Industrial Solar Power Solutions: A Practical Guide for Factories and Large Facilities
For a factory in Germiston, Isando or Rosslyn, electricity is not just an overhead. It is a production input, as essential as raw materials or labour, and it has become one of the hardest costs to budget for. Rising tariffs, maximum demand charges and the ongoing risk of supply interruptions have led many Gauteng manufacturers to look seriously at industrial solar power solutions.
But industrial solar is not simply a bigger version of a home system.
Factories have heavy, variable loads, three-phase supply, strict uptime requirements and regulatory obligations that households never face.
This guide answers the three questions we hear most often from plant owners and facility managers.
How does solar power benefit industrial facilities?
The most immediate benefit is industrial energy cost reduction. Most factories use the bulk of their electricity during daylight hours, which is exactly when solar panels generate power. Every kilowatt-hour produced on your roof is one you do not buy from the grid, and because manufacturing loads tend to run steadily through the working day, a well-sized system can put almost all of its output to direct use.
Predictability and resilience
Once installed, a solar system has low and largely fixed running costs. That helps shield the business from future tariff increases, which are set through NERSA‘s price determinations for Eskom and municipalities.
Paired with battery storage, solar can also keep critical processes running during outages, such as control systems, refrigeration, IT and lighting. This matters in parts of Johannesburg and Ekurhuleni, where local network faults and infrastructure failures can interrupt supply regardless of national grid conditions.
Tax and sustainability benefits
Under Section 12B of the Income Tax Act, businesses can generally deduct 100% of the cost of qualifying solar PV systems up to 1 MW in the first year. Larger systems are written off over three years at 50%, 30% and 20%. The temporary 125% enhanced incentive ended on 28 February 2025, so be wary of older articles that still quote it. Your accountant should confirm how the allowance applies to your business, and our guide to Section 12B solar tax incentives explains it in more detail.
You can also check the latest guidance from SARS.
Large-scale solar power also lowers a facility’s carbon footprint. This is increasingly relevant for manufacturers supplying export markets or corporate customers with emissions-reporting requirements.
How do you determine the solar capacity a factory needs?
Sizing a factory solar installation starts with data, not roof space. The best starting point is interval metering data: the half-hourly consumption records that most large Eskom, City Power and municipal customers can access.
This reveals your load profile, showing when you use power, how much, and how it varies across shifts, weekdays and seasons.
Matching generation to demand
From this data, a designer identifies your daytime baseload, the minimum level of consumption your facility maintains while the sun is up. Sizing close to this level means most of what you generate is used on site. Oversizing without a plan for the surplus can waste energy, particularly if your supplier limits or does not compensate power exported back to the grid.
Site and structural considerations
Next come the physical constraints. Roof orientation, shading and structural strength all matter, and older warehouse roofs in areas such as Wadeville, Spartan or Pretoria West may need an engineer’s assessment before carrying panels. Where roof space falls short, ground-mounted arrays or solar carports over staff parking can add capacity.
Gauteng’s climate works in your favour. The Highveld enjoys strong sunshine for much of the year, although summer afternoon thunderstorms can reduce output between roughly November and March. A good design models these seasonal variations rather than assuming ideal conditions.
Compliance and approvals
Regulation also shapes the design. Grid-connected generation facilities above 100 kW generally need to be registered with NERSA, in addition to approval from your electricity supplier, whether that is Eskom, City Power, or a municipality such as Tshwane or Ekurhuleni. Requirements differ between suppliers, and City Power revised its embedded generation application process in 2026, so build approval timelines into your project plan from the start.
Can industrial solar systems support heavy machinery?
Yes, with the right design. The challenge with heavy machinery is not only its running load but its starting load. Large motors, compressors, chillers and pumps can briefly draw several times their normal current when they start up.
This is known as inrush current, and an undersized inverter will struggle to cope with it.
Choosing the Right Installer
Not every solar provider is equipped for commercial-scale work. Look for a company with registered electrical engineers on the team, a track record with commercial and industrial clients, tier-one components with local after-sales support, and full compliance with SANS 10142 and grid connection requirements.
A proper energy audit, based on your actual consumption data rather than assumptions, should always precede any quote.
Grid-tied systems
In most grid-tied industrial solar systems, this is less of a concern. Solar supplies as much of the load as it can, and the grid seamlessly makes up the difference, including during motor start-ups. Your machinery runs as normal; the solar simply reduces how much you draw from the grid.
Backup and hybrid systems
Inrush current becomes critical when you want machinery to keep running during an outage. In that case, inverters and batteries must be sized for peak demand rather than average consumption, and loads must be balanced across all three phases.
Soft starters and variable speed drives (VSDs), which bring motors up to speed gradually, can significantly reduce these starting surges and make backup more achievable. In practice, many facilities choose to back up essential loads, such as control systems, critical production lines or cold storage, rather than the entire plant.
Getting industrial solar right
Industrial solar delivers its best results when it is designed around how your facility actually uses power. Before requesting quotes, gather 12 months of electricity bills and interval data, identify which processes cannot tolerate interruptions, and check the condition of your roof. With that information, an experienced installer can design a system that reduces costs, meets compliance requirements and supports your operations for years to come.
If you are weighing up solar for a factory, warehouse or large facility in Gauteng, speak to Solar Projects about a site assessment. You can also browse more solar guides for South African businesses on our blog.
Frequently Asked Questions about Solar Energy
- Cost reduction
- Energy independence
- Eco-friendly
- Incentive opportunities
- Property value
The answer, though, is simple: Large appliances. If you're running a central air conditioner (which uses about 2,000 kilowatt hours of electricity per year), heat pump, or clothes washer or dryer frequently, you could be consuming much more energy than you regularly do.
Yes, solar panels work on cloudy days, but they are significantly less efficient and produce about 10–25% of their normal power output. Sunlight still reaches the panels as a diffuse light source, and modern panels can still generate electricity, though much less than on a clear, sunny day. The exact amount of power generated depends on the cloud cover's thickness.
The size of the solar system you need depends on your energy consumption, the size of your roof, and the amount of sunlight your home receives. Get in touch today and let us help you determine the appropriate size for your needs.
While it is possible to install a solar system yourself, it is highly recommended to hire a professional solar installer (like us) to ensure that the system is installed safely and correctly.
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