Eskom's FY2027 Wheeling Rebate Erosion Is Now the Silent Killer of C&I Wheeled PPA Economics: What the GCC Energy-Charge Exclusion and the Ancillary-Services Rebate Removal Mean for Every Off-Taker Repricing a Wheeling Contract After April 2026

The Silent Killer: How Eskom's FY2027 Tariff Restructuring Is Gutting Wheeled PPA Returns

If you signed a wheeled Power Purchase Agreement (PPA) before April 2026 and haven't revisited your financial model since, stop what you are doing. Eskom's FY2027 tariff changes — effective 1 April 2026 for direct customers — have fundamentally restructured the economics of third-party wheeling in ways that are not visible on any headline tariff increase percentage. The 8.76% average increase is the number that made the press. The two structural changes buried in the schedule of standard prices are the ones that are quietly destroying deal economics across the Commercial & Industrial (C&I) wheeling market.

What NERSA Approved and What Eskom Implemented

On 5 March 2026, NERSA approved Eskom's FY2027 tariff adjustment application. Eskom confirmed implementation on 16 March 2026, with new tariffs taking effect on 1 April 2026 for non-municipal (direct) customers. Municipal bulk purchasers implement their own increases — averaging 9.01% — from 1 July 2026, in line with the Municipal Finance Management Act (MFMA).

The headline number — 8.76% average increase — is NERSA-approved and reflects the allowable revenues under the MYPD6 multi-year pricing determination. On a standalone basis, an 8.76% tariff escalation, while above CPI, is manageable within most PPA models that include an annual escalation clause. What is not manageable — and what no escalation clause anticipated — are the two structural changes to how wheeling credits are calculated.

Change 1: The GCC Energy-Charge Exclusion — The Invisible Toll Booth

The Generation Capacity Charge (GCC) is the mechanism NERSA approved to allow Eskom to recover fixed generation capacity costs in a more transparent, unbundled manner. It is being phased in over three years:

• FY2025: 20% recovered as a fixed standalone GCC charge; 80% embedded in the energy (c/kWh) rate
• FY2026: 20% fixed GCC; 80% still embedded in energy rate
• FY2027: Fixed GCC raised to 30%; remaining 70% still embedded in the energy rate

In isolation, this looks like a gradual structural shift toward fixed-cost recovery. For a standard Eskom retail customer consuming from the grid, it is largely revenue-neutral by design. But for a wheeling off-taker, it is anything but neutral. Eskom's FY2027 Schedule of Standard Prices states this explicitly: "to ensure comprehensive customer contribution, this portion of the GCC included in the energy charge is excluded from the energy credit provided under wheeling and net-billing (offset) transactions."

In plain language: the WEPS-based energy credit that an off-taker receives on their Eskom account for every kWh wheeled from an IPP is now calculated on a WEPS rate that already has the GCC energy-component stripped out. The credit per kWh wheeled is lower than the gross retail energy rate the customer is billed at. The GCC-embedded portion of the energy charge — representing 70% of the total GCC in FY2027 — remains on the customer's bill but is not offset by the wheeling credit. The off-taker pays it in full, regardless of how much renewable energy they wheel.

This is the silent toll booth. Every kWh of wheeled solar or wind energy that passes through Eskom's network now carries a non-rebatable GCC surcharge. For a Megaflex or Miniflex C&I customer wheeling energy at medium voltage (>500 V to ≤66 kV), this is a material, unrecoverable cost that directly compresses the net saving per kWh versus the Eskom retail counterfactual.

SolarXgen field observation: On wheeling contracts repriced post-April 2026, we are seeing the effective wheeling cost to off-takers — inclusive of the GCC exclusion — running materially above pre-reform comparable periods, even after accounting for the below-NERSA PPA rate offered by the IPP. The GCC exclusion is not a rounding error. It is a structural cost floor that has entered the system and is compounding annually as the GCC phase-in progresses toward FY2028.

Change 2: The Ancillary Services Rebate Removal — Death of a Line Item

The second change is older in origin but equally damaging in its current cumulative effect. Under the Eskom Retail Tariff Plan (RTP) reforms first implemented in FY2026, Eskom confirmed that charges related to non-Eskom generators using the Eskom network to transport electricity would no longer be rebated. The reasoning: the new unbundled tariff structure was said to provide for "better charging, reflecting the configuration of the network."

The Ancillary Service Charge — defined in Eskom's tariff schedule as "the charge that recovers the cost of providing ancillary services by the System Operator" — is a c/kWh charge applied on the total active energy consumed at a point of delivery. Historically, under legacy wheeling arrangements, a portion of the ancillary services cost was rebated to off-takers as part of the broader wheeling credit calculation, on the rationale that wheeling IPPs contribute to system stability or at minimum displace the need for some ancillary services.

That rebate is gone. The ancillary service charge now sits as a full, unrecoverable pass-through cost on every kWh consumed at the off-taker's Point of Delivery (POD), whether that energy is wheeled renewable energy or drawn directly from Eskom's grid. The wheeling credit mechanism does not offset it. The IPP cannot absorb it without raising the PPA tariff. The off-taker pays it in its entirety.

Combined with the GCC exclusion, the effective net saving per kWh that a wheeling off-taker achieves against their Eskom retail bill has been permanently reduced — not by the PPA rate, not by generation performance, but by regulatory tariff restructuring that no existing PPA contract could have anticipated at the time of financial close.

The Compounding Effect on Wheeling PPA Economics

Consider a prototypical C&I wheeling off-taker: a manufacturing facility connected at medium voltage (MV) in an urban Eskom-supplied area, on a Megaflex tariff, with an NMD of 3–5 MVA. Pre-April 2026, the wheeling model worked as follows:

1. Off-taker pays Eskom their full Megaflex retail bill (energy + network + GCC + ancillary services)
2. Eskom raises a credit (rebate) equal to the WEPS rate — previously inclusive of the GCC energy component and the ancillary services contribution — for every kWh of energy certified as wheeled from the IPP
3. The off-taker settles the net Eskom account, then pays the IPP separately at the agreed PPA rate
4. Net saving = (WEPS credit rate – PPA rate) × volume wheeled, minus wheeling losses

Post-April 2026, Steps 2 and 4 are broken. The WEPS credit rate used in Step 2 now excludes the GCC energy-embedded component. The ancillary service charge in Step 2 is no longer rebated at all. The off-taker's net Eskom account is higher for the same volume of wheeled energy. The net saving in Step 4 shrinks materially — even if the PPA rate and volume remain constant.

What makes this particularly acute is the distribution loss factor change that accompanied the FY2026 reforms: loss factors for connections between >500 V and ≤66 kV increased from 9.6% to 15.6%, effectively increasing the cost of using the grid by approximately 6%. Layered on top of the GCC exclusion and ancillary services rebate removal, the cumulative hit to wheeled PPA economics for a mid-voltage C&I off-taker is not marginal — it is transformative.

What This Means for Every Off-Taker Repricing After April 2026

If you are an off-taker currently renegotiating, extending, or entering a new wheeled PPA, the following is non-negotiable due diligence:

• Remodel your Eskom credit at the correct WEPS-ex-GCC rate. Do not use the headline retail energy rate as your credit proxy. The WEPS rates used for wheeling reconciliation now exclude the GCC energy component. Using the wrong rate will overstate your saving.
• Budget the ancillary service charge as a sunk cost. It is not rebatable. Include it in your true cost of electricity baseline regardless of wheeling volume.
• Stress-test against FY2028 GCC phase-in. The GCC fixed portion increases again in FY2028 as the three-year phase-in continues. Each increment means a larger proportion of the GCC is theoretically recoverable as a standalone fixed charge — but the energy-embedded component's exclusion from the wheeling credit continues to apply to the remaining portion embedded in energy rates.
• Revisit loss factor assumptions. If your wheeling contract was modelled on pre-FY2026 distribution loss factors, your volume-adjusted credit is already understated.
• Consider the behind-the-meter alternative seriously. For off-takers with the roof area, land, or substation capacity, behind-the-meter generation paired with Battery Energy Storage (BESS) for peak shaving now offers a structurally superior risk-adjusted return profile compared to wheeled PPAs, precisely because the GCC and ancillary service charges apply to consumption from the grid — not to self-generated energy consumed before the POD.

The Regulatory Trajectory: FY2028 and Beyond

Eskom's Retail Tariff Plan is not complete. The GCC phase-in continues into FY2028, and the broader unbundling trajectory — moving toward cost-reflective, fully separated generation, transmission, and distribution charges — will continue to erode the value of volumetric energy credits. The wheeling credit mechanism, which was designed for a world where Eskom's tariff was a single blended energy rate, is being progressively hollowed out as that blended rate is decomposed into components — some rebatable, many not.

South Africa's transition to a competitive electricity market, the development of the Transmission System Operator (TSO), and the evolution of the Wholesale Electricity Pricing System (WEPS) will ultimately create a more rational framework for wheeling. But that transition will take years. In the interim, every C&I buyer who signed a wheeled PPA under the pre-RTP tariff paradigm is sitting on a contract that is delivering less value than the financial model promised — and that gap is widening with each tariff cycle.

The question for off-takers is not whether to act. It is whether to renegotiate, restructure, or exit — and whether the developer on the other side of the PPA has the sophistication and balance sheet to accommodate a repricing conversation before the 2027 winter peak period arrives.

At SolarXgen, we are actively working with off-takers across the C&I spectrum to model the true post-FY2027 cost of wheeled energy versus behind-the-meter alternatives, and to structure PPA terms that are durable across the ongoing tariff reform cycle. If you are repricing a wheeling contract right now, the time to act is before your next Eskom billing cycle — not after.