Goodbye Eskom — The truth about going off-grid

The severe load-shedding that South Africa has endured in the past few months has many more households threatening to go entirely off-grid, but the reality is that kicking Eskom to the curb is no simple or cheap endeavour.

Christiaan Hattingh, managing director at solar systems provider AWPower, told MyBroadband the company had observed some interesting trends following the September re-emergence of stage 6 load-shedding.

Hattingh said fewer people were buying backup power solutions as “grudge purchases” out of impulsive anger over load-shedding.

Instead, many of the more calculated planners had realised load-shedding would remain a reality for the foreseeable future and were pulling the trigger on self-generation.

But Hattingh has maintained his previous stance that going totally off-grid was simply out of reach for most households.

“In our experience, specifying solar panels, generators, and battery storage that provide complete grid independence is too expensive to be practical for most small businesses or homes,” he explained.

Oversizing is the name of the game

The cost is prohibitive because going completely off-grid requires an oversized system to compensate for the fluctuation in solar availability, even in a country with plenty of sunshine.

During prolonged periods of cloud cover, especially problematic during Cape Town’s winters or days-long thunderstorm activity in the northern parts of the country, solar efficiency can dip as low as 15%.

“Off-grid means you have to spec for the worst-case scenario, unless you have an alternative like a generator to cover that shortfall,” Hattingh said. “Whatever you think you need — you need more than double, triple, quadruple.”

If you are dead set on saying goodbye to Eskom, you can expect to spend around R700,000 to power a home with around 1,200kWh of monthly usage with full self-generation.

But if you are willing to get only 2-5% of your power from Eskom, that cost decreases dramatically.

However, Hattingh said giving an average figure of how much a semi-off-grid system would cost was complicated, as there were many variables to consider.

The number of rooms or residents in a house does not directly translate into higher overall usage, because several energy-conscious users can live off much less electricity than a handful of electricity wasters.

Hattingh previously provided a rough cost breakdown to show how much it could theoretically cost households with 600kWh, 900kWh, and 1,200kWh of usage to go semi-off-grid.

Semi-off-grid backup power options
Average monthly usage 600 kWh 900 kWh 1,200 kWh
Phase  Single-phase  Single-phase Single-phase
Inverter  1 x 5kW Deye Hybrid Inverter  1 x 5kW Deye Hybrid Inverter  1 x 8kW Deye Hybrid Inverter 
Battery
  • 1 x 5.12kWh Revov R100 Li-Ion Battery  (5.12kWh @ 100%)  or
  • 1 x 7.4kWh SolarMD Advanced Li-Ion Battery (7.4kWh @ 100%)
  • 2 x 5.12kWh Revov R100 Li-Ion Battery (10.24kWh @ 100%) or
  • 1 x 14kWh SolarMD Advanced Li-Ion Battery (14kWh @ 100%)
  • 1 x 14kWh SolarMD Advanced Li-Ion Battery (14kWh @ 100%)  or
  • 3 x 5.12kWh Revov R100 Li-Ion Battery (15.36kWh @ 100%)
Excluded from cost estimate Additional load-splitting, if necessary Additional load-splitting, if necessary Additional load-splitting, if necessary
PV panel array size  4.14kWp (9 x 460W panels)  6.44kWp (14 x 460W panels) 8.28kWp (18 x 460W panels)
Est. electricity savings p per month  R1,368* R2,401* R3,283*
Payback period   6.7 – 7.2 years  5.7 – 5.9 years 5.2 – 5.5 years
Total system cost (incl. VAT) R138,481 – R152 124  R196,977 – R207,439 R241,713 – R257,529
Estimated % of energy requirements from grid and own generation Own generation — 95%

Eskom grid — 5%

Own generation — 98%

Eskom grid — 2%

Own generation — 95%

Eskom grid — 5%

* Based on standard City of Cape Town home user tariff of R2.40/kWh for first 600kWh and R3.31/kWh above 600kWh. Annual tariffs increase of 9.06% is assumed for payback period calculation.

Hattingh advised potential buyers to conduct thorough research and take their time when consulting with an accredited service provider to ensure they get the most cost-effective system tailored to their requirements.

As part of this, he emphasised it was essential to properly understand your consumption habits first.

Going off-grid is much easier and cheaper for those willing to adapt their habits instead of keeping their consumption levels the same as when relying on Eskom.

If you are willing to sacrifice and use certain high-demand appliances only at specific times of the day, some households could get by on a smaller setup.

Second-life batteries can help you save on energy storage

In addition, Hattingh said another way to cut costs on storage was to use second-life lithium-iron phosphate batteries — like those from Revov.

These are refurbished and repurposed units made up of cells taken from electric vehicles that have reached their end-of-life after a typical five-year period.

These batteries come with effectively the same warranty and capacity — up to 10 years and 3,500 cycles — as brand-new units, while costing less.

These batteries can still offer good value because the chemical makeup of lithium-ion cells allows them to last up to 25 years in certain circumstances.

Hattingh also provided the names of several brands of inverters, batteries, and solar panels that customers should consider as reliable options for off-grid and grid-tied solar-and-backup systems, listed in the table below.

Recommended brands
Solar panels Inverters Batteries
Canadian Solar
Jinko Solar
JS Solar
Longi
Apex/Apex
Axpert (includes some Kodak, Mecer, and RCT models)
Deye
Victron
Sunsynk
Freedom Won
Revov
Solar MD

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Goodbye Eskom — The truth about going off-grid