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'Powering off' the Eskom grid: Suggestions for energy self-sufficiency

Load shedding, load reduction, and power outages reflect the 'heart of darkness' of a government that has plunged South Africa into a deep economic and social mess through systemic dysfunction and failure to govern.
'Powering off' the Eskom grid: Suggestions for energy self-sufficiency

On top of the coronavirus pandemic, the persistent power failure is exacerbating already dire unemployment in South Africa. The successive years of mismanagement, corruption, and incompetence revealed at the Zondo Commission have 'junked' our economy, hobbled our once functioning state-owned enterprises, accelerated economic decline, and now threatens dozens of patients' lives in Gauteng hospitals due to power outage damage at water reservoir pumps.

It's impossible to quantify the exact costs of power failures on the economy - business failure, loss of manhours and breakdowns of appliances. However, the SMME sector is most vulnerable to power failure economic distress, which places the sustainability of our country at significant risk. The SA Quarterly Labour Force Survey (QLFS) in the first quarter of 2021 gives the official unemployment rate as 32.6%, of which a significant segment is the youth. It's not surprising, therefore, that a report by risk assessment agency Eunomix Business and Economics Ltd (10 September 2020, in BusinessTech) predicted that South Africa would face significant economic decline and, ultimately, by 2030 rank the same as Bangladesh.

With Eskom CEO André de Ruyter acknowledging persistent 'load shedding' for the foreseeable future, South Africans have one of two choices: live with the inconvenience or go it alone and invest in an alternative backup system.

Below is an example of a tested solar model. The solar solution is purely for illustrative purposes and not to endorse any particular approach. Each household's needs and budget will be different and will require research for an appropriate approach.

At the outset, solar is probably the most accessible form of alternative energy. However, there are some basic requirements, such as sufficient and unobstructed roof space, but ground mounting is also an option.

The first step is to complete an energy audit to determine daily average consumption and peaks (when most power is consumed). After an accurate consumption audit, the second step will be to determine the size and number of solar panels and the size of the inverter (to convert the direct current to an alternate current that is ready for home use). The third step is to consider how long the system is required to run during and outside of load shedding hours. Then, to acquire the appropriate number of batteries (for example, two 3.5kWh batteries supply 1kW of power for six to seven hours).

There are many inverter options available. Off-grid systems are primarily used where there is no grid connection and do not require a grid connection. However, it would be best if you had batteries and solar panels in your initial setup.

Grid-connected or grid-interactive inverters allow for a grid connection with batteries and solar panels. Batteries are required for any backup system with solar panels. If installed without solar panels, these systems do not provide any savings as you are simply using the grid to charge your batteries and then using this stored electricity during load shedding.

A third option is the more expensive hybrid inverters. This allows for more flexibility because a hybrid inverter can seamlessly blend electricity from multiple sources such as wind, solar, generator, batteries, and the national grid. Savings are, however, only achieved when adding solar panels. Hybrid and grid-connected inverters without batteries cannot operate during load shedding.

Although moving off the Eskom grid is enticing, initial investment costs can be daunting. For illustrative purposes, an outlay of approximately R200,000 could include an 8kW hybrid inverter, 24 x 455W Solar panels, 4 x 3.5kWh lithium batteries, installation, and sundries to complete the installation. Savings, however, will include monthly electricity costs, potentially reduced appliance damage costs and capital appreciation on the residential/commercial property.

A real-life case study using a similar system as above over 236 days generated just over 9,700 kWh equating to a saving of over R24,000 at an average rate of R2.50/kWh based on the City of Cape Town tariffs. This could ensure that the outlay is repaid within approximately eight years. Batteries and inverters should last for 10 years, with the inverter having a design life of over 15 years. The solar panels are also designed to last approximately 25 years while retaining 80% of their rated output.

However, with budgets stretched, affordability might be a hurdle. Personal savings, if available, might be an option because reduced electricity cost savings represents a return of over 12% per year, excluding any future tariff increases by the City or Eskom. Financing this through an access bond, where the interest rate is relatively lower at 8%, also makes financial sense. Solar and battery technologies are also becoming more affordable.

There are many benefits to 'powering off' the Eskom grid. Besides the medium- to long-term cost savings, the most important benefit is to delink from an erratic and carbon-inefficient system. With its coal-burning power stations, Eskom is currently one of the biggest culprits for carbon emissions in the world!

Therefore in the interim, consumers must try and minimise electricity consumption as much as possible. This should include replacing incandescent lights with low energy LED light, cooking on gas instead of an electric stove and replacing high-consumption fridges and freezers with AAA-rated appliances. Additional changes such as using inverter air conditioners and changing an electric geyser to run on a solar evacuated tube would contribute to the drastic decrease in energy consumption.

The solar alternative energy solution is shared as one of the options that consumers can explore to mitigate the impact of 'load shedding' or power failure on households.

More importantly, sharing the information is part of TSIBA Business School's mission of presenting knowledge value in a practical way whilst striving towards social and planetary sustainability.

14 Jun 2021 17:16


About the author

Achmat Kazie, BA(SA), GTP(SA) and Rudi Kimmie (PhD) are from the TSIBA Business School. They write in their personal capacities.

TSIBA Education trading as TSIBA Business School is registered as a non-profit and public benefit organization with the Department of Higher Education and Training as a private higher education institution under the Higher Education Act, 1997. (Registration certificate no. 2007/HE08/001)