Alternative power options for estates

Residential Security Handbook 2022: Smart Estate Living Editor's Choice, Perimeter Security, Alarms & Intruder Detection

Solar power gets its fair share of attention these days, especially in light of the abysmal performance of Eskom and horrendous service from municipal power suppliers we have to deal with. And while there are benefits to solar power, is it a good option for estates, especially the large ones with large tracts of open land?

Hi-Tech Security Solutions asked three people involved in the energy business about the pros and cons of solar power, what estates should pay attention to in order to ensure they purchase solar solutions that deliver the optimal efficiency, what should they look out for when choosing a supplier and/or installer and also about the other alternative power options available to estates. Answering our questions are:

• Marius Du Preez, sales manager, Energon SA.

• Hennie Heymans, founder and director, Henka Solar.

• Lance Dickerson, MD of REVOV.

Hi-Tech Security Solutions: Does it make sense to install solar panels as an alternative power source on estates? What would estates have to pay attention to in order to ensure they purchase solar panels that deliver the optimal efficiency? What should they look out for when choosing a supplier and/or installer?

Du Preez: More and more we see a trend of estates opting for solar power, either individual owners or the estate as a whole. The estate would have to ask for ‘A’ Grade panels to maximise the draw from the sun. Obtaining warranties on these units as well as your inverters and batteries is a must. A well trusted supplier will be able to recommend an approved installer.

Heymans: To answer the first question, yes, solar energy in South Africa makes a lot of sense in terms of:

1. Financial benefits

2. Security of supply with regards to electricity.

Although large estates do have plenty of space, the options one needs to consider is to erect a single solar farm which would be a central collection point for solar energy, versus mini solar farms scattered around the estate grounds. Both options come with their benefits and drawbacks, but from a security of supply and redundancy perspective, I am a strong advocate for mini solar farms and to be more specific, mini solar farms for each household for the following reasons:

1. The solar farm/system can be customised for the specific household and its energy needs.

2. If you do encounter any technical problems, it would only be that household or portions of the household that would be affected and not widespread.

3. Cost is a big factor in solar systems and each household would be able to determine its own budget.

Technology with regards to solar panels has come a long way since the first solar panels were introduced for the commercial and residential markets. The first solar panels were called polycrystalline solar panels, which means the panel is made up of solar cells which are blended from multiple silicon sources.

The panels more widely used today are monocrystalline solar panels that are cut from a single source of silicon. Monocrystalline solar panels are more efficient than polycrystalline and generally also do not require specific orientation with regards to the positioning of the sun.

Added technologies to monocrystalline solar panels e.g., PERC (Passivated Emitter and Rear Cell technology) further increases their efficiency. I would therefore recommend that monocrystalline solar panels be used for rooftop installations. Also note, these solar panels come in different sizes which are mostly determined by the wattage they can produce.

With the solar market in South Africa taking off and people recognising the short- and long-term benefits of solar energy, there has equally been an increase in solar installers. This makes it extremely important to ensure you use a reputable installer that uses quality products and provides optimal workmanship in the installation. The best advice is to ask for a portfolio of evidence of previous installations done, a good reference sample would be 20-30 previous installations to assess workmanship and quality.

Most important is to recognise a solar installation needs to conform to different pieces of legislation and standards. Ensure that your installer can provide you with the necessary documentation to ensure your solar installation conforms. One of the basic documents is an electrical CoC (Certificate of Compliance), which you would require for insurance purposes. It is also advisable to obtain a manufacturers’ warranty letter from your installer due to the warranty period of the solar components being five to 10 years for batteries and inverters. Also, ensure your product is locally repairable with the manufacturer to avoid lengthy waiting periods.

Dickerson: It would make sense to install solar panels as an alternative power source for estates, however, there are several considerations that need to be taken into account. For instance, do they want to be totally off-grid or just provide backup in times of failure, or do they want a hybrid system that reduces cost and improves reliability?

Totally off-grid means having a complete alternative, where solar generation is sufficient to run the estate during the day and charge up batteries for night-time use or periods of low solar intensity.

Providing for backup in times of failure needs a battery bank which is correctly sized to provide essential loads during grid downtime. These systems can sometimes include solar arrays to reduce the battery requirements during daytime outages, or simply have UPS-styled battery systems that wait for outages and then switch on. Recharging is via the grid and starts immediately when the grid becomes available again.

A hybrid system could be used to provide cheaper energy at times of higher tariffs, if such structured tariff schedules are in place, or they could be used to reduce costs by replacing some grid usage with solar and battery. They typically also provide added uptime as a benefit.

Estates need to be aware that PV can only power a house when there is sun available. When there is no sun, no electricity will be produced and batteries will need to be installed. (Poly and Mono PV Panels: Mono PV are the best as they can work better than Poly in cloudy weather. Solar panels can still work during rainy days; however, their production may be lower than usual. When there is no sun and the PV (photovoltaic) panels are not generating electricity, batteries are able to provide power.

When choosing a supplier/installer, estates should do their research on the supplier/installer’s product and previous installations, their choice of components and how their installations have been put together. REVOV has a list of recommended installers for anyone looking for reputable installers. Reputable installers will all have simple energy meters which they can install to confirm peak and normal usage. This, combined with the desired critical and non-critical loads, will determine the system size needed.

Panel array sizing is very important. The array must be able to provide the peak load for all the connected appliances and be able to charge the battery bank simultaneously. Given the actual sun availability in SA, it should be assumed that we get approximately six hours of sun per day on average, so the batteries have only six hours in which to be charged (if we assume an off-grid scenario).

A hybrid scenario would use grid power to top up the batteries if by a certain time of day the batteries are not above a certain level from a state-of-charge perspective. REVOV supplies energy storage and as such we do not purport to be solar panel experts, which is why we work closely with reputable experts in the industry.

Hi-Tech Security Solutions: What is important when selecting batteries? Users want a reliable power supply from them as well as a decent lifespan. What would be a reasonable, expectable lifespan for different types of batteries?

Du Preez: Batteries are essential to store power for use at night. If you only want to be covered in the day, you could leave out the battery component of the system, but will be at a loss on days that aren’t so sunny.

Depending on the user’s budget, AGM (Absorbent Glass Mat), gel or carbon batteries are good (recommended) for solar systems. Always make sure that the battery you are buying is intended for use in a solar set-up. Lithium, on the other hand, can give you a longer lifespan and more cycles, but they are very pricey. AGM, gel or carbon batteries are more cost-effective and very reliable, our carbon range can give up to 3900 cycles and it has a lifespan of 15 years.

Heymans: In this area there is much speculation and difference of opinion. There are basically three types of battery technologies:

1. Lead acetate.

2. Gel/AGM.

3. Lithium.

The battery technology you choose will mainly depend on the amount of space available. Lithium batteries are more compact thus more energy dense than lead acetate or gel/AGM batteries. For this reason, most residential and commercial installations are done with lithium batteries.

The bonus is that lithium batteries also use a technology called BMS (Battery Management System) which means a device manages the battery in such a manner that it is not damaged during usage by ensuring equal cell operation in discharging and charging. It will also shut down the battery in case of any problems, thus protecting it. Most quality lithium batteries BMSs can communicate directly with the inverter installed, thus providing a direct link between the inverter and the batteries for optimal battery maintenance and usage without the need for parameters being defined.

Lithium batteries are not all created equal as with all consumer products. Lithium batteries have a life span of between 5000 and 7000 cycles. A cycle is defined by a discharge and charge to optimum level. In most instances it can be translated to 10 to 15 years dependant on usage and maintenance. The gel or AGM batteries have a normal lifespan of four to seven years with lead acetate at about three to five years. The lifespan of the non-lithium batteries all depends on the usage of the battery and by this I mainly refer to the level of discharging and charging cycles.

Dickerson: When selecting batteries, it is important to look at the price, convenience, impact on the environment and the load size needed to power a home. Batteries need to be sized to accommodate the peak and average loads during and after sun outages. Sun outages cause the primary load to not be serviced, but they also cause the battery storage to not be fully topped up.

The worst thing that can happen is for the batteries to either be undercharged once the sun stops charging or to be undersized. This would then cause an outage during the night and limited power up until the time that the sun starts to provide full energy again. Of course, the grid can be used to top up the batteries in these extreme times, however, this is not ideal and in an off-grid scenario it’s not possible.

The most common batteries used for backup power solutions are lead acid and lithium iron phosphate (LiFe). Lithium iron batteries have a life that is three times as long as lead acid batteries, have fewer safety risks and require negligible maintenance. Although lead acid batteries are cheaper from an initial cost point of view, the total cost of ownership throughout a system lifespan is significantly higher due to the requirement to replace them more often.

LiFe batteries tolerate considerable abuse and big variations in temperature and are significantly cheaper to keep charged up. Lead acid batteries also require a more knowledgeable design and maintenance to keep systems working well and they don’t last as long as an equivalent LiFe battery pack. The recharging of lead acid batteries will be two or three times slower, drag over hours rather than the quick one-to-two-hour process with lithium iron. Lithium iron is a more convenient and safer alternative to lead acid. It’s much more of an ‘install-and-forget’ solution as you move off-grid.

Hi-Tech Security Solutions: Which batteries deliver the best performance (gel, lead acid etc.), and what tips can you give to ensure the best performance and lifespan?

Du Preez: As mentioned, AGM, gel or carbon have proven to be very reliable and cost-effective. Our gel range has a lifespan of 10 to 12 years with 2500 cycles. The carbon range has a life expectancy of 15 years and will give you 3900 cycles. When you use the correct battery meant for the specific vertical, it will live longer and perform optimally.

Heymans: I personally prefer the lithium batteries for solar installations for the previously mentioned facts that they are:

• More compact, thus more energy dense and save space.

• Use BMS technology that manages and protects the battery and extends its lifespan.

Whatever battery you choose to have installed, make sure that you use a good quality battery from a reputable company that has been in the market for a good number of years and can provide you with a warranty certificate. They should also have a local repair agent.

Secondly, the way you use the battery is critical in extending its lifespan. Do not over discharge your battery to lower than the subscribed voltage as it will reduce your battery’s lifespan. The depth of discard for most gel/AGM and lead acetate batteries is not lower than 12 V or 60% to 55%. Lithium batteries can be discarded much lower than that to between 85% and 99%.

Dickerson: The most common batteries used for backup power solutions are lead acid and LiFe. Although lead acid batteries are cheaper, LiFe batteries tolerate considerable abuse and big variations in temperature and are significantly cheaper to keep charged up.

Most of REVOV’s ‘second life’ batteries ( were originally designed with a life expectancy of 6000 to 7000 cycles. Once they have endured 1500 to 2000 cycles in a vehicle, the cells still have a life expectancy of another 4000 to 5000 cycles under the same conditions as in the vehicle. However, stationary storage reduces the stresses on the battery cells enormously compared to their design capability and hence the life span of the 5000 to 6000 additional cycles is easily met.

Tips to ensure the batteries’ best performance and lifespan is to ensure that the installation is designed correctly for the power needed. When using backup systems, it is always important to run only high priority loads. Ensure the correct charge profile has been set up and the correct amount of PV is installed in the system.

Hi-Tech Security Solutions: While solar power is popular, would it not make more sense to install a generator(s) for alternative and reliable power – or are generators intended more for when Eskom blackouts occur rather than continual power supply?

Du Preez: This is all dependant on the user’s budget. Generators are very noisy and need constant maintenance and fuel, which is not environmentally-friendly. Solar power is sustainable and does not use fossil fuels to create power. This is the environmentally-sensible solution and could be cost-effective even though the initial outlay is quite substantial.

Heymans: Generators have a place as an alternative power source, but one needs to assess your power needs and design accordingly. What one needs to consider is the fact that although a generator costs much less initially (for the generation per kilowatt) than a solar system, that cost will over a period of time ‘swing’ the other way due to the fact that generators have much higher running costs:

1. Generators need fuel, either diesel or gasoline to run.

2. Generators need to be serviced every year or after a certain amount of running hours.

3. Worn parts need to be replaced and repaired.

One also needs to recognise the fact that generators cannot run for extended periods of time, thus if you have a power outage of more than eight hours you will have to give your generator a rest as most generators can normally run for four to five hours at 50% load and for eight to nine hours on full load. Additionally, if you have sensitive electronic equipment in your house or business, an inverter solar system would be much better in keeping the power to these units stable, not only in terms of the power voltage (over and under), but also the power frequency.

Most generators fluctuate greatly when it comes to power voltage and frequency, especially with variable load conditions. Thus, if you have electrical equipment that is sensitive to power fluctuations, you are much better off utilising an inverter linked to solar as a power source. Generators can always be used in conjunction with solar as a last resort, but this means your inverter remains your gatekeeper to protect against power fluctuations.

Dickerson: In the long term, it’s better to invest in battery back-up or solar and battery back-up, than a generator. Although a generator may cost less initially, it requires diesel to operate, creates air and noise pollution and the cost of diesel is also likely to increase.

If we believe that diesel and grid power is going to reduce in cost over time, then perhaps batteries are not the ideal solution economically, however, this is unlikely. Generators will possibly provide a lower cost of entry but will certainly have higher running and maintenance costs over the 10- to 15-year periods we are talking about.

Current talk is of diesel prices possibly reaching R40 a litre in SA during 2023. If this does indeed happen, power from generators will not be economical. It should also be noted that given the current state of Eskom’s network and infrastructure, a larger and larger portion of our power is coming from diesel-fired generators, meaning that the cost of Eskom’s generated power will also increase.

There are several reasons why generators aren’t ideal for home users, namely, noise from the generators, dangers of portable generator fumes, dependence on fuel, environmental pollution and prices of generators in South Africa.

When investing in a battery-based backup for your home to alleviate the impact of load-shedding, there are several advantages:

1. No noise – operates silently and seamlessly.

2. Clean – doesn’t burn fuel.

3. Safe – no fumes or polluting.

4. No ongoing maintenance.

5. Long-term value – no running costs.

Hi-Tech Security Solutions: What solutions and services does your company supply in the power market?

Du Preez: Energon South Africa is a well-trusted brand in the energy market, our products range from backup power solutions to megawatt storage units. All our batteries are AGM and we also supply solar products that include panels and inverters.

We will soon also have power walls that are completely stand-alone and easy on the eye. Within months we will assemble our own lithium units in SA that will be very cost-effective and readily available. Using the right product in the right vertical will prolong the life of your system. There are more applications for solar power in estates than just household use. We also have batteries to support these various ancillary applications.

Heymans: The company specialises in residential and commercial solar solutions and designing the complete system such that it can maximise your energy usage for your specific needs. What we do as a company before we issue a quotation:

1. We do average power consumption together with instantaneous maximum demand, which is measured over a period of time, normally 10 days.

2. Thereafter we analyse the data and the ‘big’ power usage items are looked at in terms of modernisation to reduce energy consumption e.g., normal air conditioner technology vs inverter technology.

3. All our systems are designed in a modular fashion, which means if you, as the client, want to upgrade for whatever reason, you can do so to increase your power generation or storage, or start small and add onto your system as your demand grows.

4. We also have a professional tactical and surveying division that surveys the premises via powerful software and aerial photography to give our clients the optimal design and layout on solar panel designs.

5. We have close collaborations with all major solar technology companies, thus ensuring that we say up-to-date with all new technology developments and can influence repairs in a quick and effective manner.

6. We have a portfolio of more than 400 installations in the past two years, not counting returning clients.

Dickerson: REVOV does not install solar, instead it provides LiFe batteries which are the perfect fit for stationary storage solutions.

REVOV is an energy storage solutions company that sells carry-case sized LiFe batteries either as single units or in powerful systems of up to 200 batteries. Known for its second life LiFe products, REVOV services wholesalers, installers and end users, providing energy backup for SA’s unstable grid, renewable energy sources and the growing demand throughout sub-Saharan Africa. Carbon-conscious, agile and responsive, REVOV is run by a team that lives and breathes energy storage and superior lithium iron power.

Lead acid is not dead

While there are a number of options available when choosing battery technology to support your solar or any other alternative energy solutions, most people seem to think lead acid batteries are a poor choice for a number of reasons, from their age, to discharge limitations and more. In fact, lead acid batteries (LA) are still selling well and many people and companies rely on them.

Forbatt SA sells LA and gel batteries (along with a number of security solutions). Forbatt’s Mark Dove says LA batteries are still a good choice for almost any users due to the safety factor. These batteries have had decades of development and provide a stable and safe solution to customers.

Dove admits that lithium-ion batteries (LI) are more modern and have faster recharge times, but the technology is still relatively new and needs more development. As an example, thermal runaway is an issue in LI. This happens when heat generated by the battery is not released and builds up in the battery. This can lead to swelling and even explosions. Dove says Forbatt LA batteries are designed for safety and will expel heat and gas before any problems occur.

There is also the question of costs. LI is much more expensive than LA. And although it sounds counterintuitive, because LI are smaller and lighter than LA batteries, they are easier to steal. Considering a 200 A battery, the LA version will weigh around 60 kg, while a LI one comes in at around 8 kg. Running away with a stolen 60 kg battery is not going to be easy.

Despite this, Dove notes that LI batteries are the future and after some further development they will be a hard battery technology to beat. Forbatt will also manufacture LI batteries in future. For now, LA is still the technology to beat and Forbatt has ensured it still has stock despite the global supply chain problems; being a manufacturer allowed the company to ensure it had supplies in stock to build batteries. So, while we will see dramatic development in batteries in the next few years, the market for LA batteries is not going anywhere for now and the number of people relying on this technology will continue to increase.

For more information contact:

• Energon SA, Marius Du Preez, +27 10 300 6050, [email protected],

• Henka Solar, Hennie Heymans, +27 78 882 3100, [email protected]

• REVOV, +27 10 035 6061,


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