The following information has been taken from the Johannesburg City Website (www.joburg.org.za click on residents—tariffs)
City Power charge winter tariffs from May through August
Domestic 3 phase – energy (cents per kWh)
Current Proposed Increase
2011/12 2012/13
Summer Tariffs
0 – <500 kWh 83.18 93.99 13%
501 – <1000 kWh 84.47 95.45 13%
1001- <2000 kWh 85.76 96.91 13%
2001 – <3000 kWh 87.05 98.37 13%
Winter Tariffs
0 – <500 kWh 125.18 141.45 13%
501 – <1000 kWh 127.12 143.65 13%
1001- <2000 kWh 129.07 145.85 13%
2001 – <3000 kWh 131.01 148.04 13%
The above are stepped tariffs – you are charged according to the amount you use in each band.
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NORFED (Northern Federation Of Ratepayers) members have been advised by various market specialists in the energy field that we can expect load shedding shortly. Mr. Mike Schussler, a highly respected economist based in Johannesburg, is also of the opinion that the situation is critical and that load shedding will be unavoidable.
We hope the following information will be of interest as, if our information is correct, we will have to look to alternative sources of energy over the next few years.
GENERATORS / SOLAR
A local resident – Mr. Rudi Wellmann (an engineer)– has sent us the following information:
When you have equipment like PCs that HAVE to keep running during load shedding, a simple UPS is not enough since most of them will only give you around 15 minutes backup. They are ideal to provide bridging power while another power source (typically a generator) starts up, stabilizes, and then takes over.
The cheapest options (I can think of) for generating the backup power are
1. generator
2. a battery array + inverter (i.e. a very large UPS)
Here you have a choice of how to charge the battery bank…
a) with a charger powered from Eskom power
b) with a solar PV charger
In both cases you will typically have to install some dedicated plugs and wire in a few other connections in your house (e.g. a few critical lights, and perhaps your fridge/freezer, since usually the backup is not big enough to simply take over powering everything.)
Notes on Generators
Drawbacks:
1. You need to have a reasonable amount of fuel on site for the generator
(there are all sorts of rules and regulations on this)
2. Generators that are only used occasionally tend to require even more
maintenance than ones that are used frequently, but their running costs in
(c/kWh) is much higher than using Eskom power so you do not want to run it too
much either
3. They are quite noisy and make some exhaust fumes.
4. Auto start-up and auto stop is typically only supported in the bigger (more
expensive) models.
5. Some generators tend to produce dips/spikes when the load changes suddenly. Choose carefully what is connected. (e.g. laser printers are known to be troublesome).
Good aspects:
1. Simple enough to do yourself
Notes on the battery array + inverter.
Drawbacks:
1. Higher up-front cost compared to generator.
2. Higher running/operating costs compared to generator.
3. Batteries age quickly – especially if they are discharged deeply.
You will have to replace the battery bank every 3-6 years depending on use.
4. Depending on the type of battery you could have –
nasty fumes when they are charged
fire hazard
5. You need someone who knows what they are doing to set this up
(you can try Current Automation http//www.rectifier.co.za/)
Good aspects
1. No noise problem, no exhaust fumes
2. Can be set up to have glitchless switchover, so you do not need other UPS’s on
your PC’s etc.
3. To get a longer back-up time one can simply add more batteries in the battery
array
It is also easy to use solar PV panels to charge such a battery array but it would be a waste if you do not use the power every day since in pure backup situations that battery will be full most of the time, so the PV panels will not actually be doing much. However if you use the system every day the battery will age very quickly, resulting in higher operating cost.
The bad news is that any which way you do this you will end up with a system that has a higher running cost than what Eskom is charging so you end up paying a lot of money for something that is not used much (a bit like insurance).
Other notes:
Back-up systems like the above normally can NOT handle large loads like a stove/oven, kettle or geyser.
I have changed my stove to a gas unit last time we had lots of load shedding.
You should definitely consider changing your geyser to a solar type or (my preferred option) a heat pump system. Both options will save you enough power to reach a return-on-investment within a few years.
Another thing I have tried so far was to replace my swimming pool pump with one that can operate from solar PV panels. The pump starts when the sun comes up and stops at sundown. No timer to set, no batteries at all and no connection to Eskom. This system is simple and standalone, and I calculated that I will reach return-on-investment in about five years.
