How solar plants should keep an eye on glint and glare
With more solar farms likely to be constructed near towns and settlements, developers will have to carefully consider the impact of glint and glare from photovoltaic (PV) panels before they proceed.
Global experience shows that sunlight reflecting off solar panels can cause annoying visual discomfort and even hazardous glare to surrounding receptors such as residents, motorists or pilots. Sunlight reflecting off solar panels can be experienced in two forms: glint which is a momentary flash of bright light; and glare – a continuous source of bright light. Both glint and glare can result in an after-image, which is a visual illusion where an image persists after exposure to the original image has ceased.
Motorists passing by may be affected, for instance, posing a potential traffic hazard – while nearby communities could be disturbed by sunlight reflections. Recent changes to the licensing regulations for Independent Power Producers have opened the door for private renewable energy projects up to 100MW. While most commercial solar projects to date have been located in remote areas, these developments may now be increasingly located closer to urban areas, according to Chris Dalgliesh, partner and principal consultant at SRK Consulting.
“We have seen a few solar projects being established fairly close to towns, and there will be more of these to come,” says Dalgliesh. “This increases the likelihood of glint and glare impacting more often on human settlements and other receptors.”
Sue Reuther, partner and principal consultant at SRK Consulting, highlights that while there was generally a high level of public support for renewable energy projects, the growth of solar farms had shown that glint and glare could be significant visual impacts. As such, these aspects have become an essential component of Visual Impact Assessments (VIAs) that SRK Consulting conducts for Environmental Impact Assessments (EIAs).
Kelly Armstrong, environmental consultant at SRK Consulting and a specialist in modelling visual impacts, says that developers need accurate, science-based predictions on how their solar installations might affect the local environment.
“A range of parameters are loaded into glint and glare modelling software to assess whether the glint or glare from solar panels will impair vision or cause discomfort,” says Armstrong. “This includes the project’s precise location, local topography and the height of the mounted panels – as well as the axes and aspect of PV arrays.”
The exact longitude and latitude determine the position of the sun across the seasons, allowing the model to account for the aspect of the sun on each day of the year. This is significant in measuring not just the occurrence of glint or glare, but to quantify exposure (minutes per day) to this impact.
Photovoltaic panels in a solar energy installation can be fixed or can rotate on a single- or double-axis, she notes. The model requires specific parameters of the proposed PV array inter alia the panels’ maximum tracking angle, resting angle and whether backtracking technology is used.
The position of the receptors relative to the solar energy installation is also critical. Typical receptors could include buildings, homes, roads and flight paths, with dozens of different points around the project all having to be assessed to understand the potential impact. Topography is important, as elevated areas around a solar farm could be more exposed to glint and glare. Dalgliesh notes that a viewshed is typically a vital component of visual impact assessments, and shows those areas (receptors) from which the solar farm would be visible.
“This spatial map guides our understanding of who or what will be visually affected by a development,” he said. “We can then identify those receptors which are likely to be most sensitive to visual impacts – including glint and glare.”
The outcome of the modelling, explains Armstrong, is to accurately predict the exposure and duration of glint and glare impacts down to the minute each day – for each key receptor.
“The accuracy of these models allows us to report very detailed glare results,” she says. “For example, we can predict that a particular receptor would experience glare for a maximum of 15 minutes between 4.30 and 6.30 pm during the summer months.”
This provides the basis for strategic decisions, either on the precise location or orientation of the solar farm, or on appropriate mitigation measures. While there are currently no legally specified thresholds for glint and glare, she pointed out that there are international best practice guidelines to follow.
“These guidelines incorporate tolerable exposure thresholds, viz. maximum 60 minutes per day, for more than three months of the year, above which mitigation measures must be implemented” she explains. “Our reports include mitigation measures, aiming to avoid any glare affecting receptors.”
Reuther highlighted that, as a leader in the field of EIAs, SRK is among only a few consultancies with advanced in-house expertise in glint and glare modelling – a niche likely to be in growing demand.View more
Solar PV and the value of your home
We offer a new perspective on the potential long-term value you can create by installing a solar PV system in your home.
Authors: Matthew Capes, Sean Moolman
To provide context we elaborate on why the reliability, affordability, and sustainability of solar PV make it a viable and valuable addition to your home. The trends in the South African residential property market and the current challenges caused by Eskom’s service are also discussed. We then move on to the focal points of Saleability and sales premium. To get insight into how solar PV systems can improve the saleability of South African homes, we spoke to two local residential property experts: Sandra Gordon, Senior Research Analyst, Pam Golding Properties, and Anthony Stroebel, Head of Business Development, Pam Golding Properties and Director of the Green Building Council of South Africa.
We conclude with a method designed to help you calculate an estimate of the potential home sales premium unlocked by installing a solar PV system in your home.
Read time: 4 minutes
The Context: Declining Grid Reliability and Increasing Cost
The transition to clean energy is critical to securing a sustainable future for humanity.
In an ideal world, this would be at the top of everyone’s to-do list, but each day brings its own challenges.
Especially in sunny South Africa.
Note: EAF = Energy Availability Factor
For example: How do I manage to keep up with rising electricity and water bills? How do I cook dinner, have a hot shower, or watch some TV with my family, when persistent load-shedding and unexpected blackouts leave us in the dark?
Solar PV has become an increasingly affordable, reliable, and sustainable solution to these issues.
*Annexure A includes more detailed information and references for the above illustration*
As a South African you are certainly aware of the challenges Eskom brings, and you may already be familiar with the reliability, affordability and sustainability provided by solar PV.
There are solutions to the current challenges faced by many South Africans.
But what about the future?
An important reality often overlooked, is that the solar PV system becomes part of your home once it is installed (solar PV panels are routinely guaranteed at 25 years or more).
This begs the question: can a solar PV system add future sales value to your home?
International research suggests that it can, however, we sought insights closer to home. A lekker local perspective if you will. We spoke with Sandra Gordon (Senior Research Analyst at Pam Golding Properties) and Anthony Stroebel (Director at GBCSA, Head of Business Development at Pam Golding Properties) about two forms of value:
Saleability is the extent to which the home can be easily sold or rented.
Sales premium is the ability to command a higher sale or rental price.
At the end of this article, we provide a guideline for estimating your own home sales premium.
Let’s begin with saleability.
Gordon and Stroebel note, “Saleability is always relative to that particular moment in time i.e what else is on the market that would be competing for the same buyers. Certainly, at this point in time, when solar PV has not necessarily reached any degree of critical mass, it is likely that solar homes will be competing with non-solar homes and will definitely, therefore, have a ‘value edge’.”
Let us elaborate on what that “value edge” is.
Independence from Eskom
Stroebel and Gordon anticipate that despite the lack of local research on the matter, the fact that South African electricity tariffs are rising steadily and load-shedding is set to continue for the foreseeable future, it is extremely likely that any measures which reduce utility costs and increase a home’s independence from state utilities would increase its saleability.
They explain: “With a large, young population – and with utilities becoming more erratic and expensive – new mixed-use developments typically include energy and water efficiency features, solar power and – in some cases – rain harvesting, etc. These features are undoubtedly attractive to the majority of potential homebuyers and, based on international trends, will be particularly important to younger buyers (who are an important source of housing demand in South Africa).”
Securing the value of your home means you should consider who the buyers are likely to be and what would attract them to your home.
Millennials in the Market
Research conducted by COGNITION Smart Data found that Millennial home buyers have “a strong ethic of sustainability” and are looking for “smart homes that are sustainable, efficient and healthy”.
Adds Stroebel, “Millennials want homes with the latest and greatest – and most environmentally compatible – technology.
“According to this research, millennials have a high level of interest in solar technologies to reduce their carbon footprint, reduce their energy bills and increase self-sufficiency. Trends which rising local tariffs and increased instability in delivery are likely to reinforce.”
So, they are young and they want to save the planet… and money too.
Environmental and Financial Sustainability
According to research conducted by CoreLogic, “Surveys have demonstrated that millennials tend to be more environmentally conscious, so it is no surprise that they are the ones driving the green revolution in housing.
Solar panels will continue to be more popular on single-family homes, each unit with its own battery and power management system”.1
Green features such as a solar PV system also provide financial sustainability in the form of direct savings on energy costs, improving the saleability of your home and a potential home sales premium.
In a 2018 survey by the Pam Golding Property group, “70.3% of its agents estimated that homes with green features record a price premium of up to 5%, while 54.4% of agents stated that buyers are showing an increased interest in green features.” 2
According to Ooba, “Energy-efficiency has become a buzzword for house-hunters – not just because of load shedding, with homeowners around the globe trying to go green. A home that is less dependent on the grid makes for a sound investment opportunity.” 3
What does this all mean?
A smarter and more sustainable home can offer you cost savings and certainty through independence from Eskom – and these solutions will undoubtedly make your home more attractive to prospective buyers.
All these factors (and more) combine to create a perception of the value in prospective home buyers’ minds.
As they say in marketing, perception is reality.
So, does this perception of enhanced value translate into real value?
Listed in Table 1 (below) are several estimates from reputable international research for quantifying the potential home sales premium as a result of having a solar PV system installed.
Table 1: Sources of international research on solar PV and home sales premium
|The Appraisal Journal cited researchers Ruth Johnson and David Kaserman||“Value increase of about $20 for every $1 saved on annual energy costs.”|
|A study by the Lawrence Berkeley National Laboratory||“$5,000 resale value increase for every kilowatt (kW) of solar installed.”|
|The National Bureau of Economic Research (NBER)||“Price premium of up to 4% (depending on size and age/condition of system).”|
Reference – 4
Using the methods in Table 1, we created a rough guideline on how to estimate your home’s potential sales premium by having a solar PV system installed. *Please see Annexure B*
The estimates from the National Bureau of Economic Research (4%) in Table 1 and the aforementioned Pam Golding Properties survey (5%) are close enough to provide a basis for estimating the potential home sales premium in South Africa.
In the following illustration, we depict a range of potential sales premiums made possible by installing a solar PV system in a South African home.
Acknowledging the limitations of applying these methods and estimates is pertinent, especially considering the lack of local data.
With that being said, we want to leave you with a final thought. Put yourself in the prospective buyer’s shoes. Imagine you have narrowed your choices down to two houses on the same street. The selling price is similar and so are the houses. The only major difference is that the owner of one house decided to install a solar PV system.
The houses don’t seem so similar anymore. One of them is smarter, more sustainable, and offers independence from ever-increasing electricity tariffs and protection against load-shedding.
Which house would you be more interested in buying or be willing to pay a premium for?
*We would like to extend a special thank you to Sandra Gordon and Anthony Stroebel. We greatly appreciate your time and effort spent on providing us with invaluable insights.
We know that solar PV can offer independence from Eskom’s unreliable service.
Although we were in lockdown most of the year, South Africa still experienced its worst year ever of load-shedding in 2020with a total of 1798GWh shed and 859 hours of outages.
To put that into perspective, there are 8 760 hours in a year.
Eskom has not been off to a good start in 2021 either. According to data from Eskom se Push we had already seen 560 hours of load-shedding in the first half of 2021.5
Will the situation improve?
According to a technical report by the CSIR, Eskom’s coal fleet’s Energy Availability Factor (EAF) has declined from 94% in 2002 to 57% in 2019. Degrading infrastructure, scheduled maintenance, and unexpected breakdowns exacerbate the rate at which the coal fleet’s EAF declines.
This means the situation is likely to get worse (at least, before it gets better).6
Solar PV has also become much more affordable, whereas Eskom is progressively more unaffordable. From 2007 to 2019, Eskom’s average electricity tariffs increased by 446%. Over that same time period, the price of solar PV modules decreased by more than 90% from R57,4/Wp to R5,32/Wp. 7
For the 2021/2022 year, the average monthly electricity bill is about R1 508 across all income groups in the four major metropolitan areas (Cape Town, Joburg, City of Tshwane and eThekwini).*B
Solar PV is dramatically more environmentally friendly too.
Several lifecycle greenhouse gas (GHG) emissions studies show that solar PV, at only 50g of CO2-eq./kWh, has a fraction of the lifecycle GHG emissions of coal (948g of CO2-eq./kWh). 8
Remember, most of the electricity generated by Eskom comes from coal-fired power plants.
These studies analysed the emissions over the entire lifecycle of each technology, from the mining of raw materials to manufacturing to operation to decommissioning at the end of its useful life.9
*We adjusted the monthly electricity cost and solar PV system cost estimates from the methods in Table 1 to reflect those in South Africa rather than America.
Using the methods from Table 1, we begin our calculation with R2 034, the average monthly electricity bill for lower-middle to upper-income groups (LSMs 5 to 10) for the 2021/2022 year.*B
According to the Appraisal Journal, a solar PV system can enable a home sales premium of up to R20 for every R1 saved on annual energy costs.
To calculate potential annual savings, we multiply the R2 034 average monthly electricity bill by 12 months, which equals about R24 000.
Next, we multiply R24 000 by R20 which gives us a potential sales premium of R480 000.
To get to that same R480 000 but using the Lawrence Berkeley National Laboratory method which estimates R75 000 sales premium for every kW of solar installed – you would need to have about a 7kW solar PV system installed. *C and D
According to a 2021 BusinessTech article, having a 5kW solar PV system installed will cost about R110 000.
This equates to R22 000 per kW installed, thus we can expect the 7kW system mentioned above to cost about R150 000.10
If our potential sales premium is about R480 000 and the cost of our solar PV system is about R150 000, we arrive at an arbitrage opportunity of R330 000.
We must consider that, if the potential 4% sales premium is R480 000, the total starting price of our home would need to be R12 000 000.
Since most of us don’t have a home valued at R12 million, let us work out the sales premium using the average selling price of houses in South Africa for property in the lower-middle (R638 200) income group to luxury value property (R2 300 000).11
In 2019, the average selling price of houses for the above groups was about R1 300 000. Subsequently, the 4% sales premium would be about R52 000.
Green Economy Journal Issue 48
Methods and Assumptions
*A – We want to make it clear: The ranges shown in the “Real Value: An Overview of Estimates” illustration, as well as the more detailed sales premium estimation guideline found in Annexure B, are based on rough international data which we further adjusted to make it more relevant in the South African context.
With many variables, some of which have changed drastically over the last few years, these sales premium ranges and estimation guidelines are rough at best. They are only intended to give a basic idea of how a solar PV system can potentially lead to a home sales premium.
*B – Average residential electricity consumption data was obtained from Goliger, A. and Cassim, A. (14 and 15 July 2017). Tipping Points: The Impacts of Rising Electricity Tariffs on Households and Household Electricity Demand. 3rd Annual Competition and Economic Regulation (ACER) 2017 Conference, Dar es Salaam, Tanzania. Last accessed: 21/08/2017.
*B – Average effective residential 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 electricity consumption values for LSM5-10 obtained from the above references.
*C – The solar PV systems as discussed in this article include battery back-up and are thus either hybrid or off-grid residential solar PV systems. Grid-tied systems do have some form of backup (AC grid power) and provide cost savings with solar energy they do not have a back-up in the case of load-shedding. Thus, in our estimations, we focused on hybrid and off-grid solar PV systems.
*D – At the time of writing the exchange rate was R15 to the DollarView more
Wake up. The sun is shining
OPINION PIECE | Wido Schabel, Chairperson of SAPVIA
In 1992, the phrase, “It’s the economy, stupid” was painted by James Carville, Bill Clinton’s political strategist, on the walls of the presidential campaign office. With South Africa facing the most challenging economic climate for generations, we need now more than ever to come together and plaster that slogan everywhere to remind every single individual what is at stake if we fail to act.
If you think I am being dramatic, then you have not been listening or looking around you, because right now we as individuals, citizens, and elected representatives risk missing out on a route to economic upliftment for all citizens. The time for self-reflection, slow and steady, incremental changes, and initiatives is over.
We have gone too slow for too long.
We have wasted valuable time not addressing one of the building blocks of our economy and our individual prosperity, looking for piecemeal solutions, patching a system that is not fit for purpose and hampering our businesses and lifestyles with the constant strain of load-shedding.
Enough is enough.
Today, South Africa is facing a crisis on three fronts. We face an energy crisis, an economic crisis, and an unemployment crisis.
One of these alone would be a hurdle for the government to overcome, but together they present us with unprecedented challenges that will require a concerted effort, innovative thinking, and speed.
And the answer, my friends, is literally staring us in the face.
We have everything we need to not only work our way out of the recession that is coming but to actually improve the situation for every individual and elevate our standing internationally as well.
As a priority, we must increase energy capacity and diversify our energy forms. We urgently need to move away from our dependence on finite fossil fuels. That is not a question, but how we do so and how we alleviate the impact of the decommissioning of coal mines is up for discussion.
The question on everyone’s lips is where the jobs come from to replace the value chain created by the coal sector. We must ensure that the transition is just and that no one gets left behind, and in this renewable energy represents not only a sustainable source, it also creates jobs right across the value chain.
Take for example Solar PV. With some 11GW of coal to be decommissioned by 2030, renewable energy can step into the breach. Not only will the 16GW wind, 6GW solar PV utility, and 6GW distributed generation more than compensate for the loss of coal, but will also create the much-needed increase in capacity we need to enable a functioning economy.
More importantly, the jobs created by these energy sources are plentiful. SAPVIA has commissioned a jobs study which we anticipate will report that utility-scale solar PV projects can generate between 7-14 jobs per MW capacity, commercial projects between 10-12 jobs, while residential projects could create up to 14 jobs per MW.
These numbers are not to be sniffed at and we could use the current energy crisis as the impetus we need to make a step-change and address the fundamental flaws in our infrastructure and economy.
Not least because, as we seek foreign investment to support our under-performing economy our downgraded status, and the lack of functioning infrastructure in place, means that any promises of investment will surely come to nothing.
Why would any investor set up when they cannot rely on a stable electrical supply to enable their business to function? And for us here in South Africa, we are continually hampered by load-shedding that leaves us unable to operate and sustain our own businesses.
And as the economy shrinks our unemployment levels soar. The young are especially affected by joblessness with almost 50% unemployment, but across the board, we see too many people out of work and unable to lift themselves out of poverty and improve their circumstances.
As a result of the Covid-19 pandemic, unemployment levels will more than likely double, plunging us into an even deeper crisis.
So where do we go from here?
While it might sound like I am the harbinger of doom, I am not. I firmly believe that South Africa is on the cusp of seizing an unprecedented opportunity. We are sitting on the proverbial pot of gold at the end of the rainbow. A pot filled with natural, mineral and human resources.
I often say there is enough sun in Africa for us all, and when you add in our abundant wind, you can see that when it comes to natural resources our cup over-floweth. Harnessing these natural resources must be a priority if we are to emerge from the crisis.
But that’s not all we have right under our feet. Here in South Africa, we have access to the very mineral resources required to create and store the energy created from renewable sources. Platinum and Vanadium are the fundamentals required for battery energy storage systems and we have them in abundance.
Even better, we can actually become not just energy-independent but also an energy exporter, able to sell and improve our economic prosperity by shipping green energy abroad.
All of this would mean nothing if we didn’t have the people to set up the organisations to deliver the required renewable projects and maximise on the abundant resources we have available.
South Africa’s diverse population is filled with entrepreneurial, resourceful and multi-skilled individuals who are ready and waiting for the opportunity to drive forward our economy and put money into their own pockets and their families’.
So what’s holding us back?
We have a plan. The IRP has been out since October. But we’ve been on a go-slow for too long.
Players in the renewables industry stand ready to sprint ahead but are being held back by policy decisions and inertia that must be overcome if we are to emerge from this crisis with fewer people materially affected.
Some might ask where will the money for all this investment in infrastructure come from. We have so many options available to us. Local investors are chomping at the bit to play their part in driving the South African economy forward.
Unfortunately, South Africa is also one of the world’s worst CO2 polluters; fortunately, this means that there are global investment programmes that we can avail of to finance our transition away from a carbon reliant economy.
So again you might ask, what is holding us back?
Why are we missing this opportunity?
Because to me, it is a complete no-brainer for us to put the foot down and turn ideas into action.
Energy, energy, energy needs to be the focus.
Without a robust energy infrastructure, all will fail, from both a micro and macro perspective. We can only build the foundations of a prosperous economy if the building blocks are energy.
The SAPVIA jobs study has shown that the transition to a low carbon economy could create at a minimum of seven jobs per MW capacity. This is a conservative estimate and renewables has the potential to transform the jobs landscape with employment opportunities across the board, invigorating rural communities and offering access to new skills in localities where opportunity has been scarce.
We can and will address the re-skilling and up-skilling of individuals who are affected by the move away from coal and we can and will create an environment of proactive training and skills sharing that will ensure that every individual who wishes to participate in the new economy can do so.
Moving forward will require a concerted effort from government, industry and individuals. We need to all focus on the prize ahead, which will benefit every single individual across South Africa.
At its heart, this will be a just transition, where no one is left behind.
But it requires us to act now.
We cannot wait any longer.
- For information, visit www.sapvia.co.za