The Cost of Power
South African electricity is no longer cheap. The national average tariff reached about 195 ZAR cents per kWh (~R1.95/kWh) in 2024/25, rose a further 12.74% in 2025/26, and has climbed roughly 190% over the past decade — about 11% a year, far ahead of inflation. For a factory, mall, data centre or commercial estate, the trajectory matters as much as the level: every percentage point of wasted current costs more this year than last, and more again next year.
The level varies sharply by who supplies you. Large industrial users on Eskom’s time-of-use Megaflex tariff pay an effective rate of roughly $0.07–0.086/kWh, while commercial and municipal-supplied customers — where most low-voltage sites sit — pay more like $0.11–0.15/kWh. On a rising tariff of that order, recovering wasted energy and avoiding demand charges is a material, repeating saving.
| Who pays | Typical price | Notes |
|---|---|---|
| National average tariff | ~195 ZAR c/kWh (~R1.95/kWh, 2024/25) | Up ~190% in a decade; +12.74% in 2025/26 |
| Large industry (Eskom Megaflex, effective) | ~$0.07–0.086/kWh | Time-of-use; demand & reactive charges reward correction |
| Commercial / municipal supply | ~$0.11–0.15/kWh | Where most qualifying low-voltage sites sit — high bills |
| Households (Eskom Homepower, all-in) | ~R2.80–3.30/kWh (2025/26) | Web-sourced — varies by municipality and usage; see note |
National-average, Megaflex and commercial/municipal figures are drawn from Eskom and NERSA tariff schedules (2024/25 and 2025/26). Dollar figures use an indicative rate of about R16 to the US dollar; the rand can move materially, so treat them as orders of magnitude. The household figure is the Eskom Homepower all-in residential rate and is web-sourced for context — it varies by municipality, tariff option and consumption. Figures are current as of 2024–2026 and are revised annually — verify against the Eskom tariff schedules and NERSA at the time of reading, and against your own municipal tariff where you are not supplied directly by Eskom.
How You’re Billed
The headline cents-per-kWh is only part of the story. A larger South African site — on Eskom’s Megaflex or an equivalent municipal demand tariff — pays for the energy itself, for the network that delivers it, for levies, and, critically for power quality, for the maximum demand it draws (billed in kVA) and for the reactive energy it pulls when power factor is poor. On these tariffs the kVA maximum-demand charge is one of the largest line items on the bill — and it, along with the reactive-energy charge, moves directly when you correct power factor.
| Component | What it is | Cut by power quality? |
|---|---|---|
| Energy (active, c/kWh) | The kWh you consume, often time-of-use (peak / standard / off-peak) | Indirectly — lower network losses |
| Network / transmission & distribution | Use-of-network charges for delivering power to your connection | Partly |
| kVA maximum-demand charge | A charge on the highest apparent-power demand (kVA) recorded in the period | Yes — correcting power factor lowers kVA, so the charge falls |
| Reactive-energy charge (kVArh) | Levied by Eskom when power factor falls below 0.96 in the winter high-demand season | Yes — power factor correction clears it directly |
| Levies & surcharges | Statutory and municipal levies recovered on the bill | No |
So the answer to two questions South African operators often ask: yes, you are billed for kVA — through the maximum-demand charge that dominates a Megaflex-style bill — and yes, you are billed for poor power factor, through Eskom’s reactive-energy charge below 0.96. Both fall as power factor rises toward unity, which is exactly what correction delivers.
Power Factor & Regulation
South Africa makes the cost of poor power quality explicit. Eskom levies a reactive-energy charge whenever power factor falls below 0.96 during the winter high-demand season — so a site running at 0.85 power factor pays measurably more than the same site corrected to 0.98+, both in that reactive charge and in the inflated kVA maximum demand it registers. On demand-based tariffs like Megaflex, that kVA charge is central to the bill, which is why correction reads straight through to the bottom line.
On harmonics, supply quality is governed by NRS 048-2 (Edition 5, 2025), which sets compatibility levels including total harmonic distortion of ≤8% on low- and medium-voltage networks. Embedded generation — the behind-the-meter solar now on so many sites — connects under NRS 097-2. As inverters, variable-speed drives, rectifiers and non-linear UPS multiply, staying inside the NRS 048-2 limit increasingly requires active harmonic filtering, not just a one-off survey.
The reactive-energy / power-factor charge is set in Eskom’s tariff schedules (levied below 0.96 in the winter high-demand season); harmonic and supply-quality limits follow NRS 048-2 (Edition 5, 2025; THD ≤8% on LV/MV), and embedded generation connects under NRS 097-2. Eskom tariffs are approved by NERSA, and municipal tariffs are set separately by each municipality — so the exact demand, reactive and power-factor charges that apply to your connection vary by supplier and are updated annually. Confirm the charges and limits that apply to your site with Eskom, your municipality and NERSA.
Why Power Quality Matters Here
Three structural forces make power quality a South African boardroom issue, not just an engineering one. First, the tariff — already covered: high, and rising about 11% a year, so the savings case strengthens annually. Second, behind-the-meter solar: scarred by the blackout years, customers installed roughly 6.1 GW of behind-the-meter solar — 71% of it commercial — and that inverter base injects harmonics, voltage rise and reactive-power swings at exactly the commercial and industrial sites we serve. Third, grid fragility: South Africa held 300-plus outage-free days into 2026 after the record load-shedding of 2023 (roughly 329 days of shedding, ~10.6 TWh lost), but that recovery rests on an ageing coal fleet at about 60% availability and thin reserve margins, so resilience still matters.
Unlike a stable, low-cost grid, South Africa pulls every lever the same way: cost, compliance and resilience. The blackout era has eased, but the power-quality problem the rush to self-generation created has not — it is structural, and growing as more solar connects each year.
The Solution
HarmoniQ installs a coordinated, solid-state system at the low-voltage switchboard — where South African sites carry their cost, where the kVA demand and reactive-energy charges bite, and where behind-the-meter solar injects its distortion. We deploy three products as the site requires: the HarmoniQ Booster for real-time power factor correction, the HarmoniQ Filter (HPF) for harmonic mitigation, and HarmoniQ Alpha as the integrated platform tying correction, filtering and voltage stabilisation together. No switched-capacitor steps, no contactors, and no resonance risk with the harmonics your solar and drives already put on the system.
Real-time true power factor correction to 0.98+ across the whole network — clearing the threshold below which Eskom levies its reactive-energy charge, lowering the kVA maximum demand that dominates a Megaflex-style bill, and freeing transformer headroom so you can add load without a costly Eskom or municipal upgrade.
Active harmonic filtering that holds distortion within the NRS 048-2 limit (THD ≤8% on LV/MV) — the component that matters most in South Africa, where 6.1 GW of behind-the-meter solar, plus drives, rectifiers and non-linear UPS, push harmonic levels up.
Unifies correction, filtering and voltage stabilisation across multiple boards or sites — valuable for sensitive loads in hospitals, data halls and process plants on a fragile grid, with the visibility to prove power factor, reactive energy and kVA demand at the meter, continuously.
Why not just install capacitor banks? + Read more− Close
Switched-capacitor banks correct power factor in fixed steps at the incoming feed — enough, in theory, to lift you over the 0.96 threshold at the meter. But they respond in steps and seconds, so they lag fast-changing loads; they sit only at the boundary, so reactive current still flows through your internal network; and on a system carrying harmonics — as nearly every modern South African site now does, with its solar inverters, drives and rectifiers — a capacitor bank can form a resonant circuit with the supply, amplifying those harmonics rather than removing them.
HarmoniQ is solid-state and dynamic: it corrects continuously rather than in steps, works across the network rather than at one point, and carries no resonance risk. Paired with active filtering, it is power factor correction and harmonic mitigation designed for a plant full of inverters and drives, not the switchgear of forty years ago.
What It’s Worth
| Lever | What changes | Effect on the bill |
|---|---|---|
| Power factor → 0.98+ | Reactive energy and kVA maximum demand fall | Clears Eskom’s sub-0.96 reactive charge; cuts the kVA demand charge |
| Harmonic filtering to NRS 048-2 | Lower distortion, cleaner solar coupling, cooler transformers & cables | Lower losses, longer asset life, compliant supply |
| Capacity release | ~15–20% of transformer / switchgear headroom freed | Defer or avoid a costly Eskom or municipal connection upgrade |
| Indicative annual saving | A meaningful recurring saving in rand on a site of this size — growing with every annual tariff increase — plus the capacity released | |
Every site’s loads, tariff and reactive profile are different, and the figures above are illustrative of the mechanism — not a quote. Our engineers will model the exact power factor improvement, the reactive and kVA maximum-demand charges avoided, the losses recovered and the capacity released for your specific connection, in rand — get in touch for a site assessment, or see the method on our power factor correction and demand-charge pages.