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For a South African business considering commercial solar in 2026, the first question is usually straightforward: how much will the system cost? The useful answer requires a closer look at how the business consumes electricity, when that consumption occurs, the tariff it pays, the physical characteristics of the site and what the energy system needs to achieve.
A manufacturing plant operating heavy machinery throughout the working day has a very different energy profile from a shopping centre with extended trading hours, an agricultural operation with seasonal demand or a warehouse with relatively low daytime consumption. Each may install solar PV, yet the system design, required storage capacity, financial return and appropriate capital investment can differ significantly.
This is why commercial solar should be approached as an energy and financial engineering decision. The objective is to design a system around the economics and operating requirements of the business, with the capital cost assessed against the savings and operational value it can generate over its useful life.
What businesses can use as a commercial solar cost benchmark
The benchmarks in GreenCape’s Energy Services Market Intelligence Report 2025 provide a useful reference point for commercial solar pricing in South Africa. However, these figures should be regarded as market benchmarks rather than fixed 2026 prices. Actual EPC costs will vary depending on system size, equipment selection, site conditions, electrical infrastructure and engineering requirements. For context, the report’s 2024/25 figures place outright-purchase installation costs for systems between 500 kWp and 1 MWp at approximately R11.50 to R14 per watt, while costs for projects above 1 MWp range from approximately R11 to R13.50 per watt. Smaller projects generally carry a higher unit cost, reflecting the economies of scale achieved as system size increases.
GreenCape uses an overall installed solar PV cost assumption of R14/Wp when modelling growth in the commercial, industrial and agricultural market and expects the sector to add approximately 3.8 GW of embedded PV capacity by 2030, representing an estimated R53.2 billion in investment.
These figures offer businesses a starting point for budgeting, while the final project cost is shaped by the system that can produce the greatest value at a particular site.
Roof structure and available space influence the engineering approach. GreenCape estimates that conventional rooftop PV can typically accommodate around 200 Wp per square metre, while alternative configurations carry different cost profiles. Ground-mounted installations have an indicative cost multiplier of approximately 1.10 to 1.20 compared with conventional rooftop installations, carports range from 1.25 to 2.00 and rooftop projects requiring asbestos replacement from 1.30 to 1.50.
The right commercial solar budget therefore begins with the site and its electricity data rather than a predetermined system size.
Start with the electricity bill and load profile
Historical electricity consumption provides some of the most valuable information in a commercial solar feasibility study.
A detailed assessment considers monthly and seasonal consumption, daytime demand, peak demand, operating hours, the applicable Eskom or municipal tariff, fixed charges, time-of-use periods and the extent to which solar production will coincide with consumption.
The relationship between generation and consumption has a significant influence on project economics. Electricity generated while the facility is consuming power can directly displace grid electricity. Generation that exceeds the site’s demand may require battery storage, export arrangements or curtailment, each of which changes the financial model.
GreenCape estimates that the difference between grid electricity costs and the levelised cost of embedded solar PV can translate into savings of approximately 40% to 60% on the electricity displaced by solar for commercial, industrial and agricultural users. The report also makes clear that actual savings depend on the customer’s tariff structure and usage pattern.
Tariff analysis has consequently become as important as panel capacity. Electricity prices for commercial, industrial and agricultural Eskom customers increased by more than 600% in nominal terms between 2009 and 2024, strengthening the business case for companies seeking greater control and predictability over energy costs.
An illustrative commercial solar investment
Consider a facility consuming an average of approximately 121,433 kWh of electricity per month and paying an average electricity bill of around R350,720.
An energy assessment identifies an opportunity for an 885.6 kWp solar PV array supported by approximately 1.68 MWh of battery storage. The solar system supplies daytime demand, while the battery can store solar or lower-cost off-peak grid electricity and discharge during higher-priced peak periods. A generator can form an additional resilience layer where the operating environment requires it.
Using an assumed 5.5 peak sun hours per day and an 85% performance factor, the 885.6 kWp array could produce approximately 4,140 kWh per day, or roughly 124,200 kWh in a 30-day month. Actual financial performance would depend on how closely that generation coincides with the facility’s operating load.
Using GreenCape’s 500 kWp to 1 MWp rooftop benchmark of approximately R11.50 to R14/W, the PV component would indicate an installed capital range of roughly R10.2 million to R12.4 million.
Battery storage then adds a second layer to both the investment and the value created. GreenCape uses an indicative total installed cost of R5,000/kWh for battery energy storage when modelling the South African behind-the-meter market. At approximately 1.68 MWh, that benchmark would imply around R8.4 million of installed battery capacity.
On these market benchmarks, the combined PV and battery components of the illustrative system would therefore sit at approximately R18.6 million to R20.8 million. Final EPC pricing would incorporate the specific engineering design, equipment selection, electrical infrastructure, site conditions and any additional resilience requirements.
The more important calculation is what that capital is expected to achieve. Under the illustrative operating assumptions, strong daytime self-consumption could generate approximately R220,000 per month in PV-related electricity savings. Battery peak shaving and tariff arbitrage could contribute a further approximately R50,000 per month, producing an estimated combined saving of around R270,000 per month, or approximately R3.24 million per year at the initial tariff assumptions.
Against the indicative PV and BESS capital range, this produces a simple illustrative payback period of approximately 5.7 to 6.4 years before factors such as financing structure, tariff escalation, taxation, maintenance and any additional resilience infrastructure are incorporated.
That calculation also demonstrates why system sizing needs to follow the energy data. A larger PV array does not automatically create a stronger return if a facility cannot consume, store or economically export the additional generation.
Similarly, batteries create considerably more financial value where they can perform several functions within the same system. Peak shaving, tariff arbitrage, load shifting and power-quality support are among the value-stacking opportunities available to commercial and industrial energy users. On time-of-use tariffs, batteries can charge when electricity is less expensive and discharge when grid electricity carries a higher peak-period rate. They can also store surplus solar production for use later in the day, improving the proportion of renewable energy consumed on site.
For a business with high peak-period demand, the battery may contribute directly to the investment return. For another operation, its strongest value may come from protecting production, managing grid interruptions or making better use of excess daytime solar generation. Rentech’s role as EPC partner is to identify the combination that fits the operating and financial priorities of the site.
Real-world savings depend on how the business operates
As a leading printing and packaging manufacturer in South Africa, Oranje Print and Packaging partnered with Rentech to implement a large-scale solar energy solution at their Senekal production facility.
The production facility uses a 378 kWp solar installation with three 125 kW inverters and a 221 kWh battery energy storage system. The solution was designed around the energy requirements of a high-energy production operation, using solar generation and storage to optimise electricity consumption and manage peak demand. The installation is delivering approximately R100,000 per month in electricity cost savings while reducing grid reliance and improving energy use during production hours.
The saving becomes more meaningful when viewed as part of the operating cost base. Approximately R100,000 per month equates to around R1.2 million per year at current performance levels. Over a multi-year investment horizon, avoided electricity expenditure can become a significant contributor to the project’s overall financial return, particularly as grid tariffs change.
This is the distinction between buying solar equipment and engineering an energy solution. The financial opportunity comes from understanding how generation, storage, tariffs and operations work together.
An effective commercial solar project is sized around the energy that the operation can productively use, the tariff costs it can avoid and the resilience the organisation requires. For some businesses, the strongest case will centre on daytime solar generation. For others, battery storage, peak management and operational continuity will contribute substantially to the return.
This is where detailed EPC engineering turns a broad question about the price of solar into a much more valuable answer: what energy system will deliver the strongest long-term commercial outcome for this particular operation?