AEMO points to rooftop solar’s critical role in “remarkable” heat event

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Queensland has nearly 2GW of rooftop solar installed across the state -– more capacity than any of its coal generators – and the value of that resource has been highlighted by an Australian Energy Market Operator assessment of a recent heatwave that hit the state.

We noted previously, in this story, how Queensland benefited from rooftop solar in the unprecedented heatwave, as coal generators faltered in the heat and the market operator had to turn to jet fuel to meet record demand.

The AEMO assessment, presented in its EnergyLive reports, highlights just how significantly rooftop solar reduced peak demand, and pushed it to later in the afternoon over the whole week of the heatwave.

Mike Davidson, AEMO’s head of operational forecasting, described the week-long heat wave as a “remarkable event”, and when state-wide average maximum temperatures averaged more than 40°C on two consecutive days.

“Prior to this event there had only been two days on record in February where the Queensland state-wide average maximum temperature had exceeded 40 °C – once in 1935 and once last year,” he said.

The impact of this was a week of records broken on peak demand.

“The previous record operational (or grid) demand for Queensland was 9,412MW set in January 2017,” he said.

“We saw this record literally being smashed every day during the ‘heat event’, and the new record now is 9,796MW.

“This is an increase of nearly 400MW, and to put that into perspective, is roughly the energy required to power a mid-sized town of 150,000 customers. If temperatures had reached what had originally been forecast, we would have seen even higher demand.

“The chart shows that (the) five days from 12 February to 16 February 2018 exceeded the previous operational demand record set last year. And when you add in roof-top solar generation to the operational demand, you can see that customer demand was even higher still.”

Indeed that rooftop solar clipped the peaks by up to 585MW on February 15, and more than 400MW on all the other days.

Imagine if it wasn’t there – and how much more jet fuel would have had to have been burned, and how much that would have cost.

Davidson says that growth in solar generation, from both rooftop PV and large grid-connected solar farms, is expected to be “quite phenomenal” over the next couple of years, in Queensland in particular.

“So the impact of weather is only going to become increasingly important in the years to come,” he said. At least in a heatwave, as NSW found to its considerable benefit in its heat wave last year, solar is a resource they can depend upon that won’t melt in the heat.  

  • john

    As householders install more and more solar the daytime demand will reflect the output from the systems.
    The early adopters put in small systems in some cases only 2 or 3 Kw.
    Now a 5 kW system is standard where the roof sizes allows.
    I feel all new housing will be at last be built East West so that the North South roof areas in the norther regions can be used for solar and below the Tropic of Capricorn the north area.
    The old method of build of houses from plans from America and Europe where heating the house was the main aspect will at last be discarded.
    Just look at those hideous black roof monstrosities, where the heat from the north side is on the bedroom and living areas.
    Not only that but those clown filled 600 mm roof eves, against what is needed at least 1.2 Meter eve to lessen the heat load.
    If everyone replace the lights with LED instead which use 1/48 of the power just imagine the saving in that area for one.

    • Joe

      Urban planning in new residential estates is a disaster. Homes with black rooves, surrounded by black bitumen roads and barely a blade of grass on the block of land, let alone plant some greenery for shade or soften the heat effect. I mean who allows this stuff to happen. No wonder the burghers living in the outer metropolitan suburbs need to go full throttle with the air con in summer. It should be made compulsory for every new home build to have rooftop solar installed to help power their air con units.

      • john

        Joe as a project, I so remember going and doing surveys on developers and the aspect of utilizing the land before laying out the blocks for best heat load and this was totally ignored it was all about getting the maximum number of blocks for the area they were developing.
        The answer to the question about heat load was; “Well they can use Air Conditioning”
        So you have houses with yes black roofs no flow through ventilation bedrooms on the north west corner.
        Why because of no inputs from Architects.

        • Joe

          Just dreadful isn’t it.

          • john

            Mate this has not changed in 40 years unfortunately.
            How many developers actually do study to understand the best way to lay out the development?
            I would submit none.
            How many builders do the same?
            I would submit none.

      • Andy Saunders

        I reckon a good part (underestimated) of the benefit of solar panels is the shading they provide to the roof below…

        • Rod

          Agreed, I noticed the difference when we installed our second array on the North meaning along with the first array and solar HWS most of the North roof was shaded.
          Solar salesmen should be pushing this bonus hard.

      • john

        Actually some new developments are doing as you say putting solar on roofs as a requirement.
        Mind not so long ago i remember a residential development where the building covenant was that solar could not be seen from the road way for peats sake!

        • solarguy

          Yep, That’s the biggest joke. There is a development not far from where I live that has that covenant.

      • Ian

        A major part of the problems with typical estate homes is the excessively complex roof shapes….. which seriosly curtail the potential PV capacity.

        • Brian Tehan

          The shape of the two storey houses with the top storey set back makes it very difficult to insulate the lower storey roof where it meets the top storey wall. You have a 60 degree ceiling space up against, up to a metre of the top storey wall.
          Most new houses are nowhere near 6 stars as built.

          • solarguy

            Another problem with two storey homes in regard to air conditioning is that cold air sinks down the stair well, making it inefficient!

        • Joe

          …just makes it all worse again.

        • solarguy

          Yes, very frustrating

  • trackdaze

    A couple of large scale single axis tracking solar farms west of the dividing range should broaden solars value in erroding the peaks of blue mountains (at least the fossil fuel powered part).

    Behind the meter batteries will plateu the mountain in total.

    • john

      May need to spread them from South to North to ensure the losses from transmission are mitigated but yes your on the money.
      Batteries definitely on the horizon.
      There is no reason I can think of as to why a large proportion of society could not meet 60 – 80% of their power needs with Solar and Storage.

      • solarguy

        Well no reason at all indeed. My hybrid system exceeds 96% of our needs p.a.

    • Tom

      I was just about to write that. Axis trackers would have been performing much better when the sun was low in the west, as opposed to most rooftop solar which is tilted north. This is right when the operational peaks were. It would have clipped the operational peaks even further.

      Not that there is anything wrong with rooftop solar.

      • john

        Tom to get a great handle on the difference kinds of outputs use PVWatts . Yes it is world wide and yes it uses 30 years of BOM data to make sure it is not optimistic. I do like their figures against for instance some of the Inverter Company figures as they are realistic.

  • john

    Monitoring the power output of a system i am looking at shows for any day recently 52% of power needs being met by the system.
    This is 52% of the 24 hours not just 07:00 to 17:00.
    Some days the system is using up to 190 Kilowatt hours of power.

    • Jon

      This is a commercial plant or factory?

      • john

        Commercial yes.

  • Jon

    It not only saved peak generation but peak distribution network load.

    It was distribution network failures rather than generation capacity that caused recent Vic blackouts, I wonder how much of a buffer we had up here from running into the same issues.

    The afternoon taper is what Victoria is trying to address with the afternoon bias feed in tarrif.

    • john

      Solution put in distributed RE all over the network be it Solar or Wind.

  • George Darroch

    One part of the load being not only lower but also later is that it gives the generators and distributors more time to prepare by firing up generation and curtailing use. Earlier peaks seem more likely to be mismanaged.

  • Andy Saunders

    The equivalent to 150,000 customers isn’t quite as dramatic as you might think – the natural population increase of Queensland is roughly 84,000 per year.

    • baseload renewables

      True, but a customer is a connection. Each connection will have 2.6 persons per household on average (2016 ABS); furthermore some of these customers will be businesses. So 84,000 people per year / 2.6 people per customer is about 32,000 extra customers per year.

  • Pixilico

    Here’s an interesting example of a “marriage made in heaven”:

  • Lynette Molyneaux

    Is the max demand (10219MW on the Thursday, for instance) gross or net? That is, does it include gross generation from rooftop solar or is it what was fed into the grid? If it was only what was fed into the grid, then our max demand for that week would have been considerably higher.

  • solarguy

    Giles, Surely you mean 15,000 customers?