Get green power step by step

Given the power required to cook food, heat water and run household appliances, it would be extremely expensive to convert a typical electricity-dependent home to a wholly photovoltaic (solar) system, even if a 50% reduction in the cost of PV panels is achieved soon.

That's according to Dr John Ledger, chairman of the Sustainable Energy Society of Southern Africa, who says homeowners should rather start introducing a mix of alternative energy technologies to wean themselves gradually off total dependence on mains electricity.

This will, over time, make them resilient to power outages as the demands on SA's electricity supply increase, reduce their electricity bills, and benefit the environment.

Writing in the Endangered Wildlife magazine, Dr Ledger says the best place to start is with a 2sqm solar water heater which will replace 2000KwH of electricity every year. It will also save 1000kg of coal and 2600L of water every year, and prevent the production of 1800kg of carbon dioxide, 284kg of ash, 16,4kg of sulphur dioxide and 7,2kg of nitrous oxide.

"The next area to look at is cooking, because an electric stove is a huge consumer of electricity. A gas stove provides instantaneous heat, and while not inexpensive, it does make you independent of mains electricity. Solar cookers and energy-efficient biomass cookers are also worth considering."

He says that to obtain renewable electricity in your home to provide power for your lights, your computer and your TV, you should start off with a set of batteries and an inverter that converts direct current from the batteries to the 220 volt AC that is used in the home. Then match this system to the power requirements of the lights and electronic equipment and feed the appropriate circuits.

"Initially, you can charge this battery set from the mains, which will make you independent of short-term power cuts, but in time you can add some solar panels, perhaps a small wind turbine if you live in a windy area, or some other way of charging your battery set, to enhance your independence from the municipality or Eskom."

*For more information on sustainable energy, visit www.sessa.org.za