Electric versus petrol cars — Eskom’s proposed power tariffs will make you want to switch

South African motorists would shave hundreds or thousands of rands per month from car running costs if they could switch to an electric vehicle (EV) under Eskom’s proposed new power tariff plan.

That is according to an analysis of the costs to charge various EVs with the new tariffs compared to filling up the most fuel-efficient petrol, diesel, and hybrid cars in South Africa.

South Africans tend to be highly sceptical of EVs, which is no surprise given the frequency of load-shedding that could make it difficult to charge your car as and when you please.

But EVs can add relatively large amounts of range every hour they are charged.

In stage 4 load-shedding, you stand to be without power for up to six hours per 24-hour cycle, with a maximum of four falling within the 12-hour period that you might be home.

That would leave you with at least eight hours to charge your car at home, which is plenty of time to top up most EV batteries for a typical commute.

Rapid public chargers also allow for charging at much faster speeds if you need a quick refill— provided you are willing to pay a premium over your home electricity charges.

Another feature to consider is that some electric cars can provide backup power to your home during load-shedding.

That includes Kia’s EV6 electric crossover, which is confirmed to be coming to South Africa.

Its vehicle-to-load (V2L) capability gives you a power output of up to 3.6kW and either 58kWh or 77.4kWh of capacity, equal to multiple Tesla Powerwalls.

Other electric vehicles that support this feature include Ford’s F-150 Lightning and the Fisker Ocean.

The Ford F-150 Lightning’s power output sockets are enough to support some power tools

Many have also raised concerns over the potential impact of EV charging on Eskom’s grid.

Eskom told MyBroadband it had factored EV adoption into its future projections for growth in demand.

“The Integrated Resource Plan (IRP) 2019 projected the influence of EVs to be minimal in the IRP window up to 2030 and indicated that future IRP will include a scenario to test the penetration of EVs,” the utility said.

“Although EV sales might increase, there are a number of sectors aiming for higher electrification applications, and therefore EVs will form part of the forecast and not be treated in isolation.”

Eskom has also recently submitted a new tariff plan to Nersa seeking to revamp how South Africa’s electricity tariffs are calculated.

While it introduces additional fixed capacity costs, it also does away with the Incline Block Tariff (IBT).

The result is the price per kWh of electricity gets cheaper for the average and above-average consumer.

Naturally, people who acquire electric cars will use more electricity than before to charge them, so the tariff change will likely benefit them.

Time-of-use tariff

Furthermore, Eskom is proposing a residential time-of-use tariff called Homeflex, which will be optional for all Eskom-connected customers and could bring additional benefits if you time your car charging well.

Eskom said this tariff would provide the correct pricing signal for EV charging and usage depending on the hour that batteries are charged.

“So if charged in off-peak hours, these charging costs will be at a much lower rate than the tariff rate in a peak hour,” Eskom said.

“This also greatly incentivises the use of alternative energy sources to also charge EV batteries.”

One of Eskom’s proposed time-of-use tariffs, dubbed Homeflex 4, is detailed in the table below.

Eskom proposed Homeflex 4 tariffs
September to May (low demand) Times June to August (high demand) Times
Standard tariff R1.04 Weekdays: 08:00—17:00 and 20:00—22:00
Saturdays: 07:00—11:00 and 18:00 to 20:00
Sundays: 18:00 to 20:00
R1.10 Weekdays: 08:00—17:00 and 20:00—22:00
Saturdays: 07:00—11:00 and 18:00 to 20:00
Sundays: 18:00 to 20:00
Peak tariff R1.77 Weekdays: 07:00—09:00 and 17:00—20:00 R4.11 Weekdays: 06:00—08:00 and 17:00—20:00
Off-peak tariff R0.77 Weekdays: 00:00—06:00 and 22:00 to 00:00
Saturdays: 00:00—07:00, 12:00—17:00 and 20:00—00:00
Sundays: 00:00—18:00 and 20:00—00:00
R0.77 Weekdays: 17:00—20:00
Saturdays: 00:00—07:00, 12:00—17:00 and 20:00—00:00
Sundays: 00:00—17:00 and 19:00—00:00

We calculated how much it would cost to recharge an EV under Eskom’s Homeflex 4 and fixed Homepower 4 tariffs.

We then compared the cost per kilometre for a fully-charged electric vehicle to that of various fuel-efficient petrol, diesel, and hybrid cars.

In most scenarios, whether with Homeflex 4 or the non-time-of-use Homepower 4 tariff, electric vehicles were much more cost-effective than fossil-fuel-based cars.

The only exception was the e-Tron which cost slightly more per kilometre to fill during the winter peak than the most fuel-efficient car — the Toyota Corolla Hybrid.

For example, filling up the EV6’s larger 77.4kWh battery from 0-100% would cost just R59.92 if you only charge it overnight on the off-peak tariff during the winter and summer.

With the EV6 with this battery offering a WLTP range of 528km, it works out to roughly 11 cents per kilometre when only using off-peak electricity.

If you charge only with the standard tariff during the summer, a complete refill will cost R80.60, while doing the same during the winter will cost R85.77, working out to 15 cents and 16 cents, respectively.

Even when charging during the most expensive peak hours of winter, the cost per kilometre worked out to 60 cents — cheaper than the 82 cents to R1.28 the petrol, diesel, and hybrid cars would cost.

Refuelling and refilling cost comparison
Model Full tank/charge cost Maximum range Cost per kilometre
Unleaded 95 Petrol for R23.38 per litre / 50ppm diesel for R24.15
Fiat 500 Dolcevita (best petrol) R818.30 875km R0.93
Mahindra KUV 100 (best diesel) R845.25 795km R1.06
Toyota Corolla Hybrid XS (best non-plug-in hybrid) R1,005.34 1,229km R0.82
Kia Sonet Turbo 1.0 (comparable Kia crossover) R1,052.10 819km R1.28
Summer and Winter Off-peak — R0.77 per kWh
Audi e-tron Quattro Advanced (95kWh) R73.54 441km R0.17
BMW iX xDrive50 (111.5kWh) R86.32 630km R0.14
Kia EV6 (77.4kWh) R59.92 528km R0.11
Summer Standard — R1.04 per kWh
Audi e-tron Quattro Advanced (111.5kWh) R98.93 441km R0.22
BMW iX xDrive50 (111.5kWh) R116.10 630km R0.18
Kia EV6 (77.4kWh) R80.60 528km R0.15
Winter Standard — R1.10 per kWh
Audi e-tron Quattro Advanced (111.5kWh) R105.27 441km R0.24
BMW iX xDrive50 (111.5kWh) R123.56 630km R0.20
Kia EV6 (77.4kWh) R85.77 528km R0.16
Summer Peak — R1.77 per kWh
Audi e-tron Quattro Advanced (111.5kWh) R168.10 441km R0.38
BMW iX xDrive50 (111.5kWh) R197.30 630km R0.31
Kia EV6 (77.4kWh) R136.96 528km R0.26
Winter Peak — R4.11 per kWh
Audi e-tron Quattro Advanced (111.5kWh) R390.85 441km R0.88
BMW iX xDrive50 (111.5kWh) R458.74 630km R0.73
Kia EV6 (77.4kWh) R318.44 528km R0.60
Homepower 4 (no time-of-use) — R1.56 per kWh
Audi e-tron Quattro Advanced (111.5kWh) R148.09 441km R0.35
BMW iX xDrive50 (111.5kWh) R173.81 630km R0.27
Kia EV6 (77.4kWh) R120.65 528km R0.23

Another part of Eskom’s power tariff plan could see EVs help their owners reduce their electricity bill.

Eskom has proposed introducing a net-billing mechanism, which will credit customers the electricity they feed back into the grid at the same rate they are charged.

While ideal for those with solar-power systems, it is also possible to install vehicle-to-grid equipment to feed electricity from your car’s battery into Eskom’s network.

If you still have some charge to spare when you arrive home from work, you can feed power back into the grid during peak hours for a net-billing gain.

Now read: Load-shedding traffic nightmare — why batteries for robots don’t work

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Electric versus petrol cars — Eskom’s proposed power tariffs will make you want to switch