With the rapid increases in the price of electricity and water over the past decade, the question is:Â what does a shower or bath cost in South Africa in 2024?
Most South Africans are aware of the rapidly rising price of electricity (a 937% increase over the period 2007-2024), but the price of water has also been increasing rapidly over the same period.
South Africans tend not to think twice about the cost of a shower or bath, since both electricity and water used to be very inexpensive.
Is this still true in 2024? Our previous studies in 2022 and earlier were real eye-openers, with the cost of a 10-minute shower using a 15 litre/min showerhead coming to just over R21/shower!
We have now updated the study using the latest approved municipal tariffs for the tariff year July 2024 to June 2025. As you might guess, things look worse than they did last year.
Here is the summary data for 2024 to 2025.
For an average middle-class household in South Africa (LSM7-10), a 10-min shower costs over R24 if you have a ‘standard’ 15 litre/min showerhead! This is about R2.43/min. By changing to a low-flow showerhead and reducing shower time to 6 minutes, you can dramatically reduce this to about R7.78 per shower (or R1.30/min).
In either case, it appears that the days of ‘cheap’ showers are numbered, and we can all do with being more aware of just how much water & electricity we use in the shower or bath.
Conventional wisdom has it that showering uses less water than running a bath. However, a typical bath uses 90 litres of water, so if you shower for longer than 6 minutes with a ‘standard’ showerhead, you will actually use more water than if you had a bath… With an average shower time internationally of 8 minutes, a shallow bath might actually be better for your pocket and the environment!
Of course, even better than a shallow bath is to switch to a low flow showerhead and have shorter showers… During the ‘Day Zero’ water crisis, City of Cape Town recommended showering for less than 2 minutes, and switching to low-flow showerheads (less than 10 litres/min) is compulsory according to City of Cape Town bylaws.
The graphs below show more detailed information on water & energy use and cost per shower for normal & low-flow showerheads, and compared to a ‘standard’ 90 litre bath.
Average bath uses about 90 litres of water. Waterwise. Last accessed: 12/09/2017.
“Normal” or standard showerheads use 15 litres of water per minute or more, and low flow showerheads use about 8 litres water per minute. Eskom fact sheet on showerheads. Last accessed: 12/09/2017.
Average effective residential water & electricity tariffs were calculated from the published 2024/25 tariffs of the following four metropolitan municipalities: City of Johannesburg, City of Tshwane, City of Cape Town and Ethekwini, using the average residential water and electricity consumption values for LSM7-10 obtained from the above references.
For ‘low income’ households, the average marginal water tariff is somewhat lower across the four municipalities (due to lower average consumption), at R2.63/kWh for electricity and R47.24/kilolitre for water & sanitation. This yields a cost per bath of R11.11, a cost per 10-minute ‘normal showerhead’ shower of R18.52/shower, and a cost per 6-minute low-flow showerhead shower of R5.93/shower.
Energy cost of hot water based on heating water from 15 to 60°C, which requires approximately 5.22 kWh per 100 litre.
With the rapid increases in the price of electricity and water over the past decade, the question is:Â what does a shower or bath cost in South Africa in 2022?
Most South Africans are aware of the rapidly rising price of electricity (a 650% increase over the period 2007-2022), but the price of water has also been increasing rapidly over the same period.
South Africans tend not to think twice about the cost of a shower or bath, since both electricity and water used to be very inexpensive.
Is this still true in 2022? Our previous study in 2021 was a real eye-opener, with the cost of a 10-minute shower using a 15 litre/min showerhead coming to just under R20/shower!
We have now updated the study using the latest approved municipal tariffs for the tariff year July 2022 to June 2023. As you might guess, things look worse than they did last year.
Here is the summary data for 2022 to 2023.
For an average middle-class household in South Africa (LSM7-10), a 10-min shower costs over R21 if you have a ‘standard’ 15 litre/min showerhead! This is about R2.10/min. By changing to a low-flow showerhead and reducing shower time to 6 minutes, you can dramatically reduce this to about R6.70 per shower (or R1.12/min).
In either case, it appears that the days of ‘cheap’ showers are numbered, and we can all do with being more aware of just how much water & electricity we use in the shower or bath.
Conventional wisdom has it that showering uses less water than running a bath. However, a typical bath uses 90 litres of water, so if you shower for longer than 6 minutes with a ‘standard’ showerhead, you will actually use more water than if you had a bath… With an average shower time internationally of 8 minutes, a shallow bath might actually be better for your pocket and the environment!
Of course, even better than a shallow bath is to switch to a low flow showerhead and have shorter showers… City of Cape Town recommends showering for less than 2 minutes, and switching to low-flow showerheads (less than 10 litres/min) is compulsory according to City of Cape Town bylaws.
The graphs below show more detailed information on water & energy use and cost per shower for normal & low-flow showerheads, and compared to a ‘standard’ 90 litre bath.
Average bath uses about 90 litres of water. Waterwise. Last accessed: 12/09/2017.
“Normal” or standard showerheads use 15 litres of water per minute or more, and low flow showerheads use about 8 litres water per minute. Eskom fact sheet on showerheads. Last accessed: 12/09/2017.
Average effective residential water & electricity tariffs were calculated from the published 2022/23 tariffs of the following four metropolitan municipalities: City of Johannesburg, City of Tshwane, City of Cape Town and Ethekwini, using the average residential water and electricity consumption values for LSM7-10 obtained from the above references.
For ‘lower income’ households, the average water & electricity tariffs are somewhat lower across the four municipalities (due to lower average consumption), at R2.57/kWh for electricity and R45.30/kilolitre for water & sanitation. This yields a cost per bath of R10.78, a cost per 10-minute ‘normal showerhead’ shower of R17.97/shower, and a cost per 6-minute low-flow showerhead shower of R5.75/shower.
Energy cost of hot water based on heating water from 15 to 60°C, which requires approximately 5.22 kWh per 100 litre.
With the rapid increases in the price of electricity and water over the past decade, the question is:Â what does a shower or bath cost in South Africa in 2021?
Most South Africans are aware of the rapidly rising price of electricity (a 650% increase over the period 2007-2022), but the price of water has also been increasing rapidly over the same period.
South Africans tend not to think twice about the cost of a shower or bath, since both electricity and water used to be very inexpensive.
Is this still true in 2021? Our previous study in 2017 was a real eye-opener, with the cost of a 10-minute shower using a 15 litre/min showerhead coming to just under R13/shower.
We have now updated the study using the latest approved municipal tariffs for the tariff year July 2021 to June 2022. Unfortunately things have only gotten worse…
Here is the summary data for 2021.
For an average middle-class household in South Africa (LSM7-10), a 10-min shower costs almost R20 if you have a ‘standard’ 15 litre/min showerhead! This is about R1.95/min. By changing to a low-flow showerhead and reducing shower time to 6 minutes, you can dramatically reduce this to just over R6 per shower (or R1.04/min).
In either case, it appears that the days of ‘cheap’ showers are numbered, and we can all do with being more aware of just how much water & electricity we use in the shower or bath.
Conventional wisdom has it that showering uses less water than running a bath. However, a typical bath uses 90 litres of water, so if you shower for longer than 6 minutes with a ‘standard’ showerhead, you will actually use more water than if you had a bath… With an average shower time internationally of 8 minutes, a shallow bath might actually be better for your pocket and the environment!
Of course, even better than a shallow bath is to switch to a low flow showerhead and have shorter showers… City of Cape Town recommends showering for less than 2 minutes, and switching to low-flow showerheads (less than 10 litres/min) is compulsory according to City of Cape Town bylaws.
The graphs below show more detailed information on water & energy use and cost per shower for normal & low-flow showerheads, and compared to a ‘standard’ 90 litre bath.
Average bath uses about 90 litres of water. Waterwise. Last accessed: 12/09/2017.
“Normal” or standard showerheads use 15 litres of water per minute or more, and low flow showerheads use about 8 litres water per minute. Eskom fact sheet on showerheads. Last accessed: 12/09/2017.
Average effective residential water & electricity tariffs were calculated from the published 2021/22 tariffs of the following four metropolitan municipalities: City of Johannesburg, City of Tshwane, City of Cape Town and Ethekwini, using the average residential water and electricity consumption values for LSM7-10 obtained from the above references.
For ‘lower income’ households, the average water & electricity tariffs are somewhat lower across the four municipalities (due to lower average consumption), at R2.37/kWh for electricity and R37.88/kilolitre for water & sanitation. This yields a cost per bath of R9.59, a cost per 10-minute ‘normal showerhead’ shower of R15.98/shower, and a cost per 6-minute low-flow showerhead shower of R5.11/shower.
Energy cost of hot water based on heating water from 15 to 60°C, which requires approximately 5.22 kWh per 100 litre.
Please note: this article has been updated – click here for the 2021 version.
With the rapid increase in the price of electricity and water over the past few years, the question is: what does a shower or bath cost in South Africa in 2017?
Most South Africans are aware of the rapidly rising price of electricity (a 300% increase in the period 2007-2015 alone), but the price of water has also been increasing rapidly over the past few years.
For example, here are the water & sanitation tariff increases effective July 2017 for the four major metropolitan areas:
Ethekwini 17%
City of Johannesburg 12.2%
City of Tshwane 10.2%
City of Cape Town:
13.2%Â for 6 – 10.5 kl (kilolitres)
29.7%Â for 10.5 – 20 kl
27.2%Â for 20 – 35 kl
128.8%Â for 35 – 50 kl
These increases are all much higher than inflation. All these municipalities have also done away with the free water allocation of 6 000 litres (6 kilolitres), except for people registered as indigent.
Of course, there is a serious drought in Cape Town, and so the increases seen there might be more justifiable.
South Africans tend not to think twice about the cost of a shower or bath, since both electricity and water used to be very inexpensive.
Is this still true in 2017? We did some calculations and the result is an eye-opener.
For an average middle-class household in South Africa (LSM7-10), a 10-min shower costs almost R13 if you have a ‘standard’ 15 litre/min showerhead! This is about R1.30/min. By changing to a low-flow showerhead and reducing shower time to 6 minutes, you can dramatically reduce this to just over R4 per shower (or 70c/min).
In either case, it appears that the days of ‘cheap’ showers are numbered, and we can all do with being more aware of just how much water & electricity we use in the shower or bath.
Conventional wisdom has it that showering uses less water than running a bath. However, a typical bath uses 90 litres of water, so if you shower for longer than 6 minutes with a ‘standard’ showerhead, you will actually use more water than if you had a bath… With an average shower time internationally of 8 minutes, a shallow bath might actually be better for your pocket and the environment!
Of course, even better than a shallow bath is to switch to a low flow showerhead and have shorter showers… City of Cape Town recommends showering for less than 2 minutes, and switching to low-flow showerheads (less than 10 litres/min) is compulsory according to City of Cape Town bylaws.
The graphs below show more detailed information on water & energy use and cost per shower for normal & low-flow showerheads, and compared to a ‘standard’ 90 litre bath.
References, methodology & assumptions for calculations
Average bath uses about 90 litres of water. Waterwise. Last accessed: 12/09/2017.
“Normal” or standard showerheads use 15 litres of water per minute or more, and low flow showerheads use about 8 litres water per minute. Eskom fact sheet on showerheads. Last accessed: 12/09/2017.
Average effective residential water & electricity tariffs were calculated from the published 2017/18 tariffs of the following four metropolitan municipalities: City of Johannesburg, City of Tshwane, City of Cape Town and Ethekwini, using the average residential water and electricity consumption values for LSM7-10 obtained from the above references.
For ‘lower income’ households, the average water & electricity tariffs are somewhat lower across the four municipalities (due to lower average consumption), at R1.65/kWh for electricity and R23.47/kilolitre for water & sanitation. This yields a cost per bath of R6.42, a cost per 10-minute ‘normal showerhead’ shower of R10.70/shower, and a cost per 6-minute low-flow showerhead shower of R3.40/shower.
Energy cost of hot water based on heating water from 15 to 60°C, which requires approximately 5.22 kWh per 100 litre.
Energy storage is projected to grow rapidly in the USA over the next few years, according to an interesting Utility Dive article. Growth in the past year was over 40%, and they are projecting similar growth rates over the next few years.
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In the article they state that “Cost-effective energy storage is widely seen as the “holy grail” for reaching higher penetrations of renewables and distributed energy resources — it’s the one emerging technology that enables the rest.” (bold added)
Some utilities in the US are also looking to energy storage to defer further capital investment in new generation capacity and infrastructure upgrades: “ConEd’s plan to use storage and other demand side management strategies to defer billion dollar investments in substations and other grid upgrades shows energy storage’s potential for capacity deployments.” (bold added)
As the cost of batteries comes down even faster than forecasts predicted (see how Tesla and Nissan are leading the ‘pack’), and the reductions in solar panel costs continue, it seems that a transition is in sight where solar plus storage will become viable economically, and not just in the USA. With the rapidly rising cost of electricity in South Africa, combined with the impetus given by load-shedding, we could also see faster adoption of these solutions locally. This might happen even without regulatory or tariff incentives.
Already there is a plethora of businesses that have sprung up to service this new market in South Africa, although many of these operators might not be around for long, and quality of service and technology is a concern. (See this article for some tips around selecting a battery storage system.)
As residential and commercial electricity customers start turning to solar for reducing dependence on the grid and reducing the inconvenience and cost of load-shedding, issues like grid stability, feed-in tariffs and the cost of maintaining the infrastructure will become a concern for Eskom and municipalities.
This is because solar without storage will reduce their electricity sales but not the morning and evening peak demand, and will not reduce their infrastructure and maintenance costs. When feed-in tariffs are added to the mix, they become even less profitable.
This is not a new issue, and has been resolved internationally through adding fixed charges to the electricity bill, or increasing peak charges to incentivise customers to add their own storage capacity. For example, the same Utility Dive article states that:
“… utilities are attempting to reduce the rates at which they compensate rooftop solar owners for the electricity they put back onto the grid… More recently, Arizona municipal utility Salt River Project instituted a higher demand charge for solar customers based on their peak energy usage each month.”
Whatever happens, it will certainly be interesting to watch things unfold in SA. Perhaps we will look back in 20 years and decide that the current electricity crisis was a good thing, in that it spurred the transition from a fossil fuel-dependent electricity supply to more renewable and distributed generation.
Indeed! This brings us to the issue of load shedding.
Load shedding is when electricity supply is intentionally interrupted or reduced to avoid excessive load on the generating plants. Whilst it is very disruptive (as we all know!), it is preferable to a total collapse of the electricity supply grid, which will have disastrous consequences for the country. Should the demand be allowed to exceed the supply, it could very well happen and it would take a week or longer to get the grid online again.
2020 Update notes:
1. Please note that this article was written in 2015. Some of the recommendations might be outdated. For example, the price of lithium ion batteries have dropped dramatically since 2015 and have now become a viable alternative to lead acid batteries, with superior life, efficiency and general performance.
2. Please note that PowerOptimal does not sell or install inverter-based solar photovoltaic systems or battery backup systems. This article is provided for general information as a service to the public and not as marketing for our products. (We do manufacture and sell the Elon solar PV water heating system – this is a unit that allows direct connection of solar photovoltaic modules to a standard electric geyser, without an inverter.)
“If it weren’t for electricity we’d all be watching television by candlelight”
When a software glitch allowed such an imbalance to develop in 2003, the entire North-eastern and Midwestern United States and the Canadian Province of Ontario were blacked out, which left 55 million people without power for more than a week. A lack of alarms left operators unaware of the need to redistribute power after overloaded transmission lines hit unpruned foliage. Even in a technologically advanced country like the United States it can happen.
The first thing we need to realise is that load shedding will be part of our lives for several years to come. The second thing to realise is that it will get worse before it gets better. The next thing to realise is that we have no choice but to manage the situation according to our own specific needs.
Some of us could quite happily go without Sewende Laan, the Premier Soccer League and the Internet for several hours per week. For most of us though, a power failure not only spells inconvenience but a serious financial impact. Many small businesses face financial ruin. Business continuity is critical.
Backup power options for load shedding
If you cannot live with load shedding, your only alternative is to use stored energy when the lights go out and you really only have two choices, namely a generator or an inverter/ battery system.
What is an inverter? Basically it is an electronic or electrical device that changes DC (direct current) into AC (alternating current). It is required for when you want to use a battery storage system for backup power to your home or business, since the batteries deliver direct current and your devices / appliances run on alternating current.
In most cases, inverter/ battery systems offer superior performance and significant cost savings when compared to generators. Considering the efficiency of modern, solid state inverters, generators have definite drawbacks in several areas.
Most importantly, many body corporates, home owners associations, business parks and other landlords will not allow generators to be used. You can imagine the noise and smell when 200 generators start up in a complex.
The initial cost of a generator might be less expensive than an inverter system, but in the long run they are far more costly when you consider running costs and maintenance. Generators require constant attention to assure proper operation. The oil needs to be changed regularly and other maintenance performed. It is also highly recommended that if a petrol generator does not run for more than 30 days, that the fuel is drained and the carburetor run dry. Nobody wants to go outside at night and perform a fault finding ritual when the generator fails to start.
Buying a cheap unknown brand of generator is penny wise and pound foolish. Very few are supported and even a minor unobtainable spare part could leave you in the dark once again. Connecting your expensive equipment to a unit with dubious or compromised circuitry may very well be a perilous exercise. Also, if you believe everything you read, better not read the spec sheets of some of the cheap imports.
With the ever increasing price of fuel, running a generator could become prohibitively expensive. And nobody likes the noise and fumes.
Fuel storage can be a nuisance as well. Apart from the fire hazard and regulatory problems, petrol cannot be stored for more than a month or so. You need to rotate your inventory on a regular basis to avoid problems.
An important consideration is the seamless transfer of power of the inverter system, which is impossible to achieve with a generator. Even with the fastest automatic and remote start facility, there will always be a delay of several seconds before the power comes on. By that time you might have lost important data on your computer or, even worse, you might have lost the plot of the soapie you were watching!
Having said all that about generators, an inverter/battery system is not the be all and end all of standby power. There are several disadvantages, like the energy storage limitations of the batteries as well as their expected life, which is generally between 5 and 7 years. Initial cost is an important consideration but it is for the most part justified by the preceding reasons.
Even more so than with generators, the bandwagon is overcrowded with opportunists looking to make a quick buck. If you are on a limited budget, rather buy a quality inverter of the size you prefer with fewer batteries initially. You can always add batteries later on but if you buy a 1 kW inverter with 3kW written on the package, you might as well go and play the lotto. At least you will have a chance of getting value for your money.
What about Solar, you may well ask. Well, the truth is that if all you are trying to do is bridge the gap between power outages, Solar is not the answer. The inverter/battery system does not generate anything. It simply stores and provides energy when needed. Significantly, mains power is still by far the cheapest energy you can buy today, in spite of the drastic Eskom price increases. If, however, you want to become less dependent on Eskom power, Solar might be an option but it is still very expensive. All the same, that is a discussion for another day.
What size inverter/battery system is appropriate for my household or small business?
1 to 3 kilowatt inverter/battery systems are the most popular for households and small businesses. Bigger systems generally require dedicated designs by competent engineers, so we will focus on the smaller systems.
Although it is technically possible to design a system that can pick up the entire electrical load of a household or business, it is totally impractical because of cost. Therefore high consumption items like geysers, washing machines, heaters and even kettles should be avoided to keep the size of the inverter down and limit the number of batteries. Since our aim is simply to survive load shedding, it is not too difficult to find alternatives for these energy guzzlers. Computers and TV sets do not do too well on candle power however!
To illustrate what is achievable, typical examples of the three most popular systems give a good idea of what is realistic. The figures in the tables below are approximate. The actual power consumption of your household appliances or office equipment may vary considerably from the figures in this table. Before you do a final load calculation, we strongly recommend using an electricity usage monitor to establish how much electricity an appliance is using. They are simple to use and cost around R750.
1 Kilowatt System
Rated at 1000 Watts, the system can typically back up the systems below. However, it does not mean that it can sustain the full load all the time. That will be like driving your car flat out all day long. A constant load of about 80% as depicted in the example is sensible.
The system now runs at 80% but a photo copier or fax machine, which operates for a limited time could be used in addition. Should you want to operate your garage door (750 Watts), some of the other loads will have to be turned off for a short time while the door operates. It will however, not accommodate boiling water in a kettle (±2000 Watts) because it is way above the system’s 1000 Watt rating.
Flat Screen TV DStv Decoder or PVR Stereo System Desktop Computer LCD Computer Monitor Modem Alarm System 5 Lights Total
250 Watts 50 Watts 100 Watts 250 Watts 50 Watts 10 Watts 15 Watts 75 Watts       800 Watts
2 Kilowatt System
Rated at 2000 Watts, the system can typically back up the systems below. Even though the total Wattage exceeds the 2000 Watt rating a maximum constant load of about 80% (i.e. 1.6 kW) is recommended. Some loads such as a microwave or printer are used for a short period only and will not put an excessive burden on the system.
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You will obviously not use the microwave while something is being printed and it is a good idea to turn off the computer or the TV before using the microwave.
Flat Screen TV DStv Decoder or PVR Stereo System Desktop Computer LCD Computer Monitor Modem Alarm System 10 Energy Saver Lights Fridge Microwave Inkjet Printer Total
250 Watts 50 Watts 100 Watts 250 Watts 50 Watts 10 Watts 15 Watts 150 Watts 600 Watts 800 Watts 120 Watts    2395 Watts
3 Kilowatt System
Rated at 3000 Watts, the system can sustain most household appliances with the exception of high power consumption items like the geyser, stove, washing machine, dryer, air conditioner etc. It will also keep a small office with several computers, printers, copiers etc. going. Typical use is depicted below.
Flat Screen TV DStv Decoder or PVR Stereo System Desktop Computer LCD Computer Monitor Modem Alarm System Surveillance Camera Electric Fence 4 Security Lights 10 Energy Saver Lights 15 LED Downlights 2 Bedside Lamps Alarm Clock Cell Phone / iPad / Laptop Charger Fridge Freezer Total
A number of the following appliances may be used, provided some of the loads are turned off to make provision for the higher consumption. The total consumption of 3000 Watts may be exceeded within limits for a short period because the inverter system has built in safety margins and will not be damaged. However, if the safety margins are exceeded the system will automatically turn off to protect itself. PowerOptimal’s Powerguard® Peak Demand Management system could be employed to manage these tasks automatically and will ensure that limits are never exceeded.
Microwave Toaster Vacuum Cleaner Electric Iron Inkjet Printer
What type of installation is appropriate for my inverter/battery system?
There are essentially three different ways of employing standby power systems. For 1 – 2 kW systems, it makes sense to use Version 1 or 2. From 3 kW and above, Version 3 with automatic switching could be a serious consideration. Systems larger than 5 kW require a site inspection and a dedicated design.
Version 1
The inverter and batteries are contained in a steel cabinet, which is fitted with a standard 15Amp plug outlet. Castors make the unit easily movable, but it is not designed as truly portable because the batteries are heavy and the weight could be considerable. It is typically used in the vicinity where it is required or with an
 extension lead.
Version 2
The inverter unit is stored remotely and its output extended with its own cable via existing electrical conduit or surface mount to dedicated plug outlets that are completely isolated from the standard wiring. Potential problems with this solution are lack of space in the existing conduit or unsightly surface mounted cables.
Version 3
By employing the PowerGuard® DPM 30 – 8 Switcher, the inverter is permanently wired to the distribution board with minimal disruption during installation and present wiring remains untouched.
Unlike far too many risky installations, this perfectly legal connection complies with all regulations. Since it is impractical to use an inverter that is capable of picking up the full load, the PowerGuard® switcher ensures that high power consumption loads like the geyser and stove are turned off instantly during a power failure. With bigger units of 3kW and above, most other circuits like lights and plugs remain powered. Before installation, the client decides what should continue working during a power failure.
While we are on the topic of using existing wiring, a note of caution. Be very aware of wiring directly to your DB without a change over system that automatically and completely isolates the mains while running on the inverter. This is a serious fire hazard and while the electricity police will not come around and fine you, the insurance assessor will certainly take a keen interest in the wiring in the case of a fire damage claim.
What about battery types and sizes?
Although it is critical to use a high quality inverter capable of sustaining the design load, the batteries should also be of similar quality and of sufficient quantity. A bank of batteries with a combination of parallel and series connections provides the reservoir for the energy that has to be stored and later released when needed.
High performance lead acid batteries are usually used but they are not of the automotive type. While they are of similar construction, they are designed to withstand many more charge and discharge cycles and can also be deeply discharged. Known as a deep cycle battery, they can be cycled down to about 50% charge without incurring any damage. At that depth of discharge most of the potential energy had been extracted from the battery making them very useful for this application.
There are many varieties on the same theme ranging from the well known wet cell that requires regular maintenance to the more recently developed lead crystal with far superior performance and no maintenance whatsoever. As with all good things the superior performance naturally comes with a superior price.
The Sealed Maintenance Free Battery is reasonably priced and for that reason one of the more popular types. As the name suggests, it is to a large extent maintenance free, but the chemical reaction produces Hydrogen and Oxygen, which could form an explosive mixture. For that reason, these batteries cannot be used in a confined space and must be installed outside where it is well ventilated. They are generally about 35% cheaper than AGM batteries, which is the next step up.
In AGM (Absorbent Glass Mat) batteries, the electrolyte is mostly absorbed in glass fibre. This type of battery is entirely maintenance-free and there is no gas formation with normal use. Not requiring any ventilation, these batteries can be installed anywhere.
Batteries are rated in Amp Hour (Ah), which is a measurement of the amount of current it can supply over a certain period. They are rated over a period of 20 hours, which means a 100 Ah battery will supply 5 Amps over that period.
Simply put, the more Ah you have, the more capacity you have and the longer your system will produce power before the batteries run flat. To calculate the number of batteries required you may use the following rule of thumb. You need about one 100Ah battery per 1kW per hour. In other words if you have a 3kW system that should last for 4 hours you need 12 X 100 Ah batteries. 3 (3kW) X 4 (4 hours) = 12.
How can I contribute to reducing load shedding?
In spite of having alternatives for the times when the lights go out, all of us can contribute to limit load shedding to a minimum. We are in the middle of an energy crisis and each and every one of us needs to modify our lifestyles to accommodate this harsh reality. Here is what to do:
Switch off your geysers, electric heaters and pool pumps from 17h00 to 21h00 every day.
Switch off unnecessary appliances and lighting.
Consider alternative heating solutions (gas stoves, gas heaters, solar geysers, etc.).
Switch to CFL and LED lights.
Turn off anything that consumes standby energy (TVs, DVD players, computers, cell phone chargers).
Respond to the Power Alerts and Power Bulletin.
After all, saving electricity is a BRIGHT idea!
2020 Update notes:
1. Please note that this article was written in 2015. Some of the recommendations might be outdated. For example, the price of lithium ion batteries have dropped dramatically since 2015 and have now become a viable alternative to lead acid batteries, with superior life, efficiency and general performance.
2. Please note that PowerOptimal does not sell or install inverter-based solar photovoltaic systems or battery backup systems. This article is provided for general information as a service to the public and not as marketing for our products. (We do manufacture and sell the Elon solar PV water heating system – this is a unit that allows direct connection of solar photovoltaic modules to a standard electric geyser, without an inverter.)
On 12 March, the City of Johannesburg announced that PowerOptimal was selected as one of eight finalists in The Green City Startup competition hosted by the City of Johannesburg in partnership with Resolution Circle (see their website and Facebook page). The eight finalists will each receive R250 000 for their businesses, and will also receive support from Resolution Circle over a six month period. At the end of this period, two winners will be selected who will each receive R1m for their business.
The competition seeks to support “Revolutionary” and “Immediately Scalable” ideas Energy, Waste, Water, Transport or Building to help make Johannesburg a greener city. The competition is presented by the City of Johannesburg, in partnership with the University of Johannesburg and Resolution Circle.
The objective of the competition is to “accelerate visionary entrepreneurs in the green economy”.
On 4 and 5 March 2015, the top 20 companies pitched their businesses to a panel of judges. 8 companies will be selected as finalists for the next phase of the competition, and will receive R250Â 000 each to demonstrate the viability of their ideas. Six months later, two winners will be selected and will receive up to R1 million each.
You can follow The Green City Startup Competition on Facebook and Twitter (@thegcstartup). See also recent news coverage about the competition.
Ravi Naidoo, Executive Director: Economic Development & Tourism, launches the exciting competition:
We are very excited to announce the launch of PowerOptimal’s energy demand management and billing services!
Our energy demand management technology can cut your peak power demand by up to 50%, which can translate into substantial savings for commercial customers. Our innovative performance guarantee business model means that you don’t have to spend any money upfront to start saving.
Our billing management service for commercial City of Johannesburg electricity customers takes away the admin burden whilst helping you save. We can also help you correct billing errors and recover overpayments.
You can find a lot more information on our website – please contact us should you want to find out more!
By employing the PowerGuard® DPM 30 – 8 Switcher, the inverter is permanently wired to the distribution board with minimal disruption during installation and present wiring remains untouched.
