Many of us are working online from home due to the pandemic and a four-hour power outage can impact your productivity substantially but how do you mitigate this without breaking the bank? Solutions designed to keep wi-fi or ADSL routers powered are available below R1 000 and are simply a plug-and-play 12VDC to DC UPS. These units are roughly the same size as the router and employ Lithium-Ion batteries to store energy from the grid (or solar optional) and automatically switch over to battery back-up when the grid fails. A marginally more expensive version, less than R1 500, will provide 19VDC back-up for a laptop.

5/9/12/19V DC to DC UPS front and rear panel

AC and Solar Portable Power System (SPS)

Should you require 220V back-up for monitors, printers or any other relatively low-demand device, a slightly more expensive unit (around R4 000) can be used as a UPS and will offer longer run-times than the smaller units described above. These units are completely portable, weighing around 4kg, and have multiple inputs, both solar or 220/230VAC, and 220/230 VAC output as well as 3X USB/1X USB QC3 outputs.

Peak power is rated at 1200 Watts with a Lithium-Ion battery capacity of 396Wh, which should run a laptop, inkjet printer, router and LED lamp for 4 hours. Most notably, if the power outage is during sunlight hours, a 100W solar panel can be connected to extend battery capacity.

These two categories of back-up solutions can be considered as being for “personal” use and whilst there is substantial demand for teleworkers to be equipped with these, they also play a role in many other applications, such as keeping CCTV cameras powered and charging all manner of smart devices such as tablets and laptops. The SPS above can run a small TV and decoder or router for 4 hours, so the application is not exclusively telework related but can also help keep loved ones in contact across the globe by maintaining power to laptops and routers during power outages.

Scaling up to devices that offer longer run-times and the ability to accept heavier current loads but are still semi-portable, a popular category is for 1000 – 1500 Watt units, which employ predominantly deep cycle lead-acid batteries. These batteries are comparatively inexpensive compared to Lithium-Ion although substantially larger, heavier (up to 40kg) and have less useable energy due to Depth of Discharge limitations.

Starting at around R8 000, these units generally use inexpensive inverter/chargers and are most often used to back-up TVs, decoders, routers and possibly one or two low Wattage lamps. The inverters automatically detect a grid failure and switch to battery in around 20 milliseconds, thus it is virtually a seamless transition with decoders not having to reboot.

There is also the option to add solar on some models, which can extend the run-time during sunlight hours.

Lead-Acid based PowerCaddy back-up system

PowerHex Plus Portable back-up system

Moving to more ergonomic and modern semi-portable solutions, the PowerHex is based on more sophisticated inverter technology incorporating a robust transformer to deal with electrical surges and spikes. Additionally, the inverter incorporates such features as temperature compensation and control permitting the use of more sophisticated batteries such as AGM-Gel, which have greater cycle life than ordinary lead-acid batteries. This translates into less frequent battery replacement and hence is more cost efficient.

The unit has a steel hexagonal chassis and integrated telescopic trolley handle at the rear to enable easier movement. An LCD front panel shows the important information such as battery charge remaining, electrical load, etc. The chassis door is lockable to secure the internals from children.

A recent development is the option of a Lithium Ion battery to further improve cycle life as well as offering greater depth of discharge. This is known as the PowerHex Plus; it is approximately twice the price of a PowerCaddy but it must be borne in mind that it has double the back-up run-time and a battery that will last 3 to 4 times longer.

3kW Back-up kit showing 2 X AGM-Gel batteries

An integrated back-up system consists of a few primary components: an inverter, a battery charger (which is often integrated into the inverter nowadays) and a battery bank to store and provide the standby energy. There are other items required which we refer to as Balance of System (BOS), which refers to the cabinets, cables, fuses, lightning protection, etc.

The scale of these systems can be as small as 500 Watts (with regard to the maximum current load the inverter can facilitate) up to Megawatt systems in industrial and commercial applications. To make this article relevant to the general public, we will talk in the scale of residential systems, usually from 1kW up to 10kW, however, there are some residential systems much larger.

When referring to battery or storage capacity, it is expressed in kWh (kilo Watt hours) or kW X time = kWh

Thus if you have a 2kW heater, for example, and you ran it for one hour, it would use 2kWh.

It is important to note that if you have a 1kW inverter and you try and draw 2kW through it, it will trip. This is relevant in calculating your electricity usage and in calculating battery bank capacity required. Using the common size 100Ah (delivers current of 1 amp for 100 hours) 12V battery to calculate the kWh, we multiply the voltage (12V) by 100 to get 1200Wh or 1.2kWh.

In making the decision to install a back-up system, you should always consider an upgrade path for adding batteries, as well as possibly adding solar PV panels to the system at a later stage.

Lead-based batteries are not very flexible in terms of expanding, for example, from 4 batteries to 8 batteries beyond approximately the 6 month period. Once the batteries are older than that, the older batteries will tend to decrease the performance of the new, so this is not recommended.

Lithium-Ion, however, is much more flexible allowing you to upgrade your batteries at any time, not to mention all the other benefits of Li-Ion, namely cycle life, physical size, weight, DoD (useable energy) and faster recharge time. Although more expensive, there is an argument that to install a similar quantity of lead batteries, you would need twice the kWh of Li-Ion.

Additionally, Li-Ion is equipped with a Battery Management System (BMS) that offers a complete audit trail of the batteries’ history. This could be relevant when making warranty claims as it could prove that through no fault of the user, the battery failed.

Your supplier should assist you in making this decision, showing expected cycle life and comparative costs per kWh. Ultimately, it will be your decision and it is preferable to make this decision upfront.

Hybrid Kit with Li-Ion batteries and CIGS solar panels

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Renewable energy procured from private generators as part of the department of energy’s Renewable Energy Independent Power Producer Procurement (REIPPP) programme contributed more than a quarter of the peak-time electricity South Africans consumed during the first half of 2020.

This is according to a report on the performance of renewable energy projects compiled by energy regulator Nersa.

This news comes as the availability of Eskom’s fleet deteriorated to just over 60% in the last week of November, according to the latest data published by the state-owned utility. This is partly the result of an increase in plant taken offline for maintenance, but unplanned outages remain very high.

In the week ending 29 November, 18.48% of Eskom’s generation capacity was unavailable due to maintenance and 18.08% due to unplanned breakages.

In the week ending 29 November, 18.48% of Eskom’s generation capacity was unavailable due to maintenance and 18.08% due to unplanned breakages

The average availability factor for the year to date is 65.65%, which is considerably lower than the almost 67% in 2019. The norm is 80% availability, with 10% taken out of service for planned maintenance and 10% for unplanned maintenance.

Eskom’s forecast to 1 March 2021 shows that it is likely to have a consistent supply shortage of more than 1 000MW in all but one week. It indicates that the country could suffer stage-2 load shedding for most of this period.

Clearly helping

While electricity demand in the first half of the year was distorted by the Covid-19 lockdown, renewable energy clearly helps Eskom to limit the use of expensive open-cycle gas turbines or keep it from instituting load shedding during the morning and evening peaks.

According to Nersa, 68 of the contracted 112 projects were in commercial use with a combined generation capacity of 4 283MW. The regulator expects a further nine projects to be in operation by the end of the year, which will increase the total capacity to 5 048MW.

Although the performance of the different technologies is not comparable, it is useful to note that the combined installed REIPPP capacity will by the end of the year exceed the nameplate capacity of Medupi, of 4 764MW.

Nersa reports that non-REIPPP renewable projects, aimed at own use or generation for a specific client, adds a further 823MW to the country’s renewable capacity. It has also approved the registration of small-scale embedded projects with a combined capacity of 72MW. This is mostly solar photovoltaic energy.

Nersa says the increase in renewable generation has resulted in the geographical diversification of power generation. The dependence on coal in the northern parts of the country has been diluted, with renewables spread through the Eastern, Western and Northern Cape, closer to the demand. This means that electricity losses associated with long-distance transmission can be reduced.

Renewable energy will be even better utilised during peak demand periods if the storage capacity is increased, according to Nersa. Currently only six concentrated solar plants have storage capacity, varying between two and nine hours.

Renewable energy will be even better utilised during peak demand periods if the storage capacity is increased

Nersa expects that increased storage capacity will, by 2022, enable renewable energy that is generated when demand is low to be utilised during the peak.

Eskom has in fact embarked on a big storage project.

Nersa reports that Eskom paid independent renewable power producers R14-million in 2019/2020 in terms of the take-or-pay power purchase agreements for energy it was unable to take.

During the first half of 2020, Eskom paid on average R2.23/kWh for renewable energy. Nersa expects this number to come down as projects contracted later at lower tariffs come into operation.

This article was originally published on Moneyweb and is used here with permission

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Solar is good for your wallet

• For the period 2002 to 2019, electricity increased by a staggering 500% in South Africa.
• Future annual increases could be in the region of between 15% to 20% compounding year on year.
• Municipalities are starting to permit the “feed-in” of surplus electricity that you might generate thereby giving you a credit on your electricity account.
• Loadshedding is set to TRIPLE in frequency and severity within three years (CSIR Report). The battery component of a hybrid system ensures your lifestyle is not affected by power outages.

FACT: Electricity produced by solar panels costs R1.20/kWh right now compared to R2.30/kWh for grid power

Solar is unbeatable as an investment vehicle

The current return on investment per annum on R100 000 is around 5.5% for property, 6.89% for SATRIX and around 6.25% in a call account. Thanks to Eskom’s devastating price increases, you can invest that same R100 000 in a PV solar system (enough for a 5kW grid-tie) and you’re looking at returns of 40.7%.

FACT: A solar system installed in your home can add around 5% to the selling price.

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AVAILABLE ON BACKORDER HERE: Ratel 8100 Micro DC-to-DC UPS

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The choice to provide your own electricity is, however, within your control and the use of solar power is becoming inevitable and, financially, a complete no-brainer. A small installation for a domestic household to supply 3 kWp (kilowatt peak) of solar panels along with 7kWh lithium battery would cost R170 000 installed.

A system of this size would produce 450 kWh per month resulting in savings of R10 470 in year and these savings would increase in-line with the Eskom increases: if there is a 10% increase in the second year, the savings would increase to R11 500 and so on. Most significantly, the batteries would provide the energy storage to allow you to use the energy created in the day during night-time hours as well, as providing back-up for the very annoying, and now costly, power outages.

As a direct comparison, 1kWh from Eskom is currently R2.30, whilst 1kWh of solar from the above system would equate to R1.54. A 450kWh system is generally not large enough to take you totally off-grid in an average 3-bedroom house, but it does take care of approximately 50% of your usage.

As we are using a residential dwelling in the example it is interesting to note that even a bond of R1 000 000 would have cost R9 900 per month in repayments in February 2020. With the 3% decrease in the repo rate, that same bond repayment is now R8 100 per month.

Many of the large financial institutions have flexibility in their offerings and certainly where you are seeking to improve your property by adding solar and standby power, they may be amenable to adding the cost to the existing facility. Thus, rather than laying out R170 000 in cash, which you may not have, you could use the now comparatively inexpensive bond facility to procure a hybrid solar system with batteries.

The repayments could be offset, at least in part, by the savings on your monthly electricity account and the value added to your home is significant as many buyers are now looking for homes with energy and water efficiency.

A hybrid solar/battery system will amortise in approximately eight years, where after your 450kWh is free.

The choice to move to renewable energy used to be predominantly about eco-friendliness, but with the exponential growth in solar, the solar choice is a matter of economy for all homes and businesses. The addition of batteries to the system becomes more important as many of us now work from home and power outages affect our productivity, security and overall lifestyle.

You DO have the power to choose – connect with Sinetech through the enquiry form below and start your own journey to energy independence:

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One has to be sensitive to the unions demands though, as the majority of the workers have worked hard in difficult conditions over the past year and it is patently unfair that they should suffer the financial impact of the previous regimes blatant corruption. That said, when you are already R350-billion in debt, as Eskom are, it is not sustainable from a business perspective to be giving staff increases at all, and certainly not 9% which exceeds CPI. This is really Hobsons choice for Eskom as if they capitulate and accede to the unions demands, the death spiral they are in, will surely accelerate. Conversely, if they stand their ground, rolling mass-action is a very real possibility and load-shedding in an order of magnitude not yet seen, will prevail.

Lets take a closer look at the latter problem, which is problem 1- Continuity of Supply of electricity. Many things can cause a hiatus of the grid from excessive load demand, equipment failures, cable theft, weather events, strike action, coal shortages all the way to sabotage. The reality is that whilst “load-shedding” is top-of-mind for many South Africans, we have seen very little load shedding of late, simply because Eskom generally have excess electricity supply.

This in itself may sound comforting, however, the over-supply is due to the exit of many large users- smelters, mines etc. over the last decade. This is part of what ails our economy and has contributed to the steep increase in unemployment and commensurately, an increase in crime. One of the primary reasons for the exit of these industries is the high cost of production which is problem 2 – Electricity Tariff . Add to this, unreliable electricity supply and the impact that has on an aluminium smelter for example, and it is clear to see that here are other geographies much more appealing to operate in for these companies.

It is also a fact that since 2009, electricity production by Eskom has actually dropped by 9%, however the cost has increased by 210% in that period for domestic users and looks set to increase by between 15% to 25% per annum going forward. Predictions show that by the year 2020, only 2 years away, we will be paying as much as R3,73 per kWh, more than double the current rate of R1,80 per kWh beyond first 600kWh used. Current rumours suggest a 16% increase this year and a staggering 31% next year.

A big portion of this increase is through the Regulatory Clearing Account (RCA) which permits Eskom via NERSA to clawback any losses due to reduced sales or increased costs – wish I could get that in my business. “How about we approve a budget but if we don’t make it, we just make our customers pay it anyway”. The RCA number of R66,6 billion was approved by NERSA and will mercifully only be implemented over a number of years.

The chart below sketches where we are going in terms of electricity tariffs.
Thus we only have two problems, reliability of supply and exorbitant prices, please forgive my euphemizing of the situation but sometimes you just have to bury your head in the coal…sorry, sand.

Having sketched a rather bleak picture, I have to pay tribute to the new management team at Eskom who must be some of the most courageous and dedicated South Africans and who are certainly not doing this for the money. Hats off to them for taking, in rugby parlance, the hospital pass. If this team can’t succeed then I doubt anyone can but they will have to make some very tough decisions as far as personnel goes. But that is not the heart of the problem as staffing costs only make up 10% of Eskom’s annual expenditure. The largest slice of expenditure, 75%, is in procurement and plant infrastructure, thus, that is where the significant savings can be made.

The question our “dream team” have to be asking is, “what, as Eskom, is our business?” Electricity Supply Commission, with the emphasis on “supply”. Modern business models are premised on focusing on components of the value chain that you do best or are the most profitable, other bits of the value chain can be fulfilled by partners who focus on excellence and scales of economy better than you can.

A parallel could be drawn between S.A. Breweries owner/driver program implemented in the 90’s which saw their existing drivers becoming owners of the trucks over time, thus reducing SAB’s burden of operating fleets of trucks and empowered their loyal employees to participate in the value chain as business partners.

This kind of thinking is the direction that Eskom need to be moving in to optimize their value chain without compromising their work-force.

There is however only so much one can save by using these efficiencies and thus we need to look at alternative ways of generating power such as solar power. South Africa has one of the best irradiance factors on the planet and it makes sense that we should use this sunlight to power our buildings and homes as much as possible, as long as it is affordable.

Previously, photovoltaic solar or PV Solar was quite expensive and thus not widely adopted other than in environments where no grid existed. In the last three years alone, PV solar has decreased in price by over 50% as adoption increases, rather like computer technology. Similarly, the performance of solar panels has improved substantially in the last period as more research and development dollars are invested in advancing the technology.

A solar installation is comprised of two major components which is the solar panels and an inverter, which converts the DC electricity delivered by the solar panels into AC power. There are two distinct types of solar installations, namely Grid-Tied or Off-Grid. Grid-tie solar as the name suggests is where the electricity grid exists and the inverter is connected to the grid and matches the frequency of electricity delivered by the grid into your premises. Off-grid is where no grid exists or the customer has elected to have a completely separate system using only solar panels an off-grid inverter and a battery bank to provide power during hours of darkness.

A Grid-tie system (example below) is the most commonly used system and is used for generally for one purpose, to reduce usage of the electricity grid during day-time hours. The obvious benefit of this is lower electricity bills but there is also a benefit in terms of reducing carbon footprint which in the coming years will also translate into money as carbon taxes are intensified. It is also possible to generate income in the form of credits in certain municipalities from doing “grid feed-in” where excess energy generated by your solar plant can be fed into the electricity grid and be credited to your account. Where this is not permitted, “grid-limiting” is usually invoked within the inverter so as to make sure that current is not fed into the grid illegally.

Off-grid systems (example below) use a different kind of inverter and usually have an associated charger and batteries to store energy. These types of systems are typically used in rural areas where there is no grid access and are particularly popular for farms, game lodges, clinics, schools and other premises that depend on electricity in remote areas.

There is a third alternative and that is the Grid-Interactive or Hybrid system (example below) which combines both Grid-tie and Off-grid operation, historically, this was achieved using two separate inverters.

The advantage of the Grid-Interactive is electricity savings plus back-up facilities with two sources to charge the batteries, both solar and grid power. The disadvantage is the cost of installing two inverters thus Hybrid Inverters were introduced to facilitate both systems in one inverter. This also allows scalability of your investment whereby you can phase-in either back-up first followed by grid-tie or the reverse. This will reduce the cost of the initial phase by obviating either the solar-panel component or the battery component.

As can be seen, there are numerous ways to solve our two big problems of grid reliability and tariffs but is it worth it? From a reliability perspective one has to assess the inconvenience or in the case of a business, the lost revenue and productivity caused by power outages which can be directly quantified. Many businesses rely on generators to provide continuity of power and certainly there is a place for diesel or petrol generators even Eskom use mega-litres of diesel per annum running generators. Therein lies the problem, with the ever-increasing cost of fuel, generators can be expensive to run over long periods. Many installations now use a combination of generator power coupled with battery stored power to provide back-up. Batteries, like solar panels are reducing in cost and physical size making them more attractive than generators alone.

The tariff issue turns on “grid-parity” the point at which solar energy is equal to the cost of grid energy. We are way past that point where solar is substantially less expensive than grid-power once you move into the second tier of tariffs.

By way of example in a recent proposal to a small manufacturing enterprise for 30kWp Grid-tie system, roughly 100 solar panels, the capital outlay was approximately R450,000 with a payback period of 3 years and 7 months and savings of R13-million over the 25 year life of the system. The savings are based on the conservative assumption that from year 1 to 5 Eskom increase by 15% p.a., year 6 to 15 by 12%p.a. and the remaining 10 years by only 8%. I am sure you will agree that this is conservative, however for the purposes of this projection, we look at best case scenario.

The payback is assisted by application of Section 12B of the Income Tax act which permits the depreciation of 100% of expenditure on renewable energy assets in year 1 for commercial enterprises. Alternately, Sinetech offer a rental scheme for businesses minimizing cashflow impact, reflects off balance-sheet and minimizes technology risk as a refresh is permitted after five-years.

Solar and standby power is set to become as commonplace as other technologies such as fibre-to-the- home, cable TV and other contemporary technologies. Ironically, all technologies depend on electricity and yet conventional electricity is becoming unaffordable and is not as reliable as we would like. Similarly, many South Africans still do not have electricity in their dwellings which can be solved quickly and comparatively inexpensively using solar power.

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Once our illustrious National government realized the impact this folly (which they were forewarned about in 2003) would have on our country and its long term economic future, it was too late. Mines, manufacturers, resource processing plants and many other manner of high-volume electricity users had throttled back and in some cases, shut-down plants and have sought greener pastures.

Earlier in May 2016, our illustrious Number One, expressed his “happiness and excitement” for the achievement of the end of load-shedding in South Africa on a recent visit to Megawatt Park, Sunninghill. He proudly announced that Eskom was in fact so overstocked with electrons that they were now in a position to export to our neighbours. He also mentioned how happy the Eskom employees were, which is little wonder when the average annual salary at Eskom is R630,000 or R52,500 per month. I am fairly sure that the labour force out at the various power stations are not earning anywhere near that, which means Megawatt Park employees are, in fact, smiling all the way to the bank and not because of the end of load-shedding.

Although Eskom would like to attribute the absence of load-shedding as an achievement of their turnaround plan, the majority of this “success” is due to a massive drop in demand. It is estimated that approximately 10% of the total demand was wiped-out between 2013 and 2015. Luckily for Eskom, because their electricity production capacity also dropped from 37,745MW to 34,345 MW.

In effect, Eskom have been successful in avoiding declaring the reality of the dire circumstances through:
1) Load-shedding – A schedule of planned and communicated electricity outages to reduce the load on the overburdened grid.
2) Price increases- The price of electricity has more than doubled from 2008 to 2015 from 19c/kWh to 48c/kWh.

Large customers have gone elsewhere, South Africa’s economy is in its worst condition in decades and Pretoria are patting themselves on the back for ending load-shedding. Sadly, whilst load-shedding may be dead and gone AS A POLICY, I don’t believe that unscheduled power cuts can ever be declared impossible. In my view this is political rhetoric merely playing with the semantics of “load shedding”.

Suffice to say that in the Johannesburg region, we currently experience 11 power outages (NB. Not load-shedding) per day. Admittedly, some of these involve only one or two streets, however some are quite widespread as we saw this last weekend 20-22 May 2016, where a vast area of Johannesburg experienced long periods (in excess of 5 hours) without power. One area in Bryanston has now been without power for two days due to a transformer failure, no doubt it failed as a result of inadequate maintenance.

In effect, we as the consumer have gone backwards as a at least with load-shedding, you would be advised in advance and the outage period would be more or less in line with the prediction. Now, the outages are as and when something fails or the utility decides to summarily cut the power. Any attempt to establish the duration and cause of the outage from your friendly call centre will be met with routine vagueness.

It is inevitable for any power utility across the globe to have a maintenance backlog, usually due to budgetary and human resource constraints. In 2008 the backlog expressed in monetary terms was R27,4 Billion and has grown to a whopping R68 Billion in 2016. This, in a utility that is in fact producing less electricity than in 2008 down by approximately 9% in 2016 and the price per kWh up by a staggering 152%.

The above graph is a lesson in unsustainability in the electricity business, sharply declining production against what should be an ever increasing demand. Similarly, exponential price increases far in excess of the inflation rate. Appears electricity is becoming an LSM6-10 luxury commodity if one looks at this trend, perhaps Eskom should consider privatising into Richemont alongside their other premier brands like Cartier, Mont Blanc etc.

Thankfully, we as South Africans either make a noise or make a plan depending on your cultural background. We have been making a lot of noise for a long time, witness the ongoing service delivery strikes, but it seems Pretoria have other more pressing issues of an internal nature and thus respond with more empty promises.
So we are left with the only other option, and that is to make a plan to provide our own energy, which in essence implies solar energy for most small scale applications. However, the applicable legislation is as follows:

The Small Scale Embedded Generators (SSEG), in this case Photovoltaic solar panels with inverters etc, national standards have yet to be published and are more than 12 months overdue. The Department of Energy and NERSA are in the process of defining these standards and for very good cause. Should they have not been diligent in this process, then any sub-standard equipment could be connected to the electricity grid with potential disastrous results.

The disasters referred to could extend to a disruption of the electricity grid on a national basis or even the potential injury or death of utility technical personnel performing maintenance on the grid. Illegally connected “generators” could still be generating power, so albeit the system has been shut down, power could still be present, resulting in some severe consequences.

Additionally, there is currently no revenue recovery mechanism in place, thus any power you put back into the grid will just be absorbed with no benefit to you. In fact, in some instances the power you put back into the grid can be added to your bill.

This applies only to grid-tied systems and mercifully, we can employ point 2 above for “own use” in the interim and hopefully, during the course of 2016, the SSEG standards will be published. This will allow connection to the grid with some form of recompense for the power you put back into the grid and don’t use. The real attraction of being grid-tied, is that effectively, you use the national grid as an energy storage device rather than having a bank of batteries to store power generated by your solar panels during the day. This is the theory at least, however, the tariffing of what the utility will pay you for your power is also to still be defined in SSEG.

Having briefly set the scene from a “current state-of-play” perspective, it is clear to see that we have an electricity volume problem, despite current political sound-bites and we have ever-burgeoning increases in electricity pricing. Therefore, we need to explore ways to mitigate power outages, previously known as load-shedding and we need to find a way to reduce monthly electricity bills. Both of these requirements can be met with a Standalone PV Solar System, but where do you as a domestic or commercial user start?

Standalone PV Solar System

Any decent PV solar company will advise the prospective client to firstly reduce their overall load or electricity requirement by replacing at least the most regularly used lights in the building with LED or CFL globes. Lighting in domestic applications makes up to as much as 25% of the total electricity bill and by using a 7W LED globe you can obtain approximately the same amount of lighting as conventional 50W incandescent globe. Admittedly, LED globes are expensive, however they not only use less electricity but also last up to 10 times longer than CFL globes and as much as 40 times longer than incandescent globes. The company proposing your PV solar solution, should do these calculations for you once you have identified the relevant lights used to show potential savings.

The second area where substantial savings can be made is with water-heating, the average household uses 35% of their total electricity consumption to run electric geysers. Whilst solar water geysers are comparatively expensive, like LED lights, they amortise themselves in approximately 3.5 years. Thus by spending R20,000 on a solar water geyser today may seem expensive, calculate what one-third of your electricity bill is to see if it makes financial sense.

The next logical step in the process, having reduce your overall electricity usage, is to conduct a power audit at your premises. This will involve installation by the proposing PV solar company of a monitoring device for a period, recording the average and peak demands. Having measured this after the installation of the LED lights and the Solar Water geyser, the sizing of the solar or standby system will be substantially smaller and hence less expensive.

Once a peak-demand baseline is established, the PV solar company will conduct a site visit to establish the physical dimensions of your roof area, dimensions and distances of inverter/battery placement and connection to your electrical Distribution Board (DB) as well as considerations such as slope of roof angle, directional bearing of the proposed roof and multiple other parameters.

From this data, the solar company will develop a custom design that suits your specific building and power requirements. All too often we get asked the question “How much will it cost for me to go solar?” This is a very dangerous question to answer because, albeit that you have a 300 sqm house, with mom, dad and 2.5 kids, your particular energy usage is unique, even if the house next door is identical with the same occupants, their electricity usage can be substantially different. Similarly, the neighbours long term objectives could be different to yours, you may wish to get off the grid completely, whereas they may only wish to reduce their electricity bill by 50%. Some clients don’t even want to deploy solar initially, merely provide a back-up solution for power outages (remember Load-shedding is dead and gone, yeah right).

Back-up System

The schematic above refers to the simplest iteration known as a Back-Up System, an inverter and battery bank that is installed in-line to the distribution board of the home or business. This system effectively takes grid-power and stores it in the battery and monitors the presence or absence of grid-power. Should the grid fail, the system automatically switches in roughly 20ms to the battery bank and continues to provide power from the batteries. To contextualise the switch-over time, you will not even notice that you have switched to back-up power, and for rugby fans, DSTV does not reboot, so you won’t miss the match winning try. Naturally, this would be less-expensive as there are no solar panels present, however it is advisable to design the Back-Up System for scalability to allow for the addition of solar later.

Upon conclusion of the design , the solar company should provide you with a firm quote itemising all of the various system components and related services, such as installation, commissioning and maintenance. That old Latin warning applies “Caveat Emptor” or Buyer Beware. The selection of products and quality of the services will make a world of difference to how your solar system ultimately performs. The following are some questions you should ask:

Solar Panel Considerations

• Can the roof carry the additional weight of the proposed solar panels?
• If this has not been considered in the design, show the fellow the door.
• Is the mounting system for the panels non-penetrative?
• Sophisticated mounting systems obviate roof damage and hence leaks.
• What is the corrosion guarantee of the mounting system?
• Expect at least a 10 year lifespan.
• What risk is there of lightning damage and what can be done to mitigate this?
• Robust earthing is essential, however, you may add further lightning protection but it costs.
• Are the solar panels being proposed Tier 1 panels and what guarantee do they have? The answer should be yes and the guarantee should be 25 years.
• What is the linear performance guarantee, ie. what output degradation should be expected over the 25 year lifespan.
• Yield should be 80% or higher at the 25 year mark, thus about 0.4% per annum.

Inverter Considerations

• Confirm that the inverter size ie. 4kW, 10kW is adequate to serve your electricity load.
• Click here to download our “Appliance Calculator” to help you size your load.
• Ensure that the inverter proposed is a pure sinewave inverter.
• Modified sinewave inverters can be problematic with some appliances such as LED TV’s.
• There are 72 different inverter manufacturers products available in S.A. make sure the supplier and manufacturer have a good reputation and installed base.
• Names such as SMA, Outback, Omnipower, Victron and Studer are well established brands and most carry local NRS approvals.
• Does the inverter make use of transformers internally?
• Inverters that employ transformers are usually more resilient to power spikes etc.
• What is scalability of the inverter, both in terms of connecting serially to more inverters as well as the possibility of doing both off-grid and grid-tie ie. hybrid inverters.
• Some inverter manufacturers are offering hybrid inverters meaning the inverter can be grid-tied as well as offer off-grid functionality ie. excess power can be returned to the grid or stored in batteries by one single inverter. Previously, two separate inverters were required. This also allows flexibility of functionality in that you could start with having a simple backup system with batteries, no solar panels to cater for power outages and then later add the solar and grid-tie component. Alternately, one could start with grid-tie and solar, no batteries and then at a later stage add the back-up component of your own battery bank, all using one single inverter.

Grid-tied PV Solar System with hybrid off-grid functionality and Back-up

Battery Considerations

As described in the previous paragraphs, batteries are technically only needed for back-up and power storage in scenarios as follows:

• When you are effectively “tanking” power from Eskom into the batteries to provide power when there is a failure, thus, pure back-up. No solar panels are in installed in this scenario.
• When you are in an area where there is no grid power at all and you therefore use solar power during the day and store any excess in the batteries for use at night. Typical in a rural scenario.
• Where you have grid-power and have solar panels to reduce your Eskom bill plus battery back-up to provide power when Eskom has an outage. This scenario may also become relevant where you are putting excess power back into the grid at say 50 cents per kWh credit but then having to pay R1,50 per kWh when you use that power at night. It may be more cost effective to store your anticipated evening power demand in batteries first and once they are topped up, then feed the excess power into the grid for credit. We will only know these realities once NERSA’s SSEG initiative has published their standards and the related net-metering tariffs ie. what you earn back in credits and what you pay.

Source: Bloomberg

Bear in mind that albeit that you pursue solar power to reduce your bill and the demand on Eskom, your carbon footprint etc. you will be charged an additional surcharge for that pleasure. This is to protect the coffers of local municipalities who derive the bulk of their income from selling electricity which, apparently, they often don’t pay Eskom for, hence another reason for the crisis at Eskom.

The emotional response to this is “I want to get off the grid completely” and we as a company would be more than happy to help you with that, however, it would be difficult to make the business case in most instances. Providing a complete off-grid system requires accurate analysis of your particular usage plus we would have to factor in adequate storage for a suitable “autonomy” period ie. when there are cloudy or rainy days and limited sunlight, the battery banks would need to be substantial.

The sensible approach to take would be to provide a solution that is designed for self-consumption today ie. independent of the grid BUT carries all the necessary regulatory approvals and the technical scalability for grid-tie later. This would either be a standalone back-up system comprised of an inverter and battery bank or alternately the next step up, the standalone PV Solar system which would see the addition of several solar panels. The latter system would have the added benefit of providing some of your power requirements for both your household or business load as well as charging the batteries but would put no power back into the grid.

We all are already using solar in one form or another, just not in the scale or manner that we will in the future. Unlike fossil fuels, solar does not have a peak limit and is not a limited resource, thus more comparable to silicon chip technology. With ubiquity comes price contraction and in turn wider acceptance resulting in further funding of R&D and greater performance from solar panels.

Source: Bloomberg

Not convinced yet?

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This test facility was established to ascertain the performance of the various solar technology types in the Gauteng area under specific atmospheric conditions. These conditions are constantly measured by a comprehensive weather station and this data, together with the performance data of the three different technologies (ie. monocrystalline, polycrystalline and CIGS), is recorded by the management station.

Chris Rodgers, CEO of Sinetech, comments “We installed the test-bed just over 2 years ago really to ascertain solar module performance in local weather conditions. Naturally, we had to deploy the three technology types that we offer and within a short period of time, we noticed that the CIGS technology was outperforming the other two technologies. The only drawback at that stage of the CIGS technology, was that it required more roofspace to accommodate a 3kW system than the comparable mono or poly 3kW system.”

Actual Data depicting approximately 300W greater yield for a given day

Sinetech have for many years been distributors of the Solar Frontier SF range of CIGS modules; however, Solar Frontier recently withdrew from international markets to focus solely on their domestic Japanese market. CIGS technology has been in development since 1975 and for the first 30 years of its life, battled to compete with silicone-based solar panels from a performance perspective.

During the past five-years CIGS has seen significant performance growth whilst conventional silicone technology has been reaching a plateau. PERC (Passivated Emitter and Rear Cell) technology, one of the most recent enhancements in silicone module development, renders only roughly 1% more efficiency in performance. For clarity, efficiency is the cells’ ability to convert light into energy, anything in the low 20% range is considered very good today.

Rodgers continues “Efficiency is a bit of an academic number, as typically the numbers quoted are produced in lab conditions or are a snap-shot of optimum performance. The aspect that we should all be interested in is how much electricity our solar solution will yield over time. After all, we really only invest in solar to save money, save the planet or because we have no alternative source of electricity … but mostly to save money.

“Comparing our three 3kW systems in our test-bed, the CIGS system delivers a yield (total annual energy generated per kWp) of 13% more than the other two technologies. On the basis that the prices of the three technologies are more or less the same, the savings offered by the CIGS are thus 13% higher. This means a faster ROI which will make the CFO happy, and the reasons for this will make everyone happy. The greater yield achieved by the CIGS panels is attributable to the technology being more resilient to heat, so while the performance of silicone panels will degrade substantially on a hot day, the CIGS panels can endure higher temperatures with minimal performance loss. Additionally, the CIGS technology is much more resistant to shading or low light conditions and continues to make power where silicone panels cannot. Over time, this resilience adds up to a whopping 13% better yield.”

“We believe that there are many cases where CIGS technology makes optimum use of the customer’s investment, and this is why we remain committed to the technology. This is not to say that it is appropriate in all scenarios or that we will cease to offer silicone technology, however, we believe that each installation should be decided on its own individual merits. For this reason we have secured the agency for the Eterbright range of CIGS solar modules, which range from 100W right up to 350W, thus overcoming the additional space requirement issue. We have already installed the 335W modules into our test-bed some 3 months ago with excellent results” Rodgers concludes.

Read More about the Sinetech Rooftop Solar PV Panel and Weather Reference Station here:

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