Manufacturing sites are attractive solar hosts – large roofs, high daytime consumption, strong tariffs to displace. The complications are rarely about the array.
Industrial electrical loads are lumpy in ways commercial buildings are not. A large motor starting, a welding operation, an induction furnace cycling – these produce demand steps of hundreds of kilowatts within seconds.
Consequences for solar design:
The practical constraint that most affects programme.
Work above an operating production line raises questions that do not arise on a warehouse: what happens if a tool is dropped, whether the process below can tolerate vibration or dust, whether hot works are permissible, whether roof access requires the line to stop.
Many sites conclude that array installation over live production areas is restricted to planned shutdown windows. If your shutdown is two weeks in August, the installation programme is dictated by that, not by crew availability.
Plan this early. A project that assumes continuous access and discovers otherwise loses a season.
Process exhaust changes roofs. Sites handling chemicals, foundries, food processing with fat-laden vapour, anything venting corrosive or greasy air – the roof surface downwind of a stack is often in materially worse condition than the rest.
Two implications: the structural and membrane assessment needs to consider localised deterioration rather than average condition, and array placement should avoid the immediate deposition zone around exhaust stacks. Modules in a grease or chemical plume soil rapidly and can suffer accelerated frame and glass degradation.
Connecting the array to the main switchboard requires an outage on that board. On a manufacturing site this is a significant event requiring planning, and it may only be possible during an existing shutdown.
Where the connection can be made to a spare way on an existing board, or via a new board fed from an existing spare breaker, the outage may be short. Where the main board is full and needs modification or replacement, it is a substantial piece of work.
Establish switchboard capacity and spare ways at feasibility stage. Discovering the board is full after design is a common and costly surprise.
Industrial sites have permit-to-work systems, lockout-tagout procedures, confined space rules, hot work permits and contractor induction requirements. A solar contractor unfamiliar with industrial safety regimes will be slower and will generate friction.
Factor into evaluation: has this contractor worked on operating industrial sites before? The technical work is the same; the administrative overhead is not, and contractors who have only done warehouses and offices consistently underestimate it.
On most manufacturing sites the energy story has three parts, in descending order of return:
Doing these in reverse order is common because generation is the visible, fundable project. It also means sizing an array against a consumption figure that better housekeeping would have reduced. Audit first.