Lessons for new large-scale solar plant from open data

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GERMANY ENERGY SOLAR POWERAustralia is the sunniest country on the planet. ARENA’s recent large-scale solar competitive round has helped to drive down costs of capturing this abundant resource on a large scale, but existing solar projects – namely the two plants developed by AGL at Nyngan and Broken Hill – are feeding into the growth of the industry with the release of fascinating data sets that provide real insights into the unique conditions experienced by big solar in the Australian landscape.

Below, a glance into what this data means for new big solar plants in Australia:


The chart above shows total generation at the Nyngan and Broken Hill plants. Unsurprisingly, seasonality plays a big part in the output of the two solar farms. Generation in the warmer months peak at around 35 gigawatt hours – enough to power around 65,000 households over that month.

In the midst of winter, total generation is 17 gigawatt hours – still a substantial amount. Expected periods of low output can inform developers and operators of when to schedule maintenance, cleaning and necessary downtime.

Forecast uncertainty

The data also reveals that solar output can vary greatly throughout the day. The charts below show the maximum and minimum output , alongside the average for the time period:


Though the average is closer to the top of the range, suggesting the solar farms generate more often at the higher levels of their capacities, the lows and highs of solar output raise the importance of forecasting output, as clouds can have a big impact on this. And, even on cloudy days, the farms still generate electricity.

It’s also worth noting that ARENA is building capacity in the industry to deal with this variability by supporting research into solar forecasting).

The future of large-scale solar

A range of new technologies will impact the deployment and investment potential of large-scale solar in Australia – specifically, technologies that can shift the daily profile of solar output closer to the way we consume electricity.

AGL Energy included New South Wales demand in their data set. The chart below compares the daily output profile to daily demand:


Though our current system can safely and securely handle large penetrations of technologies like wind and solar, matching the two curves above more closely is increasingly valuable for the integration of clean energy in Australia (AGL Energy’s ‘virtual battery’ storage project, with funding from ARENA, is particularly exciting – a virtual system of 1,000 networked batteries that can store seven megawatt hours of energy).

Though we rightly boast of access to a rich solar resource, there are characteristics of our landscape, such as seasonal variation, the way households and businesses consume electricity and variations in weather, that play into how solar developers build big new solar farms.

ARENA’s knowledge sharing mandate, along with our efforts to decrease the costs of this new form of generation, are helping smooth the path for future large-scale solar construction in the sunniest place on Earth.

Source: ARENA. Reproduced with permission.  

  • Tim Forcey

    Nyngan and Broken Hill do not use single-axis tracking…

    …whereas some other solar farms do use (e.g. Moree), and will use (e.g. Mt Majura) single-axis tracking…

    …which improves capacity factor for solar farms.

    • solarguy

      I agree Tim. And storage also increases capacity factor further.

  • david_fta

    Data like this could be handy, it could be compared to minute-by-minute power consumption dta to tell us how many Nyngan solar farms we’d need to power Australia, and how much storage we’d need to time-shift supply to match demand.

    • Mark Roest

      That would be really valuable for getting investors to step forward for low-cost, high-performance, safe batteries.

    • Ian

      Another question to ask is how much demand can be shifted to match supply.

      • david_fta

        … how much demand can be shifted to match supply.

        It’s called “price”.

  • Gary Rowbottom

    All this is great, but there needs to be an effort put into large scale storage/despatchability. The virtual 1000 battery power station proposes 7 MWh of storage – Solar Reserve’s Aurora CST project for Port Augusta can provide up to 880 MWh of storage, per day – plus the benefits of rotating electrical inertia to the system. All that is needed is an SA Government PPA – the current SA Government energy tender will show how the government values renewables storage, and jobs.

    • solarguy

      Correct Gary, even though my training is in PV, I can’t ignore the very powerful CST technology, I’ve been a fan for years, it ticks all the boxes, but it needs to be built in places with very frequent and high solar insolation to be cost effective like Port Augusta.

  • Ian

    Amazingly good solar production profile , the resource ramps up quickly in the morning has close to capacity throughout the day and drops quickly as the solar resource fades in the evening, a very useful broad bell shaped curve. The daily demand curve for the state is interesting too. The amplitude of the variation is about a third of the average load. The biggest need is to analyse the load profile to see how it can be modified to fit the solar resource, after all this is precisely what was done in the past to flatten demand variation to suit an inflexible coal generation fleet. How much of the demand curve still reflects those demand modification efforts to match the generation profile of coal?