Drinking water is becoming an increasingly scarce resource in South Africa, and Gauteng has been hitting the headlines most recently due to the number and duration of water supply interruptions being experienced. Interestingly, the water shortages are not so much because of inadequate raw water supply from the storage dams, but because of failing supply and delivery infrastructures within the cities. The failing infrastructures are, however, having a significant negative impact on the storage dam reserves.

A common industry benchmark to measure the efficiency of the water supply network is the percentage of Non-Revenue Water (NRW) that is lost before delivery to the consumer. The losses are typically due to leaks, theft, and metering faults.  Most provinces lose more than a third of their water supply. The international benchmark is below 30%, and only the Western Cape is inside the benchmark at 29.6%.  Gauteng is second best at ~40% – the rest of the provinces are far worse.

The purpose of this article is not to look at the greater supply issues and the NRW challenges faced in the cities, but will look at the water use on the consumer side of the meter – particularly at schools.

Schools are large communities and the primary need for water is for healthy sanitation. The basic water consumption for the school’s operation is quite easily modelled based on the pupil and staff complement at the school. A study was conducted in 2004 for the Water Research Commission at a number of Gauteng schools. In the study the water usage in Ekurhuleni schools ranged between ~3 and 113 litres per learner per day, and the average was 23 litres/learner/day. Following a water saving initiative at the time that included repairing leaks, replacing washers, modernizing toilet cisterns to dual flush, replacing automatically flushing urinals with manually operated push button systems and replacing conventional taps with push button taps, the average water usage dropped to 12 litres/learner per day. There was quite a large range in perlearner consumption of water, but all schools successfully reduced their consumption.

School facilities and amenities are major drivers for the total water demand. Landscaping and sports field irrigation can be significant water users depending on the season and the rainfall pattern.

Sports fields, which are typically 6000m2 each, require 25 mm of precipitation per square metre per week during the growing season. This equates to ~ 600 kilolitres of water per field per month.  Thankfully, Gauteng is a summer rainfall area, and sports fields are not always dependant on the municipal supply.

Swimming pools are large users, or losers, of water. The typical 25-metre school swimming pool has a surface area of five hundred square meters and a volume of about 800 000 litres. The typical water evaporation rate in Gauteng is five millimetres per day. Five millimetres evaporation is five litres per square metre per day, i.e. 2.5 kilolitres per day from a typical outdoor 25-metre school pool. Swimming pool maintenance requires backwashing of the filtration system on a frequency dependant on the swimmer numbers and frequency will vary seasonally – typically it is a monthly requirement and will dispose of 15 kilolitres of water per occurrence.

So then, collating these benchmarks, we can build up an estimate for a monthly water usage profile of a school. Let’s take a look at a modelled day school with a learner complement of 900, and staff of 100; one grassed sports field; and an outdoor 25-metre swimming pool.


* In this simple model for now we assume no on-site boarding or live-in scholars.

Every school will have its only benchmark based on the facilities and the activities at the school. The benchmark illustrated here is probably a peak benchmark, and it will vary seasonally. The adage of what is measured can be managed, and comparing monthly water billing to a calculated benchmark will provide some comfort to the school of being under control or raise the alarm that there is water loss, and an associated cost.

Water is a vital resource but also a significant expense for schools and universities. Many educational institutions fail to realize how much cost they can save by reducing their water consumption and improving water management and efficiency.

Water and sewer tariffs are increasing and, no doubt, will start following the electricity escalation trend. Bear in mind that municipal billing assumes incoming water is also outgoing water, i.e. the sewer tariff is applied to the incoming water volume – water used for irrigation and loss due to evaporation is billed in the sewer billing.

Either way, this typically means schools and universities must expect to pay much higher rates for water and sewer services in years to come.

There is good news though. There are ways administrators can reduce or mitigate these cost increases. The answer is water efficiency.

Understanding Water Efficiency

Some of us may wonder what the difference is between water conservation and water efficiency. Water conservation refers to reducing consumption briefly, such as during a drought.

Water efficiency, on the other hand, means reducing water consumption permanently, often by turning to technologies designed to use less water. For example, the use of pool blankets /covers can assist in not only reducing evaporation losses, but also the loss of heat in the case of heated pools.

We should note that how water-efficient an organization is assessed to be can also be an indicator on the inherent efficiencies of the organization in other aspects of its operations.

Water waste and other environmental waste are signs of inefficiency in [an organisation’s] production and management.

How to Start

To start the process of using water more efficiently, administrators must collect two or three years of water utility bills to determine how much water the school uses and what it pays. Now, we have a benchmark against which to mark our progress. From here, we take the following steps:

Administrators should set water-reducing goals versus the theoretical benchmark discussed earlier in this paper. Water reduction over a defined period of time. Having goals helps keep the journey focused.


We reach those goals by conducting a water audit to determine exactly where water is being used on the campus.


With the audit completed, the deviations from the theoretical benchmark will highlight the areas of opportunities – for example, landscaping and restrooms.


Among the steps administrators can take to reduce water consumption for landscaping and vegetation, the following are noteworthy initiatives :

  • Install native vegetation. This refers to plants, trees, shrubs, and other vegetation customarily found in an area. 
  • Ensure plants are clustered; bunched together, they save water.
  •  Reduce mowing frequencies; set mower blades higher to help keep the soil below moister.
  • If sprinklers are installed, ensure they are on timers and do not irrigate nearby sidewalks and streets.


A few initiatives with toilets and urinals can bring surprisingly meaningful results. Newer dual-flush toilets are mandated to use 9 litres per flush or 5 litres per half flush. However, as toilets age and undergo repairs, they may use more than these amounts.

Administrators should replace toilets every six to seven years. This replacement will help ensure lower consumption, and many manufacturers are now making toilets that use less than the 9 litres of water per flush.

New urinals must use no more than 4 litres of water per flush. However, due to purchasing and cost factors and a desire to reduce water consumption even further, many facilities are taking the next step and installing waterless urinals.

These systems use no water, require less plumbing, do not require flush handles or sensory flush systems, and have few, if any, service requirements, all of which make them more cost-effective to install and use.

The Next Step is Yours

Let’s remember that there are ways to reduce water consumption in schools, universities, and all facilities. The technology is available and constantly improving. The next step is yours: take the steps discussed here and realise the savings.



Facing load shedding, South African businesses are turning to alternate and renewable energy solutions like grid-tied solar PV systems to reduce their carbon footprint and gain independence from the grid and pursue security of supply. Load shedding presents unique challenges to businesses already equipped with grid-tied only solar PV systems. This article briefly explores the intricate dynamics of how load shedding affects such grid-tied only solar PV systems.

Grid-tied solar PV systems are the most prevalent, simple, and cost-effective solution compared to off-grid and/or hybrid solar PV systems because they can operate without reliance on energy storage equipment. Grid-tied solar PV systems are simpler to install, realise attractive energy cost savings and are thus the most accessible option readily deployable for businesses.

A grid-tied Solar PV system is reliant on the grid’s availability to fully and properly serve the demands of a customer’s facility, meaning that when the grid-tied Solar PV system is not producing enough power to serve the attached load, supplemental power is then drawn from the grid to meet the total site electrical demand. Unfortunately, when the power fails from the utility’s side, the grid-tied Solar PV inverters will switch off for two reasons:

  • A grid-tied Solar PV inverter, which is a current-source device will have no reference voltage or grid to inject its power into, the solar PV inverters thus cannot operate. (A hybrid grid-forming Solar PV inverter by comparison is a voltage-source device and does not require to see or detect a grid to operate and will form its own grid without regard to the conditions of the attached equipment and any reliance on a grid interface).
  • Safety – if the utility is working on the upstream grid for repairs or maintenance, it cannot have connected energy sources from external systems touching the grid.

These technical requirements and capabilities impact businesses equipped with grid-tied only systems during loadshedding.

Many commercial and industrial (“C&I”) solar PV systems in South Africa are grid-tied. Converting these grid-tied solar PV systems to a hybrid solution is often technically and commercially challenging and requires full and careful consideration for the appropriate scoping of equipment sizing and capacity, along with a full and careful consideration for the type of electrical load at the business premises or facility.

South Africa experiences on average 4.0 to 6.3 hours of peak sunlight per day where PV modules generate the bulk of their output. The figure below shows a grid-tied solar PV system harnessing solar energy during daylight hours when the sun is shining and captures two instances of load shedding.

The impact of loadshedding and the consequential losses is most severe when load shedding takes place during peak solar generation hours.

The impact of load-shedding on these operations has in the past year (2023) shown an average overall impact and loss in energy production of about 20% and Eskom is unlikely to improve the situation in the short-term without a serious and continued intervention and integration of renewable and other energy generation sources into the national grid. Whilst the magnitude of loadshedding is well known, the unpredictable nature of load-shedding and the times in which it occurs makes accurate financial modelling and optimisation of battery solutions difficult and its related financed solutions challenging. Businesses are thus earnestly pursuing conversions to diesel generator integrated and/or battery storage solutions to still be able to harness the solar energy, realise the commercial benefit of the installation, and mitigate against these impacts.

In summary, loadshedding leads to a loss in productivity for grid-tied only solar PV installations and thereby compromised project financial returns. This means that backup sources of power like standby emergency diesel generators need to be purchased, increasing the consumption of fossil fuels, increasing the business’s exposure to volatile fuels costs, and contributing to environmental pollution. Investing in energy storage solutions like batteries to store surplus solar energy and provide backup power during grid outages is increasingly being considered as these storage costs also continue to decrease.

In conclusion, many businesses that have invested in grid-tied solar PV systems, had chosen a sustainable and cost-effective energy solution, realise energy cost reduction, and supplement their fossil fuel energy consumption with green energy. As early adopters of green and alternate energy they have realised the benefits of having made this move. However, during periods of load shedding, reliant on an always available grid, these businesses now find themselves at times incapacitated by the failing grid, disrupting operations and thus being compelled to augment their existing installations with energy storage and generator solutions at a greater expense and investment than originally planned.

As the need for renewable energy and sustainable practices increases every year, so does the need for more efficient and effective maintenance strategies of these technologies. In the solar industry, the solar panels are required to be free from dust, debris and other pollutants that could affect the performance and overall efficiency of the panels to generate electricity. This has led NrG to explore and pilot a nano-coating technology on a solar plant, with the aim to protect the solar panels without impacting their effectiveness and reducing the maintenance required.

1.     Hydrophobic

The research led us to understand more about the many advantageous properties that nano-coatings can display, such as being hydro- and oleo-phobic as well as hydrophilic. This means that the coating repels water and oils and provides an anti-stick surface. This is beneficial as it allows for the solar panels to dry quicker and guarantees that less water is needed to clean and maintain the panels. In addition, this characteristic ensures that the panels remain cleaner for longer as the liquid droplets will carry away pollutants, this is often referred to as the self-cleaning property[1]. An example of the hydrophobic water droplets can be seen in Figure 1 below.

Figure 1: An example of hydrophobic properties[2]

2.     Anti-reflective

Furthermore, nano-coatings can have anti-reflective features, meaning that they are more effective in absorbing light[3]. This is useful as it reduces the reflection of light and enables better solar panel efficiency in low-lighting conditions. Thus, allowing for more energy generation during early mornings and late evenings.

3.     Repel Micro-organisms

The growth of micro-organisms such as moss, mould, and lichen can also be avoided through nano-coatings[4], which can prove favourable in places where there is high humidity and rainfall, further protecting the solar panels from extra damage. An example of moss growth can be seen in Figure 2 below.

Figure 2: Example of moss growth on a solar panel[5]

4.     Physical protection

Not only can nano-coatings exhibit all these properties, but it also acts as an extra physical layer of protection from etching, scratches, and surface degradation[6]. This is beneficial in extending the useful life of the solar panels and ensuring less damage from the external environment.

5.     Improved efficiencies and O&M cost

Studies have also shown that nano-coatings have helped to improve solar panel effectiveness and overall output power generation[7]. In addition, they have shown to decrease maintenance costs and reduce cleaning cycles[8].

6.     Pilot Project

In April this year, NrG undertook a nano-coating pilot project at a customer’s site using 200 solar panels, where 100 panels were coated with a nanomaterial. The remaining 100 panels were left uncoated as a baseline to evaluate against. NrG’s goal was to investigate whether these above-mentioned beneficial properties of the nano-coating technology can be utilised to have longer-lasting and more efficient solar plants. This pilot project will run for a year, after which NrG can justify the impact and performance of nano-coating and give recommendations for future solar sites. Figure 3 below, shows NrG’s freshly coated panels in a late afternoon sun.

Figure 3: NrG’s freshly coated panels in a late afternoon sun

[1] https://solartechadvisor.com/solar-panel-nano-coatings/


[3] https://www.coating.com.au/solar-panel-coating-australia/

[4] http://blog.thesolarlabs.com/2020/11/05/nanotechnology-in-solar-energy/

[5] https://mossrooftreatment.com.au/roof-cleaning/solar-panels

[6] https://www.milkthesun.com/en/services/nanocoating

[7]Aljdaeh, E. et al., 2021. Performance Enhancement of Self-Cleaning Hydrophobic Nanocoated Photovoltaic Panels in a Dusty Environment. Energies, 14(20)

[8] Yadav, V. & Mishra, A., 2013. Role of Nanocoating in Maintaining Solar PV Efficiency: An Overview. International Journal of Applied Science and Technology, pp. 21-28.

Digital economy technologies have undoubtedly altered the way people live their lives and operate their businesses. It has made businesses more efficient, from digital records and the resultant reduction in paper consumption, all the way to systems automation and Artificial Intelligence driving efficiency. 

Remote working has resulted in a downward shift in commercial electricity consumption, a reduction in commercial real estate, and less work-related travel. This bodes well for industry’s carbon emissions, and this shift has been facilitated almost exclusively by digital technologies.

Big tech, big power

Despite these hugely positive impacts, the complex systems that empower digitisation are not without environmental impact. Big tech is a notorious consumer of energy, owing to the large amounts of energy required to keep their servers cool. Tech firms invest significantly in efficient cooling technologies in order to keep these energy demands lower, but these remain considerable. 

In fact, according to the International Energy Agency, data centres alone account for 1.5% of global energy consumption, and 0.3% of global carbon emissions across the supply chain. Hearing that the Bitcoin Network demands more energy than the entire population of Finland, really brings these energy demands into perspective. 
As our reliance on digital technologies and cloud computing skyrockets, and Cryptomining surges, these statistics are almost guaranteed to increase.

Africa’s “Silicon Valley”

Despite falling behind in our digital transformation potential, South Africa is nonetheless poised to grow into Africa’s tech hub. Amazon’s recent announcement to establish a headquarters in Cape Town, has really catapulted this notion. Currently, Cape Town boasts 550 tech startups, employing over 40 000 people. R1.2 billion of Foreign Direct Investment has been earmarked for injection into the industry, the city is well on its way to becoming Africa’s “Silicon Valley”. 

South Africa’s population of connected individuals is growing quickly, and sub-Saharan Africa is the most rapidly growing region in the world in terms of “unique mobile subscribers”. The region has a large population of young, connected, digitally savvy consumers. So, unsurprisingly Africa has received keen interest from a number of Big Tech multinationals, as well as significant investment into digital technology infrastructure development. 

Given South Africa’s unreliable electricity situation, investment into the digital economy should also be coupled with innovative energy solutions if we are to leverage this opportunity effectively. NrG has

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This month we share NrG’s perspective on managing beer quality throughout COVID-19.  This slide pack was collated based on insights gained from the ASBC webinar where various important aspects of beer quality management were discussed.  The aim is to provide brewers, plant managers and quality teams with some guidance to managing impact on production due to COVID-19. We are here to assist in the reliable delivery of quality beer to customers.