Dancing in the dark

In January this year almost the entire country suffered from what the electricity generating utility, Eskom, euphemistically called “load shedding”. Whole suburbs were disconnected from the grid (so no mains power) for 2-3 hours at a time. In my municipality, Sandton, this was happening as many as three times a day, although reports were that this was one of the worst affected areas.

The explanation that we were given by the government was that unprecedented economic growth had resulted in electricity demand outstripping supply. However it soon emerged that the 1998 Energy Policy White Paper, a government document, warned that the reserve margin would be insufficient by 2007 unless additional electricity generation capacity was added. However due to policy uncertainty resulting from a failed initiative to privatize electricity generation, the incompetence of the responsible cabinet ministers, and the failure of Eskom management to draw public attention to the impending gloom, nothing was done about it. So right on schedule, at the end of 2007 and beginning of 2008, demand outstripped supply due to a combination of planned and unplanned maintenance which exceeded the reserve margin.

Horror of horrors, the power cuts did not only occur during the week, when I work, but also on weekends, when I contest. The prospect of six or eight hours of enforced radio silence during a major contest was enough to spur me into action, so I installed an Uninterruptable Power Supply (UPS) system. The UPS consists of a battery charge, a bank of six 100 A-hr lead-acid batteries, and an inverter to generate mains voltage (230 V 50 Hz) from the batteries when the mains supply is off. I cabled up power sockets around the house so that essential equipment like the refrigerator, alarm system, television, computer and of course the entire shack can be run off UPS power. I also installed a few neon tube emergency lights on the UPS circuit.

UPS

The UPS system sits on top of a home built battery cabinet. Its output is connected via the red socket to a small distribution board, which I included primarily to have earth leakage protection in the UPS circuit. The white socket on the left is one of the seven around the house to provide emergency power for appliances. The small 18W neon light at the top is one of several around the house that are also connected to UPS power. The UPS can provide 2400 kVA peak (enough to run the microwave, fridge and television simultaneously), and has sufficient storage capacity to supply an average power of 500 W for 8-10 hours.

I have also installed energy efficient lighting, replacing 50W downlights with Osram Decostar IRC 35W halogen bulbs and incandescent bulbs with compact fluorescents wherever possible. I’ve also set the pool pump timer to run from during off-peak times, from 8pm to 6am. However this may be self-defeating since the timer is itself mains powered so any load-shedding will “time shift” it back towards peak hours….

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