SBSW, SRGHY: South African Power Tariffs Outpace CPI, Fuel Self-Generation

Sibanye-Stillwater (SBSW) and Shoprite Holdings (SRGHY) each disclosed the same regulatory driver on their September 1, 2026 earnings calls: a NERSA-approved annual electricity tariff increase of 13% and 12.7% respectively, confirmed independently by two unrelated South African issuers on the same day.

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Why the tariff, not blackouts, is now the reason to self-generate

South Africa's electricity price is set centrally by the National Energy Regulator of South Africa (NERSA), not by market supply and demand. For years, companies built private solar or wind capacity mainly to hedge against Eskom load shedding - rolling blackouts caused by insufficient generation capacity that could shut down factories and stores with little warning.

But according to Business Day's coverage of Eskom's latest annual results, the utility posted its best reliability in six years this fiscal year, running 441 consecutive days without load shedding, and booked a profit of R30.3 billion [3]. The reliability case for private generation has largely disappeared. Yet Sibanye, Shoprite and chemicals-and-energy producer Sasol (SSL) did not slow their self-generation build-out this year - they kept expanding it, because the tariff itself is rising faster than companies can pass costs through. Sasol disclosed more than 500 megawatts of renewable capacity brought online this year, saying the projects are "already lowering costs" [4], though its call never mentioned Eskom, NERSA or tariffs - making it a directionally consistent but independently unconfirmed data point.

The shift is already visible on specific cost lines. DRDGOLD, consolidated within Sibanye's group, disclosed that solar power cut the Eskom electricity drawn per tonne processed at its Ergo plant from 13.6 kWh to 8.6 kWh, saving an estimated ZAR 13.50-14.50 per tonne [5]. Because DRDGOLD sits inside Sibanye's own group, this figure is not independent cross-confirmation, but it shows self-generation moving from an environmental line item to a number that belongs in a cost model.

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How big the cost hit is at each company

Sibanye said on its call that electricity now makes up 25% of working cost, and that electricity prices rose 13% "with the regulator" [1]. The tariff increase strikes directly at its core cost structure, and it is a variable the company cannot control.

Shoprite disclosed that its electricity and water expense rose 19.2% year over year, attributed directly to NERSA's 12.7% tariff increase, while the retailer's own average selling-price inflation was only 0.8%, with two of its store banners actually in deflation [2]. The regulated tariff increase is more than ten times the retailer's own pricing power - a cost gap it cannot pass on to shoppers and must instead absorb by cutting its own power bill.

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Eskom is losing its best-paying customers, and regulators are responding

Eskom's own results show industrial electricity sales volume fell 22.5% this fiscal year, total sales volume fell 6.2%, and revenue grew only 4.1% - far below the 12.74% tariff increase [3]. These industrial and large retail customers are Eskom's most reliable, highest-bargaining-power load; as they shift to self-generation, the utility loses its most profitable demand. Revenue growth lagging the tariff increase typically means the next rate hike will need to be larger, with the gap ultimately falling on municipal and residential customers who cannot self-generate. Whether this pattern persists depends on whether Eskom's industrial sales volume and revenue growth continue to diverge from tariff increases in coming quarters.

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Companies this could affect

• Exxaro Resources (EXXAF): Another South African miner that disclosed its own 10.6% tariff increase in fiscal 2026; its 68-megawatt Lephalale solar plant already covers 30% of that mine's energy needs and saves an estimated R100 million a year - another company that has already turned self-generation into a quantified cost saving under the same mechanism [6].
• Harmony Gold (HMY): Disclosed a year earlier that labor plus electricity made up 72% of group costs and built a 100-megawatt solar plant to mitigate tariff increases [7]; its most recent earnings call made no mention of electricity, Eskom or solar at all - the exposure has not changed, it has simply stopped being discussed [8].
• Reunert (RNRTY): Its renewable energy business generates and wholesales power specifically to lower commercial and industrial customers' electricity costs, with over 100 megawatts of equity interest in built solar assets and a signed power purchase agreement with Tiger Brands - a company selling the "escape" itself [9].

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Sources

[1] Drillr · Sibanye-Stillwater (SBSW) · 2026-09-01 · H1 2026 earnings call

"of the working cost, 25% of the working cost is electricity, and electricity did go up by 13% with the regulator."

[2] Drillr · Shoprite Holdings (SRGHY) · 2026-09-01 · FY2026 full-year earnings call

[3] Business Day · "Eskom profit more than doubles but weaker sales pose new problem" · 2026-08-31 · News report · https://www.businessday.co.za/news/2026-08-31-eskom-profit-more-than-doubles-but-weaker-sales-pose-new-problem/

[4] Drillr · Sasol (SSL) · 2026-09-01 · FY26 annual results call

[5] Drillr · DRDGOLD (DRD) · 2026-08-19 · FY2026 earnings call

[6] Drillr · Exxaro Resources (EXXAF) · 2026-08-20 · H1 2026 earnings call

[7] Drillr · Harmony Gold (HMY) · 2025-08-28 · FY2025 earnings call

[8] Drillr · Harmony Gold (HMY) · 2026-08-27 · FY2026 earnings call

[9] Drillr · Reunert (RNRTY) · 2026-05-25 · H1 2026 earnings call

This is meant to help you spot overlooked industry shifts and companies - not a stock recommendation.