AEMO slashes output of five big solar farms by half due to voltage issues | RenewEconomy

AEMO slashes output of five big solar farms by half due to voltage issues

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In another blow to solar industry, five big solar farms in Victoria and NSW have output slashed in half after AEMO identifies system strength issues.

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Gannawarra solar farm in Victoria.
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The Australian Energy Market Operator has taken the dramatic move of slashing the allowable output from five solar farms in Victoria and NSW by half, because of issues over “system strength” that appear to have suddenly emerged.

The solar farms involved are Broken Hill in NSW, and the Karadoc, Wemen, Bannerton and Gannawarra solar farms in north west Victoria. The constraint limiting them to just half of their nominated capacity came into effect at 12pm on Friday, as this graph below illustrates.


Broken Hill slashed its output from 52MW to 26MW from that time (orange line in graph above from 12pm), Gannawarra (wiggly brown line) went from 50MW to 25MW, Karadoc (green) from 85MW to 42MW, Wemen (blue) from 82MW to 40MW, and Bannerton (pink) from 78MW to 39MW.

It is the latest in a series of blows to the solar industry, which has been afflicted by connection and commissioning delays, resulting in a blow out of costs and claims of damages to construction firms, as well as big changes to marginal loss factors, and the requirement for some to spend lots of money on synchronous condensers or other machinery.

To add to their woes, many solar farms in Queensland and South Australia have been forced to switch off during periods of negative pricing, either because they are required to do so under their off-take agreements, or because they are not willing to pay others to take their output over sustained periods.

Most of the solar farms affected by this latest ruling have been operating for some time – and in the case of the 53MW Broken Hill solar farm for four years. But it seems that the issue only emerged in a review just recently.

Some complained about the “blanket” approach to the constraints, but apparently it is difficult for AEMO to apply individual constraints in this instance. They wanted the issue resolved as soon as possible because of the potential revenue impacts. There is also concern about “contagion” into other regions.

The general market advice came in an oblique and typically coded market notice issued by AEMO just after 12pm. However, in a statement issued to stakeholders late Thursday, AEMO said it was working closely with a “number of solar farms” and network service providers to manage identified voltage fluctuations in north-west Victoria and NSW.

“Close analysis and management of this issue is required to ensure power system security across the associated parts of the Victorian and NSW 220kV electricity network,” it says.

“Until the fluctuations are resolved, AEMO will need to partially constrain the affected generators to manage power system security. AEMO has been working closely with all impacted generators, and anticipates an expedited remediation, reducing the impact and timeframe of required constraints.”

People involved say that the issue was raised in the last couple of weeks, and a solution is being worked on. But some expressed surprise the constraint was being imposed on solar installations that had been in operation for more than a year.

The blame has been levelled in roughly equal proportions (depending on who you speak to) at AEMO, at the solar farm developers, and at the antiquated market rules and regulations.

The latter is cited because, while new generators – be they wind, or solar – have to produce detailed modelling of the impact of their new asset on the wider grid, many are doing so in the dark because they do not have access to the full data required.

“The only way to solve this it is to have the whole network data available to the applications,” said one industry participant. “But the plant owners only get access to a theoretical model of the network, not a dynamic one”.

Others pointed to the general lack of planning and evolution from the energy industry’s policy makers and institutions, who have been caught with their guard down over the pace of technology, and have failed to make adequate planning for infrastructure (networks) and rules for the changes that have occurred.

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9 Comments
  1. George Darroch 7 months ago

    It’s not Abbott or Taylor who are damaging the renewables industry.

    • Francesco Nicoletti 7 months ago

      Well yes it is. If the government responsible for regulating an industry turns its back on it the industry is going to drift from one set of easily anticipated problems to the next.

  2. Cooma Doug 7 months ago

    Constraints have been around since the market began. I recall being constrained on at Murray Power Stations. We were pushed to 1200 MW
    at 10 dollars a MWHr. The constraint initiated by voltage problem on the other side of the SA grid.
    Being constrained on is often worse than being constrained off.

    This article is correct in suggesting the rules are not up to the task as yet. The complexities have grown and the solutions are available. But some time needed to establish.

    A wind farm or a solar system, if large and remote
    will be enabled via contractural arrangements with optimum located generators. The technogy needs adjustment and market rule support.
    But at the moment the potential assimilation of
    broadly located RE is far from optimum. The new rules and technology changes will not be the huge costs being visualized while standing in the old grid environment that still rules.

  3. Askgerbil Now 7 months ago

    Surplus renewable energy is to be expected. Planners in the renewable energy industry might only be thinking about their business model one week at a time. Options like producing hydrogen for profit from excess energy when the market for electricity can’t or won’t take more electricity have been explored in other countries.

    • Craig Fryer 7 months ago

      This is not a case of surplus RE. It is a case of the grid, the rules and the managers of the network failing to get it right. The solar farms were not given the information they needed. Only AEMO had that and they failed badly in this case.

      The turning off of solar farms in QLD was not due to excess supply or transmission problems. It was the QLD Government owned coal generators forcing the solar farms into a loss making price position. The QLD Government owned coal generators could afford to make losses during the day because the could make it up during the evening peaks.

  4. RobertO 7 months ago

    Hi All,

    I have just arrived and now they are giving me a shower. It just a lite one to keep the dust under control. I slowly move along and I get my hight graded so that I do not stand above the crowd.

    As I move (about 2 metres per hour). I have dried off and there is a gentle breeze blowing in the direction I am heading. I slowly warming up as I move further into the centre (I been here an hour or so but I am warmer than I was).
    Finally it happens (and there is a bigger breeze here too) and now I really am part of the crowd that I came to join and it has taken about nearly 2 hours, and it could take me another 4 hours to 6 hours to get to the final point where I depart from the crowd having been reduced in weight (I have lost 80 % to 95 % of my body weight. Some are still going but they have lost it as well.

    The area around me also starts to cool down but what left of me is still moving and some friends will travel back towards the centre but the general direction to away from the crowd doing their thing.

    What am I?

  5. Paulw 7 months ago

    I wonder how much of this has to do with the new 200MW Silverton Windfarm near Broken Hill. It is currently fully completed, undergoing testing and is only allowed to export at night.
    Add to that the Sunraysia and Limondale solar farms which are due to start testing as well and Kiamil due for completion at the end of this year. That’s an extra 900MW of power on a sunny windy day that they are trying to jam into a thin grid by Christmas.
    Kiamil’s synchronous condenser will hopefully help resolve this issue. Otherwise somebody needs to start building storage, or they might be waiting until the NSW-SA interconnector to be completed.

    • Alexander Hromas 7 months ago

      The synchronous condenser will do zilch to correct the problem as it can only correct power factor which solar farms can do in any case through their inverters. These units can help by generating volt amps reactive if the wind turbines run asynchronous generators i.e. they can correct the power factor at the wind farm terminals and improve ride through in the case of major grid disturbance.

  6. Aluap 7 months ago

    More incompetent governance, So what else is new. People used to be proud of a forward looking Australia but haven’t been for a number of years now.

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