Commercial solar systems deliver two-year payback
By Kris Van der Bijl
COMMERCIAL solar systems in Cape Town are repaying their capital cost within two years, down from an industry benchmark of eight.
This is according to Billionetworks, the installer of a newly completed rooftop array at the Tribeca development in Bridgetown.
The claim lands in the same month that municipal electricity prices rise again. The National Energy Regulator of South Africa approved a 9.01% increase in the Eskom bulk purchase tariff for local authorities for 2026/27, effective from 1 July.
“Back in the day, people said eight years and you pay back your system,” said Shadley Bam, Alternative Energy Manager at Bilionetworks, which delivered the installation. “With grid-tied, our clients are paying it back within two years.”
Tribeca houses Vangate Shopping Centre and combines both other retail shops and residential units above. Property owner New Age Property Developments commissioned the system as its second project with Bilionetworks after seeing the results at an earlier site.
Bam puts the client’s current saving at R1 million a year on electricity, drawn from the company’s own billing comparisons.
How grid-tied solar systems cut costs for commercial property
The system at Tribeca has no battery storage. Its Sungrow inverters take direct current from the roof panels, convert it to alternating current, and feed it straight onto the building’s load.
According to Bam, an inverter of this type costs close to half the price of a battery-charging unit, because it carries none of the charging electronics.
Dropping the batteries costs the building nothing in backup. The Shoprite store already carries its own backup power as standard company infrastructure, so adding storage to the solar system would duplicate the cover the tenant already pays for.
The two-year payback depends on conditions holding. Load shedding has been suspended for an extended period, and a return of sustained cuts would change the sums for sites without their own backup. Rising tariffs push the other way, compressing payback with each annual increase.
The City of Cape Town’s own numbers show how widely that logic has spread. In budget documents tabled in March, the City projected a 1.1% decline in electricity sales volumes for 2026/27, attributing the drop partly to continued growth in small-scale embedded generation.
The same documents retain the SSEG feed-in incentive at 25 c/kWh, excluding VAT.
Solar panel obsolescence catches commercial buyers out
The panels feeding those inverters are 665 W units from AIKO – a Chinese supplier. This specification illustrates a second shift in the market. Bam said a 600 W panel counted as large a year ago.
By the time he specified this project, the 600 W class was obsolete and cost more than the unit replacing it. On his account, panel wattages turn over roughly every six months.
“Your string is only going to be as strong as your weakest panel,” Bam said. “I just say the weakest link breaks the chain.”
Bilionetworks therefore tells commercial clients to over-order at installation, holding around 20 spare panels on a 400-panel project. The advice serves the installer’s order book as much as the client, though the constraint underneath it is real.
Bam compares it to keeping spare tiles when building a house. The difference is that tiles stay on the shelf for decades, and a solar panel’s production run now ends before the system’s first service.
