The day rooftop solar met two thirds of South Australia's total demand | RenewEconomy

The day rooftop solar met two thirds of South Australia’s total demand

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The change in South Australia’s grid continues to surprise energy experts, and is now accelerating towards its net 100 per cent renewable target.

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South Australia’s renewable energy transition continues to surprise energy experts, with the latest assessment produced by the Australian Energy Market Operator indicating that the push towards the government target of “net 100 per cent renewables” is accelerating rather than slowing down.

The latest South Australia Electricity Report published by AEMO on Thursday shows how far the state has come over the last 10 years: in 2018/19 the contribution of wind and solar combined to provide 52% of the state’s total generation.

The state, since closing its coal generators in 2016, has become a net exporter rather than an importer. Emissions have fallen to their lowest levels ever, the AEMO report points out.

And while the 2018/19 financial year did not paint a pretty picture on wholesale prices – thanks to some extraordinary events in the January heatwaves and the “contagion” from Victoria – prices in the last few months have been the lowest in the country.

South Australia’s share of “variable” renewables – wind and solar – is not the highest in the world for a substantial grid (Denmark beats it), but it is an achievement for a relatively isolated grid at the end of a long stringy line.

And in some areas, it is world leading. On November 10, rooftop solar accounted for an astonishing 64 per cent of the state’s “operational demand”, when the combined output from solar panels on homes and small businesses totalled 832MW at 2pm.

Rooftop solar has completely changed the dynamics of the local grid. It has shifted the time of minimum demand from the dead of night to the middle of the day, shoved the peak from the mid to late afternoon into the evening and after the sun has set, and created a clearly defined “duck curve” that is particularly visible in spring and winter.

“Rooftop PV contributed 50MW more at the underlying peak in 2018-19 than had been forecast the previous year, delivering 433MW at the time of peak, and keeping the time of peak grid demand to 7:30pm Adelaide time,” the report notes.

That means a lot less gas generation is needed at times, and what gas generation is required needs to be able to react quickly. That underlines the push for fast-start generators that will be rarely used, and will replace more conventional gas turbines as the level of battery storage increases, and other technology such as pumped hydro and synchronous condensers enter the system.

Solar PV contributed more than 10 per cent to local demand, but this could nearly treble over the coming decade depending on the ongoing uptake of rooftop solar.

And within four years, AEMO expects the output of rooftop solar to reach 100 per cent of operational demand, given that the accelerating uptake of the technology at both small-scale and at larger scale, where the installation on big industrial roofs and some ground mounted behind-the-meter installations is tracking at, or even above, its most optimistic forecasts.

To help balance this, South Australia is becoming a leader in the creation of “virtual power plants”, basically the aggregation – through smart controls and communication – of hundreds, or even thousands of rooftop solar and battery storage installations that can be deployed as though they were a single unit. That will also include electric vehicles.

These VPPs can be used just to inject power into the system, or provide system services such as frequency control. A trial conducted with Energy Locals and Tesla did just that earlier this month when it responded to a trip of the biggest coal unit in Queensland.

That particular VPP is likely to grow from 1,100 installations to 50,000 installation over the next decade, many of them on the roofs of low income and state housing, and will be supplemented by the state government’s own scheme to install 40,000 batteries, and other programs such as those run by Simply Energy and SA Power Networks.

The last financial year was notable for more significant events. The addition of the Lincoln Gap and Willogoleche wind farms took its installed capacity to more than 2.14GW. Its first three large-scale solar farms entered production, another big battery entered the market, and more large scale wind and solar and storage projects joined the queue for construction.

AEMO’s pipeline of new wind and solar and storage projects is more than 10.5GW. Some private analysis puts this much higher but AEMO has stricter criteria. If just one third of these proposals are built over the next 10 years, that will be enough to meet the state Liberal government’s “net 100 per cent” renewable target.

Any more, it will be able to fulfil its bigger aspirations of becoming a major exporter of renewable energy, either the electrons themselves via transmission links, or in the form of green hydrogen, or added value products such as “green metals.”

What does this mean for reliability? The outlook for the next 10 years, according to AEMO, is that there is no anticipated breach of the reliability standards – but it can never rule out what it calls a “tail risk event,” such as when a prolonged and vicious heat wave takes out multiple gas units. Nor can it rule out contagion from neighbouring states, such as Victoria.

Indeed, it suggests the South Australia could be affected should problems occur in Victoria and authorities decided to ‘spread” the hurt among energy users. That would make for some interesting political fallout.

But in South Australia, more batteries are entering the grid, the Tesla big battery at Hornsdale is getting a 50 per cent lift in capacity, and more fast start generation is being deployed, mostly to replace some of the current ageing and slow moving gas fleet.

The emergency “diesel” back ups are being leased to Nexif Energy and Infigen and will be converted to gas and deployed actively in the market. Infigen says this will enable it to build another 300MW of “firm” wind and solar power in the state.

Just to finish with some interesting graphs.

  • Figure 2 shows the estimated actual and forecast of annual rooftop PV generation for South Australia from 2010-11 to 2028-29.  The current uptake is already tracking well ahead of AEMO’s “central” scenario and a different category of larger scale rooftop PV (on industrial rooftops) is

    currently tracking to meet or exceed the “Step change” forecast.

This shows the emissions and emissions intensity from South Australia, which is clearly falling.

This is a useful graph to dispel one of the big myths, namely that South Australia is more reliant on imports from other states after the closure of its coal generators.

Actually, it’s not. It imports less from Victoria and exports more.

And finally, this is the average import/export flow on the main inter-connector to Victoria. From early morning to late at night, South Australia usually exports to its neighbour Victoria, the state heavily dependent on highly polluting brown coal generators.

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  1. GlennTamblyn 9 months ago

    Looking at the second graph, notice what happens to total demand around 11:30 PM. It spikes up then drops off through the night. How much of that is due to usage of off-peak tariffs and things like domestic hot water set to run on off-peak rates overnight.

    If the pattern shown is indicative enough of demand patters through the whole year, maybe it is time for SA to make the switch….. to having electricity tariffs that are at a minimum in the middle of the day!

    Switch all those current off-peak loads to run at midday, use more of the available solar and reduce the need for gas overnight. Modern approaches to DMR are great, but there is an immediate pool of old-fashioned DM available right now just by changing the tariff structure.

    • Rod 9 months ago

      Yes, it is mostly hot water systems coming on. Unfortunately we still have a lot of dumb meters which require manual intervention and/or a smart meter install

      This issue has been on the radar for years but no one is willing to pay for the upgrade. SAPN has a “solar sponge” distribution tariff coming in 2020 but I doubt it will do much.

    • Peter G 9 months ago

      Good point, that midnight demand peak made me laugh too.

      What is amazing is that this was discussed years ago even before Playford and Northern were shutdown – yet still little or no action. A few years heating hot water with gas generation could be put down to administrative incompetence/inertia, but this is now looking like vested interests at play.

  2. Seriously...? 9 months ago

    Can someone come up with a better term than ‘duck curve’?

    I mean, that’s a pretty strange duck. And only going to get stranger as things progress…

  3. Rod 9 months ago

    Today as part of the horsetrading to get a land tax bill up in SA, the Greens have managed to get solar and batteries on public housing.

    “SOLAR panels for 75 per cent of all existing and new
    suitable Housing Trust stock. Batteries will have to go on 75 per cent
    of new public homes.”

  4. JackD 9 months ago

    I hark back to my favourite soapbox subject – Increasing the interstate transmission capacity and route diversity!! Given that SA is mostly exporting to (i.e minimally importing from) adjacent states, the case to strengthen transmisson ties becomes more stronger.

    Balancing areas of surplus electrons with electron shortages elsewhere requires the ability to transport electrons.

    Some states and regions have higher generation prospectivity than others (likewise for Load areas) so load and generation share balancing is required.

    And of course transmission enables a certain level of time-shifting (e.g. more generation in western areas of the NEM in the late afternoon being able to supply loads located more easterly).

    When the 500% RE capability becomes looking like reality, transmission will be key. Talk won’t be about whether the 330kV Energy Connect link will be required to connect SA to NSW, it’ll be about building that plus other higher capacity links as well!!

    Transmission will also enable vast areas of Australia to be setup with myriads of Charging Points (at obsolete petrol stations).


  5. CU 9 months ago

    With addition of almost 500 MW roof top PC per annum, within 2 years it will be 100 % in the daytime many days.

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