Choosing a solar EPC contractor for a factory is not like buying a home system. You are handing a contractor your roof, your electrical panel and part of your production schedule, and committing to a plant that must perform for 25 years. The right partner depends on whether you want to own the plant, buy power without investing, or source solar from off-site. This guide covers the main contractors serving Chennai's industrial belts and how to compare them.
Three kinds of solar partner for factories
| Partner type | What they do | You pay | Best for |
|---|---|---|---|
| EPC contractor | Designs, supplies, installs and maintains a plant that you own | Upfront (CAPEX) or via a loan | Profitable factories wanting the highest lifetime savings and accelerated depreciation |
| C&I developer (RESCO / OPEX) | Builds and owns the plant on your roof and sells you the power per unit | A per-unit tariff, typically below your grid rate, over a long contract | Factories that want zero upfront investment |
| Off-site / group captive provider | Supplies solar from a remote plant through the grid | Per-unit tariff plus grid charges | Large HT consumers with limited roof space |
Many companies offer more than one model. Decide your preferred model first; it narrows the shortlist quickly. For costs and ROI under each model, see commercial & industrial solar in Chennai: cost, ROI and process.
Solar EPC contractors and C&I developers serving Chennai factories
Arka Solar Energy
A Chennai-based industrial and commercial solar EPC company handling energy audits, engineering, supply, installation, TNPDCL approvals, commissioning and O&M with one in-house team. Arka designs cyclone-rated, hot-dip galvanised structures for Chennai's wind zone, including mounting systems for metal-sheet factory roofs, and helps clients compare CAPEX, loan and RESCO options.
- 200+ installations and 2 MW installed, as stated on its website
- Serves Ambattur, Guindy, Sriperumbudur, Oragadam, Irungattukottai, Maraimalai Nagar and Gummidipoondi
- Free energy audit with a site-specific design and ROI model
Best for: factories and MSMEs wanting to own their plant with a local, accountable EPC team.
SWELECT Energy Systems
A Chennai-headquartered renewable energy company (formerly Numeric Power Systems) citing 41+ years in power and energy. It offers rooftop solar for commercial and industrial customers, an EPC division covering design to commissioning, and energy sales to C&I consumers. Its subsidiary operates a module manufacturing facility in Coimbatore producing mono PERC and TOPCon modules.
Best for: buyers who value a long-established Chennai company with in-house module manufacturing.
CleanMax
One of India's large C&I renewable developers, offering onsite and offsite solar to businesses, and credited with popularising the OPEX model in Indian C&I solar. It has commissioned group captive projects in Tamil Nadu since 2017.
Best for: large factories wanting OPEX or group captive supply with no upfront investment.
Fourth Partner Energy
A distributed-energy company offering on-site rooftop, ground-mount and carport solar, off-site open access solar and wind, hybrid projects and battery storage. It cites over 3,000 projects executed across distributed solar and open access.
Best for: multi-site manufacturers wanting rooftop plus open access from one provider.
Tata Power Solar
Offers commercial and industrial rooftop and ground-mounted solar backed by the Tata Power Group, alongside its residential business.
Best for: companies whose procurement policy favours a large national brand.
Kondaas Automation
A Tamil Nadu solar company offering commercial solar for offices, factories and warehouses, highlighting accelerated depreciation and net metering, as well as larger solar park projects. Chennai is among its listed service locations.
Best for: factories wanting a long-standing Tamil Nadu company, especially with sites in western Tamil Nadu too.
AMPIN Energy Transition (formerly Amplus Solar)
Focuses on large rooftop and open-access renewable supply for businesses, rather than smaller installations.
Best for: large energy users planning rooftop plus off-site supply.
Waaree Renewable Technologies
Handles commercial and industrial rooftop and ground-mounted EPC, backed by the Waaree group's large module manufacturing base.
Best for: buyers who want manufacturer-led EPC.
For a broader comparison including homes and smaller businesses, see the top solar EPC companies in Chennai and the top 10 solar companies in Chennai.
How to evaluate a solar EPC contractor: the scorecard
Score each shortlisted contractor from 1 to 5 on these points. The brand matters far less than the answers.
| Criterion | What a strong answer looks like |
|---|---|
| Industrial track record | Completed plants of similar size and roof type, with references you can call and visit |
| Design quality | Site-specific generation simulation, shading analysis, string and inverter design, single-line diagram |
| Structural engineering | Roof and purlin assessment, wind design for Chennai's 50 m/s zone (IS 875 Part 3), galvanised structure |
| Equipment transparency | Panel, inverter, structure and cable brands named in the contract, not "Tier-1 equivalent" |
| Performance guarantee | A written generation or performance-ratio guarantee, with how it is measured and compensated |
| Approvals capability | Experience with TNPDCL applications, Electrical Inspectorate approval and HT metering |
| Safety | Working-at-height procedures, permits, lifelines, insured workforce, safety officer on site |
| O&M terms | Cleaning schedule, preventive maintenance, response time for faults, monitoring access |
| Local presence | A team in Chennai that can reach your site quickly |
| Financial strength | Able to stand behind workmanship warranties for years |
What to send contractors for an accurate bid
Vague enquiries get vague quotes. Share these to get bids you can compare:
- 12 months of electricity bills showing tariff category (HT or LT), contract demand and consumption
- Load profile: shift timings, weekday vs weekend operation, and any seasonal shutdowns
- Roof details: drawings or photos, roof type (metal sheet or RCC), age and condition of sheets, available area
- Electrical details: single-line diagram, transformer and LT panel details, available space for inverters
- Your preferred model: CAPEX, loan, RESCO or open to comparison
- Constraints: safety rules, working hours, access restrictions, insurance requirements
How to compare solar EPC bids like for like
| Compare | Why it matters |
|---|---|
| Cost per kWp (DC) and total price | Check whether DC or AC capacity is quoted; they are not the same |
| Guaranteed first-year generation | The real measure of value: ₹ per unit generated over the plant's life |
| Panel and inverter make and model | Determines efficiency, degradation and warranty strength |
| Structure specification | Galvanising thickness, height, wind rating, roof attachment method |
| Scope inclusions | Approvals, metering, civil work, cable runs, monitoring, insurance during construction |
| Warranties | Panel product and performance, inverter, and workmanship years |
| O&M cost and scope | Free O&M period, then the yearly cost and what it covers |
| Payment milestones | Linked to delivery, installation and commissioning, not mostly upfront |
| Timeline | Realistic schedule including approvals |
The cheapest per-kWp bid is often the most expensive per unit generated. Always compare the guaranteed generation alongside the price.
Factory-specific issues to get right
- Size to daytime load, not roof size. Solar saves most when it is used on site. If you run one shift or close on Sundays, oversizing can push surplus into export, which earns far less than the power you avoid buying.
- Know what solar won't cut. Solar reduces the energy charge, but not the HT demand charge, which depends on your maximum demand. A credible proposal says so.
- Check the roof before the solar. Old or corroded metal sheets should be replaced or repaired first; removing a plant later to re-roof is costly.
- Plan installation around production. Good contractors phase work and schedule shutdowns for electrical tie-ins.
- Make safety a contract term. Roof work is high-risk; insist on permits, lifelines and insurance.
- Plan for the monsoon. Cyclone-rated design matters in Chennai. See solar in Chennai's monsoon and cyclones.
- Understand the metering rules. HT and LT connections are treated differently under TNERC rules. See TANGEDCO solar rules and regulations.
Red flags when hiring a solar EPC contractor
- No site visit or structural check before quoting
- Generic "Tier-1 equivalent" equipment instead of named makes and models
- No written generation or performance guarantee
- Most of the payment demanded before material delivery
- Savings that ignore your actual load profile or the demand charge
- No references from similar industrial projects
- Vague answers on who handles TNPDCL and Electrical Inspectorate approvals
Frequently asked questions
Who are the top solar EPC contractors for factories in Chennai?
Options include Chennai-based EPC contractors such as Arka Solar Energy and SWELECT Energy Systems, C&I developers such as CleanMax, Fourth Partner Energy and AMPIN, and national or manufacturer-led EPC players such as Tata Power Solar and Waaree Renewable Technologies. The right choice depends on whether you want to own the plant or buy power.
What is the difference between an EPC contractor and a RESCO developer?
An EPC contractor builds a plant that you own and pay for upfront or through a loan. A RESCO developer builds and owns the plant on your roof and sells you the power per unit, so you invest nothing upfront but save less over the plant's life.
How do I compare solar EPC quotes for my factory?
Compare the price per kWp alongside the guaranteed generation, equipment makes, structure specification, scope inclusions, warranties, O&M terms and payment milestones. The cheapest per-kWp quote is often not the cheapest per unit generated.
What information should I give a solar contractor for a quote?
Twelve months of electricity bills, your load profile and shift timings, roof drawings or photos with roof type and condition, your single-line diagram and panel details, and whether you prefer CAPEX, loan or RESCO.
How much does a factory solar plant cost in Chennai?
Roughly ₹30,000–50,000 per kW in 2026, so about ₹30–50 lakh for 100 kW, with lower per-kW costs for larger plants. Payback is typically about 2.5–4 years when most power is used on site.
Can solar be installed without stopping factory production?
Mostly yes. Structure and panel installation can run alongside production; only the electrical tie-in usually needs a short planned shutdown, which a good contractor schedules with you.
Does solar reduce the HT demand charge?
Not significantly. Solar mainly reduces the energy charge. The demand charge depends on your maximum demand, which usually occurs when solar output is low or loads peak.
Get a factory solar proposal
Arka Solar Energy, a Chennai-based industrial solar EPC company, will review your bills and roof and send a plant design, generation estimate and ROI model, with CAPEX, loan and RESCO compared.
Company information is summarised from public sources and company websites as of October 2026 and may change. Inclusion does not imply endorsement by or partnership with any company listed. Confirm current services and coverage directly.