Learn how to assess a solar investment for an industrial facility using the consumption profile, roof suitability, the generation model, self-consumption and financial scenarios.
Short answer: A solar investment for an industrial facility is not planned around how many panels fit on the roof; it is planned from the facility's time-based electricity consumption, the suitability of the roof and electrical infrastructure, the self-consumption ratio and realistic financial scenarios. A sound feasibility study brings the technical design and the cash flow together under the same set of assumptions.
This guide is for general information. Regulations, tariffs, equipment prices and connection conditions can change over time. The final decision should rest on current documentation, authorised engineering work and the results of a survey specific to the facility.
What question does an industrial solar feasibility study answer?
The purpose of a feasibility study is not only to answer "how many kWp can be installed?". Sound work shows the difference between the capacity that can be installed and the generation the business can actually use, makes technical risks visible, and compares different investment options against the same criteria. Even if the roof's physical capacity is high, simply filling the area may not be economically appropriate if daytime consumption is low.
Installed capacity is expressed in kWp and generated energy in kWh. Two systems with the same kWp rating generate differently because of orientation, pitch, temperature, shading, soiling, inverter selection and grid outages. A single regional average therefore cannot be the sole basis for an investment decision.
Why is the consumption profile the first step?
At least 12 months of bills show the seasonal variation; but for an industrial facility, hourly or 15-minute meter data should be used wherever possible. The production line's shift pattern, weekend working, planned shutdowns and the summer-winter load difference determine how much of the generation will be consumed at the same time. This match is the basis of the self-consumption ratio.
If new machinery, an electric vehicle fleet, a heat pump or a capacity increase is planned, these should be added to the model as separate scenarios. Carrying past consumption forward unchanged can lead to a system that is either too small or too large. Contracted capacity, the power factor correction arrangement, and transformer and main board details are also starting data for the electrical design.
How are the roof and load-bearing structure assessed?
The net usable area is smaller than the roof plan. Rooflights, smoke vents, parapets, maintenance walkways, fire access, shade-casting equipment and safe edge clearances must all be factored into the layout. The connection detail used for a sandwich panel, trapezoidal metal or reinforced concrete roof differs in each case; waterproofing and corrosion risk are examined separately.
Structural suitability is not confirmed by looking at panel weight alone. The existing load-bearing structure, connection points, wind uplift forces, snow load and regional conditions must be assessed by an authorised specialist. Where necessary, the cost of strengthening and its effect on the production facility during the works are included in the feasibility study.
What checks are made on the electrical infrastructure?
The single-line diagram, transformer capacity, main distribution board, short-circuit withstand, cable routing, earthing and protection coordination are addressed together. The positioning of the inverters affects DC and AC cable distances, while temperature and ventilation conditions affect the equipment's operating environment. Fire detection, emergency access and occupational health and safety requirements should be clarified at the start of the project.
A monitoring system is not just a live generation screen. Monitoring the inverter, the meter and the facility's consumption on the same timeline makes it possible to detect performance losses, faults and unexpected changes in consumption early.
What assumptions should the generation model include?
The model should explicitly state long-term irradiation data, the panel plane, horizon and near shading, temperature losses, inverter efficiency, DC/AC cable losses, mismatch, soiling and availability assumptions. Rather than presenting only an annual total, monthly generation, specific yield and a loss diagram should be shared.
The result is a long-term expectation rather than a weather forecast. Any single year may be sunnier or cloudier. The economic model should therefore include, alongside the base case, more cautious scenarios that show sensitivity to changes in generation and tariffs.
How should the financial analysis be set up?
The investment amount should cover, beyond the panels and inverters, the mounting structure, design, applications, board and transformer modifications, cabling, access equipment, commissioning, monitoring and, where required, roof strengthening. During the operating period, maintenance, cleaning, insurance, possible equipment replacements and financing costs are separate line items.
The savings calculation should not rest on the assumption that every kWh generated has the same value. Self-consumed energy should be separated from surplus generation, which may be subject to different rules; current tariffs and regulations should be verified as at the project date. The payback period should be read not as a single definitive figure but as a range of outcomes tied to stated assumptions.
Comparing quotations on the same basis
- Compare the full make and model of the panels and inverters, along with quantities.
- Ask for the layout plan, installed capacity, annual generation and all loss assumptions.
- Equalise the scope of the structural study, electrical design, protection equipment and earthing.
- Get site safety, access, crane or scaffolding and production-interruption responsibilities in writing.
- Separate the product, performance and workmanship warranties from one another.
- Compare commissioning tests, acceptance criteria, monitoring access and the maintenance service.
A quotation with an unclear scope can look cheap at first sight. If excluded works, the payment schedule and change management are not set out in writing, it becomes difficult to anticipate costs that emerge later.
Frequently asked questions
At least 12 months of bills, hourly or 15-minute consumption data where possible, the contracted capacity, the single-line diagram, the roof plan and information on future load growth are needed.
No. Because self-consumption is determined by the hours in which generation matches consumption, time-series data gives a sounder result.
No. A forecast is an engineering model based on irradiation data, site geometry, equipment and loss assumptions.
Deciding on the total price alone, without first equalising the scope of the quotations, is not sound.
Conclusion: the decision file must be traceable
A good industrial solar feasibility study presents its data sources, technical assumptions, generation losses, investment scope and financial scenarios in a traceable form. Management then sees not only the headline figure but also the conditions under which that figure holds. You can review our commercial rooftop solar solutions or contact Turuncu Solar for a preliminary assessment using your facility's data.
Cover photograph: Ayman Nakib Badhan, "Powering Progress 2", Wikimedia Commons, CC BY-SA 4.0 . The image has been resized for the web and converted to WebP. Source image .
