Solar O&M Contract for a 1 MW Rooftop Plant: Scope, SLAs and What It Should Cost

A 1 MW rooftop O&M contract should fix five things: a cleaning calendar with the water source, preventive and thermography checks, inverter response and restoration times, monitoring with a monthly performance ratio report, and who pays for spares. As a reference point, Karnataka's 2026 regulator tariff norm puts plant O&M at 1% of capital cost a year; real contracts move with scope.

What should the scope cover?

At 1 MW you have roughly 1,800 modules if they are 550 W each, several inverters and many string connections. The contract has to say who looks at which part, how often, and what evidence you receive. Use this table as a checklist when you compare bids.

The owner of an electrical installation stays responsible for keeping it safe under the CEA safety regulations, whoever maintains it, so the contract should record the tests that prove it. Our CEIG guide explains the inspector's role.

Which SLAs matter, and how should they be written?

A service level agreement is only as good as its definitions. These are the ones to pin down.

• Response time: hours from a logged ticket to a qualified person acting, with shorter times for a full-plant outage than for a single string.
• Restoration time: hours to bring the plant back, with the spares condition stated. A fast response with no spares is only a visit.
• Availability: the share of daylight hours in which the plant is able to generate, with grid outages and your own shutdowns excluded by name.
• Performance ratio: the floor the contractor commits to, how it is measured and who owns the data.
• Remedy: service credits, a retained amount or termination rights if a service level is missed for a stated period.

One workable structure is to rank faults by priority and give each rank its own times. Fill the brackets with figures that suit your plant and your tolerance for lost generation; there is no standard value.

Performance ratio is plant output compared with what the measured irradiance should produce. The 2015 SECI tender for rooftop plants on CPWD buildings defined it as measured output divided by installed capacity, multiplied by 1,000 W per square metre over the measured irradiance. That scheme asked for at least 75% at commissioning acceptance, and a capacity utilisation factor of at least 15% maintained for five years. These are old, scheme-specific figures, not a standard. Set your own floor from the commissioning test of your own plant, and measure irradiance with a calibrated sensor in the plane of the modules. The same relationship underlies IEC 61724-1, the standard for PV system monitoring.

Performance ratio corrects for sunshine, so a cloudy month does not look like a failure. Capacity utilisation factor does not, so use it for annual yield and PR for contract performance. KERC's generic tariff assumes 19% capacity utilisation, which on 1 MW gives about 1.66 million units a year as a planning figure, not a yield promise.

What should it cost?

There is no regulated price for a private O&M contract. The reference point is the cost norm that KERC uses in its generic rooftop tariff: operation and maintenance equal to 1% of capital cost, escalated at 5.72% a year. Applied to the published C&I band of ₹24,000–32,000 per kW excluding GST on our solar EPC page, a 1 MW plant costs ₹2.4–3.2 crore, and 1% of that is ₹2.4–3.2 lakh a year. This is arithmetic on a regulator's assumption, not a Secured Engineers price.

A real contract can sit above or below that figure. What moves it:

• Soiling and water: a dusty site needs more cleaning rounds, and purchased water or tankers add cost.
• Roof access: height, fragile sheets and production hours slow every visit.
• Comprehensive or non-comprehensive: whether parts, and inverter replacement, are included or billed separately.
• Monitoring depth: string-level data and thermography cost more than a daily inverter log.
• Distance from the contractor's service base, which drives response time.

The solar AMC cost calculator shows how the cost changes with coverage level. For a plant whose EPC warranty is still running, ask what the O&M contractor will do differently from the warranty provider, so you do not pay twice for the same obligation.

How do you keep the contract honest?

Ask for the monthly report in a fixed format and compare it with your own meter. Ask for raw data export so you can change contractors without losing the plant's history. Make the contractor record roof leaks and damage found on visits, since a rooftop plant sits on a production asset. Put a handover clause in the contract, so that a successor receives logs, drawings, spares and passwords. Review the performance ratio trend every quarter, not only when a bill looks wrong.

How Secured Engineers helps

We design the plant in-house and file the DISCOM net-metering and CEIG papers ourselves, so the commissioning baseline that an O&M contract measures against is one we have recorded. 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. Our solar O&M and performance service covers cleaning, preventive checks, thermography and PR reporting.

If you have an O&M quotation for a 1 MW plant, send it with the generation data and we will tell you what is missing. You can also message us on WhatsApp, call +91 70099 85817, or ask for a free proposal on a new solar plant.