Tesla has finally arrived in South Africa, even if in a somewhat unexpected guise. With the availability of the US company’s electric cars apparently still some way off, South Africans do, however, now have access to its energy storage solutions.

The stationary, rechargeable lithium-ion battery Powerwall offers an energy storage solution to the residential market, while the Powerpack is a commercial and utility energy storage solution.




The Powerwall stores electricity generated from solar panels for self-consumption, time of use load shifting and backup power. The larger Powerpack, intended for commercial or electric utility grid use, can be used for peak shaving, load shifting, backup power, demand response, microgrids, renewable power integration, frequency regulation and voltage control.

Both products entered the global market in 2015, launching onto the South African market in 2016.




Tesla, however, remains mum on its business here in South Africa, preferring that its customers do the talking.

40% OF ENERGY NEEDS

One of the first local clients for the Tesla Powerwall was self-confessed tech junkie Andreas Cambitsis.

Cambitsis is a director at the Business Science Corporation. He stays in Fourways, Johannesburg, and installed a Powerwall earlier this year for use by his household, consisting of five people.

His household’s energy consumption is higher than the average household given that it is a double storey house, with a pool and air conditioning.

The energy system is comprised of a 4.6 kW solar photovoltaic (PV) installation with energy harvested from 18 solar panels installed on the private residence’s roof, an inverter, and the Powerwall, which has a capacity to store 6.4 kWh.

“On average, the system produces around 40% of our energy needs,” says Cambitsis.

“On its best day to date, the solar PV system produced 28.9 kWh, which is more than 50% of our consumption.”

Performance is affected by the position of each solar panel, how long the days are, cloud cover, as well as household demand.

Cambitsis notes that for a 4.6 kW system to produce 28.9 kWh of energy “is extremely good”, and a prime indicator that the South African climate is “very conducive to solar energy production”.

Cambitsis can track the system’s operation with his smartphone, through an app that can even provide data on the individual performance of each solar panel.

Cambitsis’ decision to install the system was driven by a desire to leave a smaller carbon footprint, and to prove to himself and others that the technology works, paving the way for a future of energy self-generation.

These same factors motivated him to drive a BMW i3 electric car. (For those who are curious, charging the i3 demands around 10% of the Cambitsis household’s total power needs.)

Driving around 100 km a day, Cambitsis pays roughly R10 for his daily commute, at existing electricity and fuel prices.

The price tag of Cambitsis’ solar system was around R230 000 for the battery, inverter, solar panels and installation costs. The Powerwall itself made up around one-third of this number.

Whilst Cambitsis says he does not expect the system to pay for itself over the ten-year warranty of the battery, his net pay-in over this period is expected to be less than R80 000, given that the 40% monthly saving on his electricity bill will contribute to a recovery of at least R150 000 over the 10 years.

That said, he believes the money is worth it when considering the benefits. Having backup power and greater grid independence is certainly a motivator, in addition to the environmental benefits.

Cambitsis also installed LED lights throughout his home, cutting his electricity bill by another 20%.

POWERWALL 2

Cambitsis says he has been considering going solar for a while, but had difficulty justifying the decision.

“The biggest issue with solar is the mismatch between when electricity is generated and when the consumption is needed. In the absence of being able to feed back into the grid, you need storage.

“Prior to the Powerwall this was a real pain as the solution typically involves a stack of deep cycle lead-acid batteries that take up significant space, are unattractive and complex to install and operate. For those reasons I would never consider that solution. The Powerwall solves the aesthetics and space issue and is a simpler and more integrated solution with the inverter than the traditional approach.”

Cambitsis believes the Powerwall 2 will provide significantly more financial benefit.

“Powerwall 2 will be a significant upgrade. Capacity will be double at around 14 kWh – with an integrated AC inverter – but only a 50% increase in cost,” says Cambitsis.

“In two years, as Eskom increases its tariffs and hardware costs continue to decline, it will be a no-brainer to have a Powerwall.”

Cambitsis believes a Powerwall 2, coupled with a few more solar panels, will be able to supply 80% of his household’s energy needs.

With its increased capacity, the Powerwall 2 will provide a guaranteed backup of six or more hours, as opposed to the Powerwall 1, which he views as a more limited backup solution.

But has it only been a positive experience to buy and install the combined solar and Powerwall system in his home?

Cambitsis says while he is “very pleased” with the system’s performance, he believes the buying experience has room for improvement.

“I believe the process can be made more customer friendly in providing more information and tools on what type of system can best match your personal circumstances. Currently you have to do a lot of research yourself to figure out all the tradeoffs that are best for your circumstances. I think that as the South African renewable energy sector improves in this area, it will help drive the adoption of solar systems.”