Inside SA’s exploding solar energy industry

When the Integrated Resource Plan was drawn up in 2010, solar was limited to a few isolated panels on domestic rooftops, and until recently contributed nothing to the national power grid operated by the state-owned utility Eskom. But that is changing. By Hartmut Winkler.

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Until a few years ago, solar panels were a rare sight in South Africa, largely limited to the roofs of a few affluent households. This is changing rapidly, driven by three factors: the worldwide drive towards renewable energy, a highly strained local electricity supply, and a steady drop in solar panel prices.

Taking the lead from other countries, South Africa committed to an energy generation infrastructure development plan for 2010 to 2030, known as the Integrated Resource Plan.

Under the plan, the country aims to achieve 9,6GW of solar power capacity by 2030. When the plan was drawn up in 2010, solar was limited to a few isolated panels on domestic rooftops, and until recently contributed nothing to the national power grid operated by the state-owned utility Eskom.

But that is changing.

Solar plants are being developed, most by the private sector under a specially designed procurement programme. Eskom is also constructing some facilities.
In the past 10 years, the defining development in solar energy has been the sharp drop in the prices of photovoltaic panels. There have also been modest technological advances in other solar technologies and in power storage.

Photovoltaics, or PV, is a process in which energy from light is absorbed in materials and then directly transferred to electrons, resulting in an electric current.

Research advances over the years, especially those involving easily available silicon-based materials, have made this an increasingly cheap solar technology. It is also now the most popular.

The simplest PV configuration has immobile solar panels, slightly tilted relative to the ground and facing northwards towards the midday sun. An example is the Droogfontein plant near Kimberley in the Northern Cape. Panel rows are placed in a way to ensure that each panel does not shade the one behind it.

A more sophisticated design, found at the Sishen plant near Kathu, also in the Northern Cape, uses a single axis-tracking technology to counteract efficiency losses. Each row of panels rotates steadily along a north-south axis with the sun until it reaches a point where it starts to shade the row behind it.

In two-axis tracking systems, panels constantly face the sun squarely. The Herbert and Greefspan plants near Douglas in the Northern Cape use this technology. The cost of the additional tracking motors is compensated for by the capture of more sunlight.

Concentrated solar power
Concentrated solar power, or CSP, technologies are based on the redirecting of sunlight, normally by mirrors, to a common focal point, which as a result becomes extremely hot.

This heat is transferred by fluids to a nearby electricity generating unit, where water is boiled to drive a turbine. This is similar to the process in coal power stations where coal is burnt to generate heat.

CSP technologies include the solar tower, where a multitude of mirrors continually realign themselves to reflect sunlight to a hot spot on the tower. Khi Solar 1, under construction near Upington, is a representative of this class.

The KaXu plant is using parabolic trough technology

The KaXu plant is using parabolic trough technology

The parabolic trough technology requires long rows of concave mirrors focusing sunlight onto pipes running just above. The already operational KaXu near Pofadder uses this technology, and similar plants in Bokpoort and XiNa will be added soon. A related technology, linear Fresnel, appears in some of the proposals for future South African solar plants.

Finally, there is a hybrid technology, concentrated photovoltaics, where the collecting focal point contains a PV receiver rather than a heatable fluid. This design was used for the Touws River solar plant in the Western Cape.

Solar energy almost completely avoids emissions, uses a limitless energy resource and is becoming increasingly inexpensive. As such, it is promoted as a major clean contributor to solving the world’s energy crisis.

At the same time, it is important to recognise the shortcomings of solar power. Solar energy generation is only possible during daytime and in reasonably cloud-free conditions. In South Africa, that corresponds to typically eight hours per day on average.

For PV, the poorer the alignment between the sun and a solar panel, the worse the efficiency. Dust build-up on a panel further blocks sunlight, and photovoltaic panels don’t function properly if even only a fraction of the surface is shaded.

The quoted power produced by a panel or a solar plant is mostly obtained under near-optimal solar exposure. And the daily average power generated is much lower.

Energy storage also remains a challenge. Despite this, solar energy remains an attractive option.

All the completed solar power plants are part of South Africa’s electricity supply as they are fully linked to Eskom’s grid. Solar power already feeds more than 1GW onto the grid on a sunny day. This is a significant amount, and it makes it considerably less likely that the country will suffer power cuts in 2016.The Conversation

  • Hartmut Winkler is professor of physics at the University of Johannesburg
  • This article was originally published on The Conversation

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  • Davebee

    Pull the other one Prof it’s got bells on.
    PV solar is WILDLY expensive and as of Jan 2016 utterly beyond the financial means of the average working class (hopefully employed) family to effectively install even to power up the equally costly LED lights and a couple of lap tops.
    Call me when the local solar crew in the private sector have dropped the local raw production/installation price to 50% below today’s astronomical costing within the space of 6 months. As we start down the road to the global Great Depression v2.0 that is simply never going to happen. Sadly, Eskom will be screwing us for many a year to come!
    Need an alternative power source? Try gas, it’s practical and reliable as well.

  • Chris

    But why is it so difficult to go to a bank and get a loan for solar and instead of paying Eskom my R4500 per month, I rather repay my R4500 back to the bank and after 5 years the loan is repaid, and I can actually score out of this deal.

  • Chris

    The solar guy didn’t even want to give me a quote for my place with the current usage. He said it would be close to a million with my current consumption with 2 houses and 2 cottages. I’m now in the process of replacing lights with LED lights, (even a 3 watt globe is more than enough to light a room!) and then the next is the gas stoves and gas geysers. Its going to take longer because getting a loan from the banks for all of this is a big pain in the ass even though I only have a current loan for half of what I bought it for and the place is worth double than what I paid for it. All I can do is to go slow and easy and hopefully then I do go over to solar totally there might have been some more improvements.

  • Davebee

    I bet you can’t wait for the Zumanauts to land their ‘special’ nuke deal with the Russki oligarchs Chris.
    A trillion here a trillion there, next thing Tina Whatseherface will talking real money hey?
    Oh, regarding that bank loan? Be very cautious, I’m with the property industry and the word out there is DANGER, interest rate rises in 2016.
    Thought I would share that cheering news with you.
    (I’m not going to be suspended for saying something perceived as having a racist undertone am I?)

  • Contact David Lipschitz on My Power Station on Facebook to give u way more informed advice and a consultation regarding changing to green energy. Remember that change also means changing how we live and making different lifestyle choices. For example, using our solar geyzer is about moving to bathing/showering at night and not mornings, etc etc. Go green, or no go home…

  • Homeowners in the City of Cape Town can make part of their electricity cheaper than they can buy it. And not just rich homeowners but poor and middle class ones as well.

    And in July 2015, many businesses reached “grid parity” where the cost of self generation is less than the cost of buying from Eskom or the City. These businesses who are spending R1,20 per kWh or more can save by installing photovoltaic systems. Hence the systems on Black River park offices and the recent 900 MW on the Waterfront roofs.

    Companies don’t do things, generally, unless they have a profit or cash flow advantage. In the case of electricity they have both advantages.

    It is still very difficult to export to the grid in Cape Town, because of red tape. So the installers with whom I work and I recommend that homeowners self generate half of their electricity needs and also put a battery bank in for days when there is load shedding.

    If government would pay us, we could remove ourselves from the grid at peak time, or make our peak demand the same as what our demand is the rest of the day.

  • Re: “For PV, the poorer the alignment between the sun and a solar panel, the worse the efficiency. Dust build-up on a panel further blocks sunlight, and photovoltaic panels don’t function properly if even only a fraction of the surface is shaded.”

    Regarding alignment: this is true, but as the cost of PV systems has dropped more and more it hardly matters. When the price was high we spent much more money on special roof top brackets and ground mounted trackers to make the panels face true north (in the Southern Hemisphere), or follow the sun during the day. But even in those days we still mounted some panels in an Easterly Direction to get the maximum effect of the rising sun to recharge batteries in off grid scenarios.

    Regarding shading: it depends on how the solar strings are set up. And if micro inverters are set up, then the losses are minimised. It also depends on the number of bypass diodes used in the panels.

    We clean the panels on our house about twice a year. Dust and bird droppings have hardly any effect on our panels.

    Cape Town has about 5.7 average sun hours on average during the year. Upington has about 8 sun hours. For quick calculations we use 5 average sun hours in Cape Town to get a better idea of what to expect. This is because of inefficiencies in the system, or because of really hot days in summer when module (panel) output drops.

  • Nice one thanks David! Anyone else want to join in and reply to David?

  • Chris

    Im most certainly fixing my rate for the next few years. (And if you white, you are racists, you just cant help it..)

  • Greg Mahlknecht

    >I’m now in the process of replacing lights with LED lights, (even a 3 watt globe is more than enough to light a room!)

    Best place to start. I have converted entirely to LED and the savings are significant. The best thing I did was buy one of those power meters with a clip on to the DB, so I can see what my home is consuming. By getting in to the habit of keeping an eye on it, you get an idea of what eats the power. I got decent timers for my pool pump and geysers, and generally over the years been far more mindful of doing a few minutes research on any appliance’s consumption/standby consumption before I buy. All the little bits really do add up.

    Small note – 3W isn’t nearly enough to light a room in my experience, unless it’s where you keep your prisoners under the staircase. I use 8W for outside lighting (replacing 100W incandescent or 20ish? Watt CFL) and 5-6W for replacing 50W downlighters.

    Tip – if you’re not afraid of tinkering, go to an electrical supply store and you can buy auto day/night sensor/switches and install them, then you can use cheaper LED bulbs in your outside lights, the auto day/night ones are expensive and not easy to find.

    Tip2 – buy brand name lights with 2-3+ year warantees, and keep a box with all your slips in them. Then write on the bulb base in permanent marker when you bought it, so you can match it up again – these things aren’t cheap, they do die sometimes, and it’s worthwhile getting replacements, unlike CFL/incandescent where it’s hardly worth the trouble for the cost.

    Tip3 – if you have 12V downlighters, when you replace the bulb, convert to 240V LED downlighters. I ran quite a few tests here, and 240V LED bulbs used between 20% and 50% less depending on the age of the transformer. It’s easy to do yourself – if you can put a plug on, you can remove the transformer and put in a 240V socket.

  • Chris

    Thanks for the hints and tips.
    I must say the first one I replaced was in the kitchen. The 5 watt just gave to much light. I actually moved the 5W to the outside, for the entrance of the house and a second 5W under the roof of the house for the cars,.
    I found that the 3 watt in the kitchen still give more than enough light. I would say its somewhere between a 60W and 100W globe, where as the 5W was most certainly like a 100W. It was just to bright and white.

  • William Stucke

    Our banking industry has happily patted itself on the back for being more prudent than others and not going down the drain in 2007 – 2008. The flip side of that is that they are actively retarding investment in the country. They haven’t the faintest idea how to deal with risk.
    Example from yonks ago: Madam wanted to open a nursery school. Business plan showed a 4 month payback on a modest investment. Bank Manager (yes, they still had them, then) said it looks great. She sent out the consultant. He was full of enthusiasm. Said no problem. Piece of cake. Came back a few weeks later and said sure, we’ll give you the loan, at ruinous rates. All I needed to do was hand over 220% of the loan value in shares.
    It simply didn’t seem to occur to them that I could have sold some of the shares and cut them totally out of the deal.

  • William Stucke

    > We clean the panels on our house about twice a year.

    My borehole pump is powered by two PV panels. It’s a poorly designed system (not by me – it is a demo system*) and unless the panels are cleaned every month – and after every veld fire – I have no water.

    * My installation and operation reports were so scathing about the poor design that the importer gave it up as a bad job! There should have been three panels. A classic example of not understanding the difference between open circuit voltage and operational conditions. Plus a bunch of other issues. But I have free water 😉

  • Chris

    They really don’t think at all. About 20 years ago, put in a business plan to buy a shop in the lowveld. It was for R220 000. Everything in order and all was set to go, but the bank took so long get everything going that the guy sold to a cash buyer. I could have been a rich shop owner today, that’s for sure!