AS ESKOM’S crippling load-shedding programme entered its second week last week, the search for alternative power supplies gained urgent momentum, with solar power and generators the most talked-about options. “We are completely inundated with inquiries asking about solar panels,” said Uwe Klingenber of KG Electric, supplier of solar and wind power solutions. “But in response to the current power situation, solar panels are not the answer.” And the reason is not because of the weather. “It’s just too expensive,” said Klingenber. “It would be ludicrous to use a solar-powered setup as a backup when the power dies.” Assuming the monthly usage is 1400 kW-hrs (R700 Eskom bill at typically 50c per kW-hr) a solar system to meet this usage would cost well in excess of R700 000 for the main equipment alone, excluding VAT. “If you are looking for a backup option, rather go for a battery bank together with an inverter/charger unit,” says Klingenber. When the mains are available this unit acts as a charger, charging the battery bank. During a power outage the unit acts as an inverter – it converts DC battery power to 220V AC power. A typical system with an inverter will cost around R18000 excluding VAT. This, with ten batteries totalling R8000, will provide about 8000Watt-hours of electricity backup. “From here it all depends on your load usage. With this set-up you could get about five hours at 1600W average power output, or with 400W usage you would then get 20 hours of backup.” Once depleted, the batteries will then need 10-12 hours on the mains to recharge the battery bank. “For all its noise, a diesel generator is going to be the cheapest option to keep your systems online,” adds Klingenber.
