The day rooftop solar met one third of South Australia's demand | RenewEconomy

The day rooftop solar met one third of South Australia’s demand

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South Australia sets a new record for rooftop solar, with more than 2/3 of daytime demand met by wind and solar.

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We’ve documented the growing impact of rooftop solar on the electricity market in South Australia on many occasions, but on Boxing Day just passed it may have hit a new record.

According to this graph from the Australian Photovoltaic Institute’s Solar Map, rooftop solar contributed up to one third of total demand in the state in the middle of the day, and at least 30 per cent from 11.30am to 3.30pm.

SA Bozing day solar

The South Australian grid operator has recognised the benefits of rooftop solar on the grid – it says it has pushed the peak back much later in the day, reduced the breadth of peak demand (much to the chagrin of the conventional generators who relied on the peaks for income), and reduced stress on the grid at peak times.

Indeed, this graph here shows over the three days around Boxing Day. It registers only grid demand, so not rooftop solar.  Notice the dips during the day – from the grid’s point of view, off-peak now comes in the middle of the day.

SA Pitty sherry

But here is what the total electricity demand looks like with solar included – courtesy of the APVI Solar Map data and some chart-work from energy analyst Hugh Saddler at Pitt&Sherry.

sa total power boxing

It shows that wind accounted for nearly half of total demand on December 26. Which means that wind and solar accounted for around two thirds of total demand for large parts of the daytime hours, and just over half over the 24-hour period.

Saddler notes that total electricity demand in SA on December 26 was low for summer because the day was relatively cool (maximum temperature in Adelaide 23.4 deg. C) and also a public holiday.

“That said, the data show that there is no technical impediment to renewable sources of generation supplying a high proportion of total electricity requirements,” Saddler says.

” The combined share of wind and solar for the whole day (midnight to midnight) was 52 per cent.  The data also show the benefits of technology diversity in renewable generation.  Wind and solar generation  complement  each other when, as is very often the case in SA, there is more wind overnight than during the day.

“This demonstrates that, when Australia eventually gets serious about transforming its electricity industry towards a low emission future, both technologies should be important parts of the total generation mix.”

And, Saddler adds, the data shows the economic benefits for electricity consumers of interconnections between states.  For most of the day low cost brown coal electricity imported from Victoria displaced higher cost local coal and gas generation in SA, but on a couple of occasions surplus generation from wind in SA flowed east, helping to keep prices in Victoria slightly lower than they would otherwise have been.

There are several things to note about South Australia. It has the highest penetration of rooftop solar in the country, with more than 23 per cent of all customers having solar. It also has nearly 50 per cent of all wind capacity in the country, at around 1,500MW.

And as a result of all that, one of its two major coal generators is mothballed, and the other operators only part of the time. And its biggest gas plant, the Torrens facility owned by AGL Energy, will close half its capacity too because it is no longer needed.

Indeed, on an annualised basis, the state now meets around 40 per cent of total demand through wind and solar. That is expected to jump significantly in coming years.

The state government has a 50 per cent target by 2025, but in reality it could go much higher than that – even to 100 per cent – particularly if the national renewable energy target remains in place.

The prevalence of variable wind and solar underlines the importance of energy storage going forward. But battery storage is already proving to be economic, particularly in the role of avoiding costly upgrades and extensions to the network of poles and wires.

This in turn will encourage more renewables. The SA grid operator itself suggests that the future may lie in a series of renewables based micro grids based – it sees little future for conventional generators, or even conventional electricity retailers.



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  1. tsport100 5 years ago

    Odd that the ROAM Fuel type ad on this page doesn’t even list solar in it’s key?

    • Paul McArdle 5 years ago

      Not “odd” (as the AEMO does not currently publish information about solar generation) but it is frustrating, for those who want to see the full picture.

  2. Henry WA 5 years ago

    In the second graph, I can understand the dip in Grid Demand in the middle of the day due to roof top solar. What I don’t understand is the apparent sharp but short lived peak in demand at midnight on each night shown from 24 December to 27 December. Is this to do with time of use pricing? If so, it is very badly designed.

  3. disqus_3PLIicDhUu 5 years ago

    Imagine if solar had been done properly with solar farms and solar power stations instead of banged in willy-nilly on roofs, we would have had a much higher yield, for much less cost, on the chart,
    Instead were stuck with the greatest of engineering follies and waste of good resources, in history, the domestic solar initiative.

    • juxx0r 5 years ago

      Y’know that people are doing it because it’s more efficient than buying from the grid. So wouldn’t you be able to say that the grid is now “greatest of engineering follies and waste of good resources, in history?”

      • disqus_3PLIicDhUu 5 years ago

        That doesn’t follow, the grid, like the original phone system connected all to a standard and a pool of easily accessible and cheap energy and granted times and technology changes.

        But ask yourself this-
        If a town installed 10,000 grid connected solar rooftop 3kW systems, in your average differing orientations, shading, equipment types, quality of install, maintenance and lack of, would this have been better than 10x 3MW solar farms connected to substations,
        With these attributes-
        Economies of scale.
        Maximised Orientation.
        Agumentation of Grid Parameters (even at night)
        Uniform equipment types
        Guaranteed Maintenance
        Likely easily upgradeable.

        So can you say an individualistic feel good factor, quasi- free market, “look I’m generating my own energy” was worth the massive difference in $/kW?
        A conservative government folly of individual ownership, into a socialist network, what a farce.

        • juxx0r 5 years ago

          Sure it follows. No concrete, no additional structure. More efficient. Only inefficiency is lack of purchasing power and more labour, but that’s not a bad thing. Also end of line power, lower transmission losses, lower conversion losses, lower distribution losses. other benefits include multiple orientations, dispersed production for clouds, and saving for the owners

          • disqus_3PLIicDhUu 5 years ago

            No it doesn’t follow at all, the transmission losses would be very low when located next to a major substation, besides the added bonus of augmentation of grid parameters.
            So you’re saying that the cost of solar farm structure ends up more expensive, in triple bottom line accounting, I would suggest, that it would cost more for the roof mounted, decentralised and mostly independently managed systems and inefficiencies in all areas, also what if the solar farm doubled as commercial sheds for the structure?
            How do multiple orientations give better output than true north orientation, all it does is shift some energy output for some generators around to better morning or evening output to create a maybe 5% worse yield for that generator.
            The fact the farm’s output is lower out of hours has no relation, due to the grid, unless the grid in the area, was reliant upon it.
            You totally missed the lack of maintenance on rooftop systems, inattention to cleaning, encroaching shading, faults etc etc Why? because your logic is flawed

    • Pedro 5 years ago

      Imagine if we had a government that encouraged utility scale PV, then it could be done “properly”. So in the current politically RE hostile environment we have a robust domestic scale solar industry. And even with the inefficiencies you list for the domestic market, PV still makes economic sense.

      When there is a change in government attitude towards RE then at least we have a base of skilled people to put in the utility scale RE projects.

      I think you are being a bit over the top with the “socialist network, what a farce comment”.

      • disqus_3PLIicDhUu 5 years ago

        Exactly the politics that instigated domestic solar was the conservative Howard government, bent on the free market and look at the short sighted mess that’s left, though from their viewpoint look how now we can create a massive maintenance repair and upgrade market.
        See how this beast feeds itself through the inefficiencies and waste; if your all good for wasting your tax dollars.

        • Pedro 5 years ago

          Totally agree with you on the $8000/kW subsidy and then the overly generous FIT system was way too generous and hugely distorted the market. It lead to a lot of very poor quality PV systems being installed.

          We now only have the STC up front discount system which I would much prefer that the end user can only claim, rather than the installer. Then at least the true system cost would be transparent to the end user and the customer can make a more informed choice on the quality of the system.

          As it presently stands there are no tax payer funded incentive schemes for new build PV.

        • Pedro 5 years ago

          Not sure how big the maintenance repair and upgrade market is. It is certainly smaller than the car repair market and would probably be a similar size to any domestic white good repair market. And so what if there is a repair and maintenance market, employment is a good thing. Taxes aren’t paying for it, in general it is the suppliers and manufacturers who bear the costs for items under warranty.

          I recently cleaned 3 months worth of dust off my panels and I was thoroughly surprised that the increase in output was barely noticeable. Perhaps an extra 1 kWhr on a 5.5kW system. Took me half an hour, that I may do twice/year, so provided your inverter lasts, maintenance is fairly low. I suspect that cleaning panels is probably a waste of water and time.

          • disqus_3PLIicDhUu 5 years ago

            The maintenance of domestic systems is left to chance in most cases, even though in contracts designed by the CEC, that you sign, the maintenance schedule is referred to.
            I’ve been to systems that were out of action for months, before their power bill informed them.
            Of course it’s smaller than the car service market, if that’s your answer why bother commenting and let’s create work where no needs be done, well done, as long as you don’t pay hey.
            Taxes did pay for your subsidy, that’s what I meant.

            If you clean your panels every 6 months you would be the rarest of system owners and yes you may gain 4-10%.
            That was not what I was referring to, what I meant was comparing OVERALL the domestic vs the commercial/industrial scale systems, that means if we considered 1000 domestic systems against 1 solar farm, not your own little personal case, but then again that’s the problem, thinking on a bigger scale than yourself.

          • Pedro 5 years ago

            Don’t get me wrong I agree that utility scale PV will always have a maximized output in minimized O & M cost when compared with distributed residential systems. And also arguably lower install costs.

            Where we differ is on our opinions. From what you post it appears that you believe domestic scale grid connect PV systems are a complete waste of resources and money. On that point I totally disagree. I would love there to be a robust utility scale PV market but in the absence of that, a strong domestic PV market is a close 2nd best option even with the inefficiencies that seem to really rile you. It also appears that you do not seem to acknowledge that both markets have advantages and disadvantages. Key advantages of the domestic market is there are no land costs, no power line costs, rapid install (months as opposed to years). In Australia the domestic market is about 500-700MW/year. Utility scale PV does not come anywhere near close that figure.

          • disqus_3PLIicDhUu 5 years ago

            I think there’s always a market for domestic PV, in the correct balance, where its inconvenient to have LSG solar, there’s also remote area off grid.
            Your right the politics has totally thrown out what would have been the best option, so this just adds to the facts of the waste of the industry.
            As I was saying, a solar farm does not need to be a waste of land it could be installed on commercial and industrial sheds.
            The grid hookup costs depend on the distance to grid, what if this was next to a substation.
            I could say the same for your domestic solar when it pumps back to the grid on a long lines, what are the cumulative losses on 1000 domestic pv systems, how many installations needed remedial work to allow for the domestic install, how many lines needed upgrades, due to impedance issues, etc, .theres a long list of issues.
            Domestic scale PV is not a good 2nd best option, it’s at best a poor 2nd or fair 3rd
            Efficiencies really rile me yes, that’s what the double edged sword of renewable engineering is all about, efficiency.
            it’s even in CEC guidelines to audit first.
            Efficiency and generation, audit for improved efficiency and then calculate generation requirement.
            Proper auditing using triple bottom line accounting at government level, would have picked up the massive inefficiencies of mass domestic pv, even risk analysis would knock it back.

          • Pedro 5 years ago

            The PV standards are pretty clear on line losses up to the meter box for domestic PV (max up to 6%). Line losses on the power lines is harder to quantify. A fair guess would be total losses of between 10-20%. However most domestic PV will not be approved or restrained by the utility if it is likely to cause voltage rise in the power line. It does commonly occur that inverters do shut down due to high AC voltage, again this is very hard to quantify unless the system is monitored. Some micro inverter manufactures may be able to answer this question.

            On another note by my calculation you would need about 7000m2/MW of PV. That is almost 1 ha/MW. You could quite easily have 50m cable runs from 1 string to the inverter. To keep to efficiency losses of under 5% starts to get expensive with cabling. I would assume that 2-3% DC cable losses would be acceptable for a utility scale system. By the time that power gets to the end user you could be easily at the 10% mark for line losses.

            By risk analysis do you mean people getting an electric shock from PV, or a DC wiring fault causing a house fire? So far I am not aware of any such incidents, but I am sure some must have happened. There was the poor quality rooftop DC isolator issue and I have seen burnt out ones but luckily did not result in a house fire or injury. With over 1 million domestic PV systems installed I would say the risk is very low.

            In an ideal world all business would use triple bottom line accounting. So why insist on it for the PV industry when the FF sector clearly only gives it PR lip service.

          • disqus_3PLIicDhUu 5 years ago

            The domestic pv when it comes to losses is all over the place and your loss figures sound a fair average.
            With the solar farm the dc is allowed to be at greater than the 600V maximum permissible for domestics, so if it was running at 1000V, your cable losses would effectively be halved, 50m farm = 25m domestic string..
            Most domestic systems are unmonitored by the client, resulting in unknown operation of systems and those that are, are left mainly to the untrained clients, to assess.
            Your land area is very fair in assessment, remember though this could be on large sheds, or combination sheds and land.
            The 1ha/MW is 100mx100m, relate this to 333x3kW domestic systems ideally situated, truth is we’d need probably another 20% more domestic, at least, to allow for the idiosyncratic issues about 400 individual systems.

            By risk I mean all levels of risk, persons, property and financial, it is much higher for rooftop systems.

            Triple bottom line goes hand in hand with sustainability and the environment, can’t say we are installing these systems under the auspices of environmental considerations and then throw the real reason for the initiative out the window, baby and bath water.

          • Pedro 5 years ago

            At least financial risk for small systems is low. That is, a $10K system even if it never works is very unlikely to lead to bankruptcy.

            My gut feeling is that very few people install PV for environmental reasons, just happens to be a feel good side benefit. It is all about reducing your electricity bill in the face of ever increasing electricity prices.

            Thanks for the conversation, it has been a good debate. I will see if I can find out how frequently the grid voltage and frequency is outside inverter operating parameters

          • disqus_3PLIicDhUu 5 years ago

            It wasnt particularly aimed at saving individual’s bills as much as enviromental concerns with that added benefit. But no worries it’s been an education.

    • coomadoug 5 years ago

      When the wholesale electricity market shifts to the load side of the meter, the value of home solar and batteries will double at least. The new technologies can then be utilised to their fullest. The value of selling power from prices set in the home is something with huge potential.
      We will have large scale solar and wind. But there will be a lot of small dispersed generation as well. The move toward high density living also makes large scale solar an economic option/necessity.
      Large scale will not bring with it as many technology advances as will small scale generation managed by the car computers with price signals based on need and technology optimizations.
      Recent studies are fairly convincing in the analysis that the population of the world will grow to 11 billion and sustain that number without increase. This does suggest that the ratio of high density to low density will shift but not to the extent some may argue. In that case the dispersed energy scenario is most likely the dominant line the industry will take and the economic signals would suggest this. Also the billion who are without electricity in the developing world will achieve a result without a grid. A grid however, will be needed to provide for the transport industry due to the realities of rapid charge options. Naturally we may have a number of home charging options and battery spare swapping

  4. Paul McArdle 5 years ago

    To add some context to the day, the AEMO tweeted about boxing day:

    “Lowest #sa #electricity demand since 1998 market start: 790MW at 1330hrs Boxing Day 2014. #AEMO Visit for more info”

    See here:

    Hence we had a situation where Native Demand (i.e. total consumption, including solar) is normally very low over the holiday period + then when we back a large solar contribution out (to get back to Scheduled Demand, which is what AEMO dispatches for) it comes to a low level indeed.

    If we get time, will provide a more at

  5. coomadoug 5 years ago

    In a building in NSW we cut the lighting bill by 70%. If you saw the numbers before it became an issue the cost of the old system would stun you. When we have 100kw of solar installed and the new management system, we will cut the energy use by 55%. When the wholesale market moves to the home use side of the meter, all our energy used will be purchased at the lowest price.

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