Solar for Dairy Plants: Sizing, Roof, Approvals and Payback (50 kW+)

A dairy plant sizes solar from its daytime load, not its total bill. Pasteurising, processing, packing and cold-room hours line up with the sun; early-morning milk reception and chilling, and night-time refrigeration, do not. Size the plant to the daytime base load within your sanctioned load, check the transformer, and net-meter up to 500 kW or go captive above it.

How does a dairy plant's load line up with the sun?

A dairy's electrical load is not flat. Milk arrives in the early morning and evening, chilling starts at once, processing and pasteurisation run through the day, and refrigeration keeps running at night. Solar generation runs roughly from eight in the morning to five in the evening, peaking near noon. So part of the load is served by the plant and part never will be unless you add storage. The table is a reading guide for your own meter data, not a measurement.

Pull twelve months of bills and, if you have a smart meter, the half-hourly profile. The daytime base load, the minimum load you carry between about nine and four, is the number that caps a sensible plant, because generation above it is exported. Seasons matter in a dairy, since flush-season volumes and summer cooling load shift the daytime base.

How do you size the plant from the bill?

1. Find the sanctioned load or contract demand. A net-metered plant cannot exceed it.
2. Find the daytime base load from the meter profile or from the shift pattern and the connected equipment.
3. Choose a plant whose peak output sits at or below that base load, so that nearly every unit is used on site.
4. Check the roof or yard against the plant: about 100 square feet of shadow-free roof per kW, or the ground area for a yard array (3.5 to 5 acres per MW on our size pages).
5. Check the transformer that serves you, because the DISCOM tests feeder and transformer headroom before it approves the plant.

For scale, our size pages put 100 kW at about 12,000 units a month, 250 kW at about 30,000, 500 kW at about 60,000 and 1 MW at about 1.2 lakh, at about 120 units per kW per month in north India. The sanctioned load calculator tests the size limit and the solar calculator turns a bill into a plant size. Our guide to sizing solar against a factory bill shows the line-by-line reading.

Roof, shed or yard?

Dairy buildings are often insulated sheds with condensers, vents and stacks on the roof, wash-down areas below, and a wet, cleaned-daily environment. A roof plant has to route around those. It also inherits the roof's condition: ask for a structural check, and for waterproofing at every penetration, because a leak into a food-processing hall is a hygiene problem and not only a repair. Our guides on roof structural loading and roof penetration and waterproofing cover both.

Many dairy plants have open yard or spare land. A ground-mounted array avoids the roof, is easier to clean, and fits above 500 kW where roofs run out; it adds foundations, a boundary and a cable run to the HT yard. We have no separate ground-mount price, so ask for those lines itemised. Our guide to ground-mount solar on factory land sets out the land checks. Keep arrays clear of effluent areas and tanks, and ask for corrosion-resistant coatings and cable protection where washdown chemicals or process vapours reach the structure.

Which approval route applies?

The Ministry of Power's 2021 amendment raised the net-metering limit to 500 kW, and states set the details and their own ceilings. A dairy up to that size, within its sanctioned load, is a net-metering case with the DISCOM. Above that, the choices are a behind-the-meter captive plant, a captive or group captive plant through open access, or a third-party supply. The Green Energy Open Access Rules, 2022 lowered the open-access threshold for green energy from 1 MW to 100 kW and provide for approval in 15 days or deemed approval. Our open-access solar page sets out the charge stack.

Module rules follow the route: under MNRE's memorandum of 4 August 2026, net-metering and open-access projects need ALMM List-I modules, and List-II cells if commissioned after 31 December 2026, while a private behind-the-meter plant used solely for captive consumption is outside both lists. Check our ALMM guide.

The environmental consent is a separate question. The CPCB's classification, in the version dated 24 August 2026, lists milk processing and dairy products as an industrial sector in the Red category for an integrated project, with small-scale units using coal or biomass as fuel in Red or Orange and units using PNG as fuel in Orange, while solar photovoltaic generation is classed White. A solar plant on a dairy site does not change the dairy's category, but check with your State Pollution Control Board whether your consent conditions need updating; see our guide to consent to establish and operate.

What risks are specific to dairies, and how does payback work?

The main risk is chilling continuity. A grid-tied solar plant stops when the grid fails, as a safety function, so it does not keep your chillers running in an outage; you still need the DG set and a clean changeover, and our guide to solar, DG and grid switching covers it. If outages are the main cost, a battery changes the case; see our page on battery energy storage.

The second risk is the time-of-day tariff. Where your state applies it, units generated in solar hours are valued at the solar-hour rate, so payback is judged against that rate. Our guide to contract demand and ToD tariffs shows how billed demand behaves.

On cost, our published band for rooftop C&I solar is ₹24,000–32,000 per kW excluding GST, indicatively ₹28–32 lakh at 100 kW and ₹68–75 lakh at 250 kW on our size pages. Payback is the capital cost against the bill you stop paying, so it rests on how much generation your daytime load absorbs. Run it in the solar payback calculator with your own tariff.

How Secured Engineers helps

We design C&I solar in-house, file DISCOM net-metering, Fire NOC and CEIG applications in-house, and deliver MEPF and solar under one contract, which matters on a dairy site where the refrigeration plant, the fire system and the electrical room share the same footprint. We work from offices in Noida (Delhi NCR) and Ludhiana, with 535+ projects across 18+ states and 89.77% repeat clients.

Send twelve months of bills, the sanctioned load and a roof or yard drawing, and we will show the plant size your daytime load supports and the route that applies. See our solar for factories page, message us on WhatsApp, call +91 70099 85817, or ask for a free proposal.