ENERGY
Why the roof is not enough Rooftop solar has an important place in the energy conversation, but it cannot solve every energy problem. For many large commercial users, the limitation is simply that the roof is too small for the load.
Ginsberg points to Discovery’ s Sandton headquarters as an example. Rooftop solar installed on the building covers only about 3 % of its electricity consumption.
The constraint is not unusual. Growthpoint Properties, the JSE’ s largest real estate investment trust, has 61.2 MWp of solar installed across its portfolio, yet even that committed investment covers only 32 % of the group’ s total electricity consumption. To close the gap, Growthpoint signed a power purchase agreement with electricity trader Etana Energy in 2023 to wheel 195 GWh of wind, hydro and solar power annually to its buildings across multiple jurisdictions. The deal covers 70 % of consumption in participating buildings. Rooftop panels got them part of the way. Wheeling got them the rest.
Wheeling changes the geography of renewable procurement. It allows electricity generated in one location to be transported through the grid for use by a customer elsewhere, subject to the necessary commercial, technical, and regulatory arrangements. appeal to sustainability teams and to finance leaders trying to plan in a volatile cost environment.
Ginsberg argues that the tariff trajectory has become a central business concern. If Eskom tariffs continue rising above inflation, businesses that delay alternative procurement remain exposed to compounding cost increases.
The psychology of energy decisions matters. Rooftop solar is visible and easy to understand. Wheeling is newer, more contractual and less familiar. Five-year contracts can make decision-makers uneasy. What if technology changes? What if tariffs improve? What if the market shifts?
The default response is often to wait. But waiting has a price. Every month of delay is another month of exposure to utility tariffs and missed savings. As Pettit puts it,“ the cost of inaction is quantifiable, and it compounds”.
Businesses that understand their load profiles, tariff exposure, sustainability targets and procurement options will be better placed as the market evolves. Those that wait for perfect certainty may find themselves paying for the comfort of delay.
For companies with limited roof space, leased premises, multiple sites, or demand that exceeds on-site generation, this is significant. Ginsberg says Discovery Green’ s clients average around 90 % renewable energy coverage through its wheeling model, compared with far lower levels from rooftop-only installations. The model also allows for generation from different technologies and geographies, reducing reliance on one site or one weather pattern.
Rooftop solar can reduce exposure. Wheeling can form part of a wider procurement strategy. The generator was a panic purchase. The power purchase agreement belongs to a different business imagination.
Price certainty has become one of the strongest arguments for strategic energy planning. Companies want cleaner power, but they also want to understand and manage future costs. A renewable energy agreement with predictable annual escalations can
42 sabusinessintegrator. co. za