Your July bill is on the desk. The packhouse ran the same hours as last month. Nothing broke. Nobody new started.
The bill is bigger anyway.
The reason is on the rate page. Almost nobody reads the rate page.
It isn’t load shedding. It isn’t the April increase either. That landed months ago.
It’s when you use the power.
What the Ruraflex tariff charges you this winter
Ruraflex is a time-of-use tariff. The same unit of power costs different money at different hours.
Think of the petrol price moving through the day. Same fuel. Different money out of your pocket.
In winter, a unit taken in a peak block costs you 732.98 c/kWh. Overnight, the same unit costs 122.16 c/kWh.
610.82 c/kWh
The winter gap between peak and off-peak on Ruraflex, excluding VAT. About R6.11 on every unit you shift out of the peak. It is the widest gap Eskom publishes on any main tariff — wider than Megaflex, at 600.16 c/kWh.
Most packhouses, dairies and cold stores on Ruraflex have never seen that number.
One check first. Ruraflex is an Eskom-direct tariff. If Eskom sends your bill, these rates are yours. If a municipality sends it, they are not, and your rise landed on 1 July.
Rates below: non-local-authority, ≥500 V and ≤22 kV, within 300 km of the transmission zone. Excluding VAT.
Winter weekdays have two peak blocks. One starts around 06:00, one around 17:00. Each runs about two hours. Check Appendix A, Figure 2 of the Schedule for your times.
So a battery has to cover two hours, twice a weekday. That sets the kWh. The depth of the bite sets the kW. We worked that through in our 1 MWh versus 500 kWh comparison.
Two Ruraflex charges that don’t behave like Megaflex
This is where most Ruraflex proposals go wrong.
The network demand charge doesn’t care when you use power
On Megaflex, the network demand charge is R26.29/kVA/month. It is billed on chargeable demand — your biggest gulp of power in the peak and standard hours. Shave the peak and it falls.
Ruraflex works differently. There is no kVA demand charge at all. Instead there is 45.56 c/kWh, and it lands in every period.
Move a unit from peak into off-peak and you still pay 45.56 c on it. Only using less power brings it down.
If a vendor’s Ruraflex model shows a demand saving in R/kVA/month, ask which line of the Schedule it comes from. There isn’t one. There is a network capacity charge in R/kVA/month. But that follows the capacity you use all year, not your monthly peak.
So we leave it out of the sums below. It costs you only on the losses.
Rural capacity costs more than urban
Ruraflex network capacity is R52.55/kVA/month excluding VAT. On the urban tariffs the same charge is R39.13. That is 34.3% higher.
Per 100 kVA that is R63,060 a year (R52.55 × 12 × 100). An urban site pays R46,956. You pay R16,104 more, for sitting at the end of a rural line.
So “right-sized” means something different out here. Every kVA you carry costs you all year, used or not.
Size the connection to your base load. Cover the short, sharp peaks with storage. One caveat: the saving has to hold all year. One good month won’t help you.
What one shifted unit is actually worth
Here is the arithmetic, every assumption on the table. These are our modelling inputs, not facts about your site.
Assumptions
- Ruraflex, non-local-authority, ≥500 V & ≤22 kV, ≤300 km — rates as published for 2026/27, excluding VAT
- The battery discharges into both weekday peak blocks. Total shifted: 1,000 kWh a day
- All recharging happens off-peak at 122.16 c/kWh
- Round-trip efficiency of 90% — how much comes back out against what went in. A Terawatt engineering assumption, not a published figure
- 22 operating weekdays a month
- The 45.56 c/kWh network demand charge, 24.57 c/kWh legacy charge and 0.45 c/kWh ancillary service charge apply in all periods. So they cancel out on shifted energy. They are charged only on the losses
Winter, per kWh delivered into the peak:
- To deliver 1 kWh at 90%, you buy 1 ÷ 0.90 = 1.1111 kWh off-peak
- Peak energy avoided: 732.98 c
- Off-peak energy bought: 1.1111 × 122.16 = 135.73 c
- Charges on the 0.1111 kWh of losses: 0.1111 × (45.56 + 24.57 + 0.45) = 7.84 c
- 732.98 − 135.73 − 7.84 = 589.40 c/kWh. Call it R5.89 a unit, excluding VAT.
At 1,000 kWh a day that is R5,894 a day. Across 22 weekdays, R129,669 a month.
Summer, same sums: 304.19 c avoided, less 135.73 c of recharge, less 7.84 c of losses = 160.61 c/kWh. That is R1.61 a unit, R1,606 a day, R35,335 a month.
Same battery. Same site. Same 1,000 kWh moved. The winter unit is worth 3.7 times the summer one.
The question that decides your business case
It isn’t “how big should the battery be”.
Does your processing season overlap June, July and August?
Farm load is rarely flat. Eskom’s winter season runs three months in twelve. A citrus packhouse, a maize mill and a dairy all run at different times.
Same system. Seven operating months either way:
- Season overlaps winter (3 winter + 4 summer months): (3 × R129,669) + (4 × R35,335) = R530,348 a year
- Summer-only season (7 summer months): 7 × R35,335 = R247,346 a year
A gap of R283,002 a year. Same steel. Same battery. 2.1 times the value, on calendar overlap alone.
Which is why we won’t quote a payback off a tariff name and a bill total.
Turning that into a payback without inventing a price
Payback is cost divided by yearly benefit. We gave you the bottom half. Your quote gives you the top half. So work it per million rand:
- Winter-overlapping season: R1,000,000 ÷ R530,348 = 1.89 years per R1m installed
- Summer-only season: R1,000,000 ÷ R247,346 = 4.04 years per R1m installed
Take your quoted price in millions and multiply.
That counts the load shift and nothing else. No diesel saved. No solar. No tax. Nothing for staying up when a rural transformer fails. It is the gloomy number on purpose. Our savings calculator gets you a first pass.
Where solar does something a battery can’t
A battery moves energy from one period to another. It captures the gap, nothing more.
Solar takes the unit off the bill for good. On Ruraflex that beats the headline rate. The c/kWh charges stack up.
A unit you make and use yourself in a winter standard hour avoids:
- Active energy, standard, winter: 183.23 c
- Network demand charge: 45.56 c
- Legacy charge: 24.57 c
- Ancillary service charge: 0.45 c
- Total avoided: 253.81 c/kWh excluding VAT
That is 38.5% more than the energy rate alone. In summer the same unit is worth 241.61 c.
Solar is also the only lever that touches the network demand charge.
So on Ruraflex the answer is usually solar and storage. Solar works on the whole stack through the day. Storage works on the 610.82 c winter gap, in the peak blocks solar can’t reach. Our guide to peak shaving covers the order.
On tax: there is a fast write-off for solar and storage assets. The rate and who qualifies depend on the asset. We have written about the incentive. Check it with your tax advisor before you model it into a payback.
Why next April matters more than this July
Eskom-direct customers took 8.76% on 1 April 2026. That number is padded. Here is why.
NERSA got Eskom’s regulatory asset base wrong by R54.7 billion. A High Court order forced public consultation. The regulator then chose to claw the error back over three years. That is R12 billion in 2026/27, R23 billion in 2027/28, and R19.7 billion after that.
The instalment you are absorbing now is the small one. It roughly doubles next April.
So a payback built on today’s rates is a cautious one. Every figure here is a floor. More in our Eskom tariff and load shedding forecast.
What to do this week
Three things. None need a supplier.
- Pull your last twelve bills. Mark the months your line actually ran. Do any land in June, July or August?
- Find the network capacity charge and check the kVA you are billed for. Do you need all of it, all year?
- Ask your meter provider for six months of interval data — your usage in half-hour blocks. Usually free.
An honest warning. If your season is all summer and your bill is small, a battery is probably not your first move. We would look at solar there, and say so.
Questions we get asked
Is Ruraflex better than Megaflex for a battery?
For shifting energy, slightly. The winter gap is 610.82 c/kWh against Megaflex’s 600.16 c/kWh — a difference of 10.66 c. On demand charges Megaflex wins. Its R26.29/kVA/month charge falls when you shave a peak. Ruraflex has nothing like it.
My season runs October to March. Is a battery still worth it?
Worth it, but over longer. Roughly 4.04 years per R1m installed on load shifting alone, against 1.89 for a winter season. We would look at solar first there. Solar value barely moves with the season. Load-shift value drops by two thirds.
Will peak shaving cut my Ruraflex capacity charge?
No. That charge is R52.55/kVA/month. It follows the capacity you use all year, not your monthly peak. Shaving a peak won’t move it. Cutting it means needing a smaller connection. That is a design decision, not an operating one.
My municipality bills me, not Eskom. Do these rates apply?
No. Ruraflex is an Eskom-direct tariff. If a municipality bills you, you are on their tariff, with their own peak hours. Your rise landed on 1 July, not 1 April. The method here still works. The numbers do not.
Get the number for your site, not a typical site
A blog post can’t tell you how much of your peak load will really move. That takes interval data and a site visit.
Often the answer is a smaller system, or solar first. We will tell you that.
Model it on your actual Ruraflex data
Send us six months of interval data and your latest Eskom bill. You get a load profile, a model built on the published rates, and a costed plan.
Tariff figures are Eskom’s published 2026/27 Schedule of Standard Prices, effective 1 April 2026, non-local-authority, ≥500 V and ≤22 kV, ≤300 km, excluding VAT. Round-trip efficiency, operating days and load-shift volumes are Terawatt modelling assumptions. Rates differ by voltage, distance and supply category — confirm yours against your own schedule.
