What a 600 kW Solar Plant Costs and Needs: Roof, Connection, Approvals

A 600 kW rooftop solar plant for a factory indicatively costs about ₹1.44 to 1.68 crore excluding GST (₹24,000 to 28,000 per kW, the lower end of our published band for larger plants). It needs roughly 60,000 sq.ft of shadow-free roof and generates about 72,000 units a month in north India. At 600 kW you are above the usual net-metering limit, so the metering route comes first.

What does a 600 kW plant cost, and what moves the number?

Our published band for commercial and industrial solar is ₹24,000 to 32,000 per kW excluding GST, with larger plants towards the lower end. Scaled to 600 kW and taking 24,000 to 28,000 per kW, that gives the range above. Treat it as indicative. Our 500 kW and 1 MW cost pages bracket this size, and the solar calculator lets you test your own bill.

Where you land in the range depends on a short list of site facts, not on module brand:

• Roof type and structure. Metal-shed roofing with clamp-on mounting is simpler than RCC with ballast or anchored structures, and a roof that needs strengthening adds cost.
• Number of roof blocks. Three or four sheds mean longer DC cable runs, more combiner points and more walkway and safety provision than one large roof.
• Interconnection voltage and works. A tie-in at the factory's existing HT supply may need protection, metering, a breaker or a bay, and a transformer loading check.
• Inverter architecture and monitoring. The choice between string and central inverters changes both price and serviceability.
• Approvals and meter scope. Net, gross or captive metering changes the equipment and the paperwork.

How much roof does it need and what will it generate?

The planning allowance is about 100 sq.ft of shadow-free roof per kW, which the Ministry of New and Renewable Energy's rooftop programme puts at about 10 sq. m per kW. For 600 kW that is about 60,000 sq.ft, and usable area is usually lower than the paper area once skylights, vents, parapets and rooftop equipment cast shadows. A shadow study before design converts the paper area into the real one, and the solar plant area calculator gives a first estimate.

Generation depends on location. A planning figure for north India is about 120 units per kW per month, so 600 kW yields about 72,000 units a month, or about 8.6 lakh units a year, with summers above and the winter fog months below. Rajasthan and Gujarat run higher, and the East and North East lower. Whether you can use all of it depends on your daytime load, a point we return to under metering.

Why 600 kW is above most net-metering limits

The Ministry of Power's year-end review records that the Electricity (Rights of Consumers) Rules were amended on 29 September 2021 to raise the net-metering limit from 10 kW to 500 kW. The regulations of each state commission fix the details, including how the cap relates to your sanctioned load and what happens above it. Our own 1 MW page notes, for example, that Punjab's current rule allows up to 100% of sanctioned load within a 500 kWp net-metering limit.

For 600 kW, that means asking your DISCOM which of these applies to you, before the layout is drawn. If the cap is 500 kW you can split the decision: size the plant to the cap, or route the whole 600 kW through a different arrangement.

Each route has different charges and approvals. Open access for green energy is allowed from 100 kW of contract demand under the Green Energy Open Access Rules, 2022, with approval due in 15 days or deemed granted, according to the Ministry of Power's release. Captive status is a separate legal test (the users must hold at least 26% of ownership and consume at least 51% of the electricity annually, under Rule 3 of the Electricity Rules, 2005).

Inverters, voltage and the DISCOM connection

At 600 kW the plant is a small power station inside a working factory. Two design choices matter early. First, the interconnection voltage: whether the plant ties in at 415 V on the LT side of an existing transformer or at 11 kV or higher on the HT side depends on the transformer's capacity and loading, the DISCOM's rules and the layout. Second, the inverter architecture: string inverters (typically 10 to 12 units of 50 to 60 kW for this size) give fault tolerance, since one failed unit costs a tenth of generation; central inverters reduce the unit count but concentrate risk. See the glossary entry on string versus central inverters.

Check DG interlocks as well. A plant that back-feeds a DG set during an outage damages equipment, so the changeover logic belongs in the scope.

Approvals and a realistic programme

The usual sequence is: site survey and shadow study; DISCOM feasibility and connection application; design and single-line diagram; electrical inspector (CEIG) approval of the drawings where the installation requires it; procurement; installation; inspection; DISCOM synchronisation and meter change; commissioning. Our guide to CEIG approval for factories explains the inspector's role.

As a planning allowance, assume roughly five to eight months from order to commissioning, and test it against your DISCOM's own timelines, because approvals rarely run to the contractor's calendar. That matters this year. As of October 2026, the Ministry of New and Renewable Energy's O.M. of 4 August 2026 exempts net-metering and open-access projects from the ALMM List-II (solar cells) requirement only if they are commissioned by 31 December 2026; List-I (modules) still applies. The same O.M. states that ALMM does not apply to behind-the-meter plants used solely for captive consumption by a consumer other than a government entity or public sector enterprise. Read the O.M. and see our glossary note on ALMM; your route decides which regime you are in.

How Secured Engineers helps

We design in-house and file Fire NOC, CEIG and DISCOM net-metering applications in-house, so the metering decision, the single-line diagram and the approvals are handled by one team. MEPF and solar can sit under one contract. We work from offices in Noida (Delhi NCR) and Ludhiana, with 535+ projects across 18+ states and 89.77% repeat clients. Each plant is priced after a survey; the figures in this article are indicative only.

To size a plant against your bill, start with the solar calculator and then check the numbers with the payback calculator. Send us a recent bill, message us on WhatsApp, call +91 70099 85817, or ask for a free proposal.