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Dave Smith

30 Mar 2019

With much more load-shedding still to be endured before the national utility can recover from the darkness over a long period of time, no one can afford to ignore this serious risk to business continuity. Most companies have already put measures in place to keep running when the power goes down, but it’s worth taking a fresh look at the options now that ‘no power’ has become the normal modus operandi when the national grid is constrained rather than a momentary blip.

The bare essential for survival today is a diesel generator large enough to keep the crucial equipment in an office or factory running when the power goes down. But there are a few fatal seconds after the electricity cuts off before a generator kicks in, and those are critical moments for sensitive equipment. That makes an uninterruptible power supply (UPS) system essential, to carry the load instantaneously until the generator takes over. The national electricity utility’s sustained load shedding is prompting some companies to request UPS systems sufficiently powerful and with the required battery capacity to run their equipment for the full four hours duration of the supply interruption. But that is rarely financially viable due to the cost of the energy storage batteries the UPS would need, making a generator essential.

Solar photovoltaic (PV) power is the best way to reduce your energy consumption import from the grid and cut the diesel bill when you run a standby generator during grid supply interruptions. Jasco’s Power and Renewable Energy division has turned the company headquarters in Midrand into a working model of solar power, with the carport roof covered with solar PV panels. On sunny days Jasco operates with very little energy imported from the grid, and on weekends the surplus power being generated is exported into the grid to boost City Power’s supply.

Embedded solar PV power has slashed Jasco’s enormous electricity bill by 33% and will pay for itself in five years. Or faster, if electricity tariffs rise at rates higher than originally projected. The downside is that grid-tied solar PV panel solutions need grid electricity reference voltage to generate energy. The solar PV panels generate direct current (DC) electricity, but commercial and industrial buildings operate on alternate current (AC) electricity, so the DC power is converted to AC by an inverter. In a power cut the inverter suspends operation and so does the solar PV power output (to ensure the safety of grid repair personnel). But it picks up again when the standby generator starts, and then reduces the amount of diesel you consume by supplying solar energy.

Jasco is also installing hybrid solutions for some customers, where solar energy is stored in large batteries for use when there is no sun, or no grid supplied power. But these batteries and associated equipment are expensive (even though the cost is reducing on a consistent basis), making these solutions unaffordable for the majority of smaller businesses or residential customers. However, as demand rises for these energy storage batteries the manufacturing costs will fall. That could soon make it viable for businesses to run on batteries, especially in areas where electricity tariffs fluctuate per hour and rise dramatically during peak business hours. A business could recharge its batteries during off-peak periods in the night from the grid when electricity is cheaper, then displace the grid and run on battery power during the peak periods during the day and early evening.

Until that becomes more economically viable, the best solution for surviving the blackouts is a UPS for instant backup, generators to keep the business running, and solar PV power to reduce your reliance on the grid for all energy consumed. From my experience of working in this electricity supply sector for some 20 years, I know there is no quick fix to the national grid supply problems we are currently experiencing.

The majority of Eskom’s power generation infrastructure is more than 40 years old. Fixing that up to eke out perhaps another 10 years of useful and highly beneficial economic life will be very expensive, hugely complex and require a large volume of highly skilled individuals. South Africa remains far too reliant on fossil fuels and desperately needs alternative energy sources, yet the government provides little incentive to invest in alternative renewable energy power generation. Just how badly served we are by distributed or embedded solar power is starkly illustrated by one simple comparison: Sunny South Africa enjoys (on average) the equivalent of 2,000 kilowatt hours (kWh) of sunshine energy a year for every square meter of land. Germany has far less sunshine at about 1,100 kWh of energy per square metre. Yet it has far more political will and generates as much power from solar alone in a year as the total generation capacity of the national utility.

The future lies with sunshine: acquire a grid-tie solar PV solution to save your business significant energy costs amidst near double digit grid tariff increases. Furthermore, install a UPS to protect your mission-critical business equipment and a standby generator, too.

Dave Smith is the Managing Director of Jasco Renewable Energy


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