With a national blackout looming, electricity users are cursing Eskom in the darkness.
Load shedding means no internet, no hot showers and no TV. Garage doors barricade us in (or out of) our own homes.
Generators are the obvious first port of call. However, to the typical consumer, this alternative energy source is often synonymous with a lot of noise and a lot of money.
With that in mind, Moneyweb set out to find the ideal household solution.
“Small household generators are not too expensive from a capital point of view but are expensive to run,” says Paul Tuson, chief electrical engineer of engineering and development consultancy Mott MacDonald in Johannesburg.
The type of generator depends largely on individual usage needs.
www.ipowersa.co.za offers a free usage calculator. To run ten (power-saving) lightbulbs, a fridge-freezer combination, your security alarm, a television with satellite decoder, an electric gate or garage door and two cellphone chargers will require roughly 3 kilowatts (kW). A 3kW Stramm petrol generator sells for R4 200 at Game.
This particular generator weighs about 40kg (excluding the weight of the petrol), has a 15-litre tank, and will run for about two to three hours at full capacity. Thanks to the recent petrol price decline, this comes to R165 per tank. If you experience three-hour blackouts twice a week, your monthly petrol bill will be in the region of R1 350.
“Anything that heats or turns is bad news,” warns Tuson. If you want to run your geyser, stove, kettle, heaters and pool pump, you’re looking at a bigger investment.
This generator emits a sound of 72 decibels (dB), equivalent to the sound of highway traffic at a range of 20 metres. “Distance and walls are good attenuators of sound,” says Tuson. Try put your generator outside and as far as possible from the house.
The noise is loud enough to prohibit you from running your generator at unreasonable hours. You could attempt to muffle the sound by building a “brick kennel,” but this needs to be properly ventilated to allow petrol fumes and combustion emissions to escape.
“You can’t just run a generator parallel to the main board,” says Tuson. “When utility power comes back on (from Eskom or your municipality), your generator could be out of phase with the grid power, and might get damaged.”
Moreover, there is stringent legislation governing small-scale parallel generation connections.
To connect your generator to the main circuit board requires a bypass switch. Tuson recommends that you ask a certified electrician to install one. An estimate of this cost is R2 000. A buzzer can be installed on the “mains” (utility) side of the by-pass switch to indicate to the householder when utility power returns.
Alternatively, items can be connected directly to the generator via an extension cord, although you must ensure that they are “islanded” (disconnected from the main electrical distribution board). This method requires no installation by an electrician, but only allows you to use smaller appliances such as cellphone and laptop chargers and won’t power your main system lights or heavier appliances.
Smaller generators, such as the 750-Watt Stramm generator, available at Game for R1299, will power a few chargers and at most a TV set.
Generators of a larger capacity are also available. For R20 000, a 7.6kW generator – with a 25-litre tank, weighing in at 161kg and emitting 77dB (the sound of an aeroplane 1.5km away) – from Gemini Small Engine Service will allow you to run the same appliances as the 3kW generator, as well as a stove, oven and geyser.
For those looking to support their entire usage with a generator, prepare to cough up. A typical household would need 16-17kW. A heavy-duty 17kW Kipor generator sells for R90 800 at Simkul, and comes with a mammoth fuel bill.
The table below summarises the generator findings:
|Stramm||750W||R1 299||10 lights, TV, decoder, home alarm, 3 chargers, desktop computer||Game|
|Stramm||3kW||R4 200||10 lights, TV, decoder, home alarm, 3 chargers, desktop computer, fridge kettle||Game|
|Ryobi||5,5kW||R7 490||10 lights, TV, decoder, home alarm, 3 chargers, desktop computer, fridge kettle, stove OR microwave||Game|
|Kipor||7,6kW||R19 990||10 lights, TV, decoder, home alarm, 3 chargers, desktop computer, fridge kettle, stove OR microwave, oven, geyser.||Gemini Small Engine Service|
|Kipor||17kW||R90 800||Most common household appliances (including pool pump)||Simkul|
For now, complete off-grid household support is impractically expensive. The 3kW generator – for R6 200 including installation, and R1 350 per month in petrol costs – will power your Wi-Fi router, charge your laptop, keep your food fresh and allow you to get out of your gate. It’s a practical and balanced solution that won’t cause you to bend over backwards financially.