Solar will not touch the kiln, and any contractor who says otherwise is selling. Where the electrical load actually sits in a ceramics or brick plant, what process dust does to glass, and which roofs to keep the array off.
Start with the disappointing part, because it saves everybody a month. The kiln is the largest energy consumer in a ceramics plant and in a brickfield, and it is thermal. Tableware, sanitaryware and tile plants fire on gas in tunnel and roller kilns. Brick kilns burn coal, whether they are fixed chimney, zigzag or hybrid Hoffmann. None of that energy appears on the electricity meter in a form a photovoltaic plant can displace, and anybody presenting a proposal in which rooftop solar makes a meaningful dent in a kiln's energy bill is either confused or selling.
What is left, once that is out of the way, is a genuine and often underestimated electrical load, and in a ceramics plant it happens to have almost exactly the shape solar wants.
The heat is gas. The motion is electric, and there is a great deal of motion.
Add those together and a ceramics plant has a substantial electrical base load that runs around the clock even though its heat comes from gas. That is a good profile for solar, because a correctly sized array is consumed entirely on site and nothing is exported. The plant will not run on sunlight, and it does not need to. It needs the daytime portion of a large steady consumption bought at a lower effective cost than the tariff.
A brick plant's electrical load is small by comparison: clay preparation with a mixer, pug mill and extruder, the induced draught fan on a zigzag kiln, water pumps, and lighting. The induced draught fan is usually the main continuous consumer and it is modest next to a ceramics plant's fan load.
Two things then complicate the picture. The first is seasonality. Brickfields fire through the dry season, broadly from the end of the monsoon to the pre-monsoon rains, and shut for the rest of the year. On the face of it that is a happy coincidence, because the operating season and the high irradiance season overlap. The complication is what happens during the idle months, when the plant generates and consumes nothing. Under net metering that becomes export credit, and export credit is only worth something if the arrangement lets you carry it forward far enough to use it. Ask the utility how the credit behaves across a long idle period before you size anything, because a credit that lapses is worth exactly nothing.
The second is that most brickfields have no building with a roof capable of carrying an array. The realistic option is a ground mount on the yard, and the yard is where green bricks are stacked and where trucks and trolleys move. Land use, not structure, is the constraint, and it needs settling with the operations manager rather than the accountant.
Both industries generate a soiling load that is worse than ordinary ambient dust, and in different ways.
Ceramics dust from body preparation, spray drying, pressing and glaze handling is fine, and a good deal of it is abrasive. Two rules follow from that. Never dry-wipe a module on a ceramics site, because dragging abrasive particles across glass with a cloth scratches it and a scratched module stays scratched for the rest of its life. And clean often enough that the deposit does not get wetted by dew and set, because a fine ceramic or glaze dust that has been damp and dried again behaves like a thin cement and needs far more work to remove.
Brickfield soiling is coal ash and clay, plus whatever the stack is emitting. Ash is alkaline, and wetted by dew it forms a film that rain does not clear. An array at a brickfield will need a cleaning regime through the firing season that most standard maintenance contracts do not budget for. That belongs in the contract at signing, priced against the actual site, rather than discovered in the first February.
On placement, the rule in both cases is the same: keep the array upwind of the stack and out of the plume, using the prevailing wind rather than an average of the whole year. Where the site geometry makes that impossible, accept the shorter cleaning interval and write it into the maintenance schedule.
The roof over the kiln hall is the obvious candidate on a site plan and the wrong one on site. It is hot, and module output falls as cell temperature rises, so an array there gives up yield in every hour of sunshine. On top of that, sustained high surface temperature is hard on the rubber and polymer components of a mounting system and on cable insulation routed across the sheet.
Better roofs on a ceramics plant are over the finished goods warehouse, the packing hall, the raw material store and the administration block. They are cooler, cleaner, less obstructed and structurally more predictable.
Two structural points that catch people out on this kind of plant. Ball mills and presses put vibration into the building, and vibration relaxes fasteners over time, so specify locking hardware and schedule a torque check at six and twelve months rather than only at the annual visit. And check whether the roof structure you are eyeing is tied into a crane runway, because a column and truss line carrying crane loads is not a line to add loading to without an engineer's assessment.
Before asking anybody for a quotation, get a month of interval data from the plant's HT meter and mark on it when the kiln fans, the ball mills, the spray dryer and the compressors run. That one chart will tell you more about whether a solar plant is worth building on this site than any generic feasibility report will, and any EPC contractor worth hiring will ask you for it before quoting a capacity.