Keeping the Line Under Control: Solar and BESS at Shree Ganesh Frozen Foods

Why solar alone does not keep a factory running

This is the question most buyers arrive with. The roof is covered in panels, the sun is out, the grid fails, and the factory still goes dark. It looks like a fault. It is not.

A grid tie inverter is required to shut down when the grid fails. The protection is called anti-islanding, and it exists so that a solar plant cannot keep a section of the network live while a lineman is working on it. It is not optional and it is not a defect. It does mean that an ordinary on-grid plant, however large, is a bill reduction measure and not a backup system.

Closing that gap takes a different class of equipment: a hybrid system that can form its own supply, disconnected from the grid, for whatever has been deliberately placed behind it.

The design question then becomes the interesting one. Not how big a battery, but what goes behind it.

What sits on the backup supply

At Shree Ganesh, the battery carries the plant's control and automation layer:

• PLCs and automation control panels
• HMIs, sensors and process instrumentation
• Canning line control circuits
• Filling and can seaming machine controls
• Packing machine controls
• Coding, batch printing and labelling equipment
• SCADA, data logging and production record systems
• Network, computers and communication equipment
• Emergency and essential production area lighting

Every item on that list is a control load. There is not a single motor, compressor or refrigeration drive among them. The cold store is not on the battery. Neither is the freezing plant, and neither are the line motors.

That segregation is what makes this an engineered system rather than a battery bolted onto a solar plant, and it is worth explaining plainly, because the instinct in the market runs the other way.

When a food plant loses power mid-shift, the expensive part is rarely the electricity it did not consume. What does not survive an outage is everything that was in motion: a can part way through seaming, a batch part way through a fill, a labelling sequence that stopped without recording where it stopped, a PLC that came back up with no memory of what the line was doing.

Restarting from that position is not a restart. It is an investigation. The line has to be walked, material between stages inspected, part-processed units judged and often discarded, controllers reset, sequences resynchronised and the batch record reconstructed. On an export order with quality documentation attached, that reconstruction is the part that hurts.

Holding the control layer up through the interruption changes the nature of the event. Machinery stops, because it has lost its supply. But it stops in a known state, under supervision, with instrumentation live and the production record intact. The operators can see what happened. When the grid returns, the plant resumes from a recorded position rather than an unknown one.

Why this makes the system smaller, not larger

There is a second consequence, and it is a commercial one.

Control loads are small and steady. They do not draw a starting surge the way a compressor does. A 30 kW power conditioning unit sitting in front of a 48 kWh bank is generously sized against that kind of load, which means the equipment is not straining, the battery is not being deep cycled to hold up a motor, and the hardware is not oversized to survive an inrush that never comes.

A system built instead to run refrigeration through an outage would need several times the power rating and several times the storage, would cost accordingly, and would still be at the mercy of the first compressor start after changeover.

The segregation is what makes the economics work. It is the design decision, not the equipment list, that carries the value here.

How the system operates

Normal operation. Solar supplies the factory's daytime demand as far as it goes, the grid supplies the balance, and the battery is held at its programmed reserve.

Grid interruption. The Growatt grid tie inverters disconnect, as they must. The hybrid unit takes the segregated control bus. Automation, instrumentation, records and essential lighting stay live. Motor driven equipment stops.

Grid restoration. Supply conditions are verified, loads are transferred back under the commissioned control sequence, and the battery returns to its charging and reserve mode.

Maintained by the people who built it

MGetEnergy holds a five year comprehensive maintenance contract for the site, covering the solar plant and the hybrid system together.

That matters more on a hybrid installation than on a plain rooftop. A solar plant announces its own problems through falling generation. A battery system does not. It can sit at apparent full health for months and fail at the only moment it was ever needed. Keeping it ready means monitoring state of charge and cell temperature, reviewing PCU alarms and event logs, confirming that the loads on the backup bus are still the loads that were designed onto it, and periodically proving the transfer under controlled conditions rather than assuming it.

What this means for other food processors

The useful question for a plant like this one is not how many kilowatts will fit on the roof. It is: which loads run during solar hours, which processes cannot tolerate an uncontrolled stop, and what has to stay alive for the plant to recover cleanly?

Answer those three and the solar sizing, the battery rating and the segregation follow. Start from the roof area instead and you get a plant that saves money and still leaves you reconstructing a batch record in the dark.

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