in Chennai. The ideal size is the smaller of what your roof can hold and what your daytime load can use, because surplus exported to the grid earns a much lower rate.
Solar plant cost, savings and payback for Ambattur factories
| Plant size | Approximate cost | Units per year | Annual saving at ₹8.25 | Simple payback |
|---|---|---|---|---|
| 25 kW | ₹9–12.5 lakh | ~36,250 | ~₹3 lakh | 3–4 years |
| 50 kW | ₹15–25 lakh | ~72,500 | ~₹6 lakh | 2.5–4 years |
| 100 kW | ₹30–50 lakh | ~1,45,000 | ~₹12 lakh | 2.5–4 years |
| 250 kW | ₹75 lakh–1.25 crore | ~3,62,500 | ~₹30 lakh | 2.5–4 years |
Savings are year-one estimates for LT industrial consumers, assuming all solar power is used on site, before panel degradation and any applicable network charges. HT consumers save on their energy charge of about ₹7.50 a unit, but demand charges do not change. For a detailed breakdown, see commercial & industrial solar in Chennai: cost, ROI and process.
The solar EPC process for an Ambattur unit
Review of 12 months of TNPDCL bills, sanctioned load, shift timings and major machines to find your daytime base load.
Roof type, sheet and purlin condition, shading from neighbouring sheds, water tanks and chimneys, and space for inverters and cabling.
Plant size, layout, single-line diagram, generation estimate and an itemised quote with named panel, inverter and structure makes.
TNPDCL application and, for larger plants, Electrical Inspectorate approval, plus the metering arrangement for your consumer category.
Structure, panels, inverters and protection installed, with work planned around your shifts and electrical tie-in scheduled on a holiday to avoid production loss.
Testing, inspection, meter installation and handover, followed by cleaning, monitoring and preventive maintenance.
Things to plan for that are specific to Ambattur
- Dust and soot: panels in a busy industrial estate collect dust from traffic, machining and neighbouring chimneys faster than residential roofs. Plan for more frequent cleaning, typically every one to two weeks, and an easy water point on the roof.
- Waterlogging: parts of Ambattur have seen waterlogging in heavy monsoons. Mount inverters, ACDBs and DCDBs well above ground level, ideally on the roof or a raised wall.
- Shading from neighbours: sheds are close together, so check shading from taller buildings, water tanks and chimneys, including any planned construction next door.
- Leased or allotted sheds: if you lease your premises or the shed is allotted, get written consent from the owner or allotting authority before signing, and make sure your lease covers the payback period.
- Old electrical panels: many older units have aged LT panels. Your EPC company should check the main panel, earthing and protection, and include upgrades in the quote if needed.
Funding options for MSMEs in Ambattur
- Outright purchase (CAPEX): the highest lifetime savings, plus 40% accelerated depreciation if you have taxable profit.
- Loan-funded purchase: MSME and solar loans let the monthly saving cover most or all of the EMI. See solar loans in Chennai.
- Zero-investment (RESCO / OPEX): a developer installs and owns the plant and you pay a lower per-unit rate. It usually needs about 100 kW or more. See zero-investment solar for factories in Chennai.
To compare contractors and bids, read our guides to solar EPC contractors for factories and the top solar EPC companies in Chennai.
Frequently asked questions
How much does a solar plant cost for a factory in Ambattur?
About ₹30,000–50,000 per kW in 2026, depending on size, roof type and equipment. A 50 kW plant costs roughly ₹15–25 lakh and a 100 kW plant roughly ₹30–50 lakh.
What is the payback period for solar in Ambattur Industrial Estate?
Typically about 3–4 years for an LT industrial unit that uses most of its solar power during daytime shifts, and shorter if you claim accelerated depreciation.
Can solar be installed on a metal sheet roof?
Yes. Panels are mounted with clamps designed for the sheet profile and sealed fixings. The sheet and purlins should be checked first, and the roof should have enough remaining life to carry the plant for its full lifetime.
Can solar be installed on an asbestos sheet roof?
Asbestos-cement sheets should not be drilled or walked on. The usual options are an independent steel structure above the roof or replacing the roof with metal sheets before installing solar.
How big a solar plant can I fit on my shed?
Roughly 1 kW per 80–100 sq ft of shade-free metal roof, or 100–120 sq ft on RCC. A 5,000 sq ft roof can typically hold about 40–60 kW.
Will installation stop production?
No. Most work happens on the roof during normal operations. The electrical connection to your main panel is usually scheduled on a holiday or during a planned shutdown.
Do you serve units near Ambattur?
Yes. Arka Solar Energy serves Ambattur Industrial Estate and nearby areas, including Padi, Mogappair, Pattaravakkam, Korattur and Thirumullaivoyal, from our Chennai office.
Running a unit in Ambattur Industrial Estate?
Arka Solar Energy is a solar EPC company in Chennai. Share your electricity bills and roof details, and we'll visit your unit and send a design, generation estimate and payback model.
Costs, tariffs and savings are indicative as of October 2026 and vary by site, plant size, equipment and tariff category. Tamil Nadu tariffs and charges are set by TNERC and may change. Consult your chartered accountant on depreciation and tax treatment.