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Batteries are sexy and synchronous, but will energy ministers trust them?

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If Australia’s electricity grid were to be the basis of a romantic novel, full of love, fear and temptation, then South Australia energy minister Tom Koutsantonis’s upcoming decision on battery storage would be one of the major plot lines.

Koutsantonis is currently juggling the merits of battery storage – sexy and synchronous to many – but largely un-known in large scale deployments, at least in these parts.

South Australia’s state government has been putting the finishing touches to its new $550 million energy plan designed to avoid future blackouts and reduce the ability of energy oligopolies to gouge on prices.

One of the most debated and contentious is the role of batteries in this future grid: Sure, it can do storage, and load shifting, but can it really do all the the other things (the 20-strong value stack) promised for a grid? And can it replace the ageing, dirty, increasingly unreliable and price-gouging gas generators that currently have prime position?

On Friday, during a Hydrogen Workshop at Adelaide Oval, Koutsantonis wanted to talk about using hydrogen’s benefits to create new industries, making use of SA’s upcoming abundance of clean low-cost solar and wind power.

However, all the questions from the floor were about other things, in particular about synchronicity and the role of batteries on a grid.

One person questioned the idea of trying to make the whole NEM synchronised to the same 50Hz, and that SA – at the end of the grid – should consider DC links. Koutsantonis replied by pointing out that, sadly, he didn’t own either the grid or generation in SA, so such decisions aren’t in his hands.

However, he said the idea has merit and talked about the success of the Texas grid in being independent of the rest of US, despite being in the middle of it (just like SA is in Australia).  He pointed to the similarities – a strong lead in wind energy and setting up the state to be the country leader in clean cheaper renewable electricity.

Then the questioning came to an area where Koutsantonis does has full control: on what role batteries can play on the grid, and what his team will allow them to do, especially in the areas of ancillary market services such as keeping a grid synchronous.

As we have read in RenewEconomy, the current thinking of his team may not allow batteries to play a role in anything much more than storing power for blackouts and when there are short-term power shortages, as AGL will be doing with its 1,000 battery virtual power plant being installed across Adelaide.

It was pointed out to Koutsantonis that many power grid engineers say that batteries – being as fast as they are, and all electronic and with the latest control algorithms – can provide synchronising and balancing services much better than massive lumps of metal spinning around with little control over them.

Koutsantonis’ replies were helpful and hopeful:

  1. He acknowledged that he himself has grown up thinking of batteries as akin to water tanks that one fills up and then empties and not much more than that.  So, all these new ancillary services provided by batteries is relatively new to him that he is still absorbing inputs continually from the industry and his team;
  2. He does have two clear goals for his Energy Plan he will not waver from: at least 50 per cent of SA power being locally sourced from state renewables, and at least 50 per cent of synchronous capacity also being local in SA;
  3. He says he wants us to continue to be a leading centre of new power technology adoption, but wants certainty, too, that the new technology won’t surprise us with bugs, incorrect settings and the like. Thus, he insists that he wants SA to have a mix of proven “real inertia” (aka gas turbines) and “synthetic inertia” (aka batteries and other modern control electronics) and not put trust in to just one approach.
  4. Asked if he and his team’s minds are already made up about the roles of batteries on a grid in the current Energy Plan, he quickly replied “no, it isn’t” and that he and his department are definitely open to new inputs and data proving the effectiveness of batteries in real life installations to do synthetic inertia and other tasks.

So, battery makers, the challenge is on: Show Koutsantonis that your new, charming and oh-so-high-tech battery systems can really provide synchronous inertia and the other benefits that engineers have said is possible, and on paper can be done much better by using ultra-fast batteries versus centuries-old spinning lumps of metal.

Valdis Dunis is Development Manager for The Solar Project.  

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  • Peter F

    The problem for SA is that the value of real inertia from gas turbines is almost completely offset by their negative power response to frequency changes. Worse their instability after step changes is much more likely to upset the rest of the grid

    • Alastair Leith

      There’s been some engineering modelling of various grids in USA and elsewhere that conclude a high penetration of wind generation using modern,’fourth generation’ wind turbines with primary frequency response technology built in makes a grid significantly more resilient to frequency and voltage (power) shifts than a grid with fossil generation alone.

      Looks like AEMO/SA govt is requiring that all future wind farms in SA will be required to use such turbines.

      • Peter F

        I believe that 4the generation turbines are better than older machines however the technology is relatively inexpensive and can be retrofitted at least to some extent, to most machines that are less than 10 years old. i.e the vast majority of the fleet

        • Alastair Leith

          https://uploads.disquscdn.com/images/7cae1690bc32c604d147728f8d43da9d6279f11e4c183a77fe946c20f1ed3068.png

          “Fig. 1 illustrates the four types of WTGs, starting with Type 1 (fixed speed–induction generator) through Type 4 (variable speed–full-conversion system). Types 1 through 3 are based on an induction generator; they require a gearbox to match the generator speed (high-speed shaft) to the turbine speed (low-speed shaft). Type 4 may be with or without a gearbox, depending on the type of the generator.

          The specific topologies shown in Fig. 1 are:
          • Type 1: Induction generator–fixed speed
          • Type 2: Wound-rotor induction generator with adjustable external rotor resistance–variable slip
          • Type 3: Double-fed induction generators (DFIG)–variable speed
          • Type 4: Full converter system with permanent magnet synchronous generator—variable speed, direct drive This paper details the specific aspects of inertial response by fixed- and variable-speed wind generation, highlights dynamic simulation results, and discusses the potential impact of wind inertial response on power system operation. The results of this work provide a better understanding of the differences in the nature of inertial response by wind power from the perspectives of wind turbine electrical topologies.”

          Conclusion:
          “Many factors and constraints (both technical and economic) affect the operation of a power system with high levels of wind generation. The depth of frequency excursions followed by generation loss can be improved by inertial and/or governor-like controls of variable-speed WTGs.
          In many restructured power systems throughout the world, ancillary service markets have been developed to incentivize technologies to provide the services ancillary to energy provision to support power system reliability. However, few ancillary service markets include a market that explicitly incentivizes the provision of PFR. Wind power may be an economic choice for providing inertial and PFR services in the presence of such markets.
          Inertial and PFR responses by wind power are controls that can be tuned to provide optimum performance and maximum reliability to the power system and can become a source of additional control flexibility for power system operators.”

          https://www.dropbox.com/s/fnv0zukin9eadgi/Understanding%20Inertial%20and%20Frequency%20Response%20of%20Wind%20Power%20Plants%20NREL.pdf?dl=0

  • MG

    “Batteries are sexy and synchronous” – can someone help me understand what “synchronous” means in this context? I thought “synchronous” meant “spins at 50 Hz”, full stop. Is it accurate to use the word “synchronous” to mean “supports keeping SA synchronously connected to the mainland NEM” and/or “provides services that support keeping the frequency near 50 Hz”? Different people seem to employ that term in different ways… is confusing.

    • Chris Fraser

      I thought he meant that batteries could be made to be synchronous through their energy being delivered through an electronic inverter, a perfect AC sine.

    • Chris

      You are not the only one confused about ‘synchronous’. It is indeed irony that rotating generators are described as being synchronous when in fact the problem is that they are not. The AC frequency is proportional to the rotational velocity and as loading changes the frequency may change. Indeed, if the phase changes too much then rotating equipment must be disconnected to avoid damage – in which case they are not synchronous at all. If all generators were connected through inverters locked to a known frequency then there cannot be a “frequency problem”. It is the rotating generators that cause the problem of frequency instability – not the solution.

      The issue of ‘inertia’ is also confused. The quantity of mechanical inertia of rotating equipment (particularly modern gas) is exceedingly modest. As has been pointed out by Peter wind turbines, as a proportion of power delivered, actually provide greater inertia than rotating equipment.

      Batteries also can provide frequency control (via inverter technology) and inertia through stored energy. They can respond faster to changes in load that might cause a problem with rotating equipment.

      Either those who fail to understand the benefits of batteries are intellectually challenged, or simply represent vested interests.

      • jamcl3

        “Either those who fail to understand the benefits of batteries are
        intellectually challenged, or simply represent vested interests.”

        There are a couple other possibilities:
        1) They are smart but old and this is not how grandpa maintained phase-lock
        2) They don’t trust software yet (usually a good bet, but come on already!)

  • Alastair Leith

    Why does he think “inertia” either “synthetic” or “original true blue” is the best way to balance electrical supply and demand in an age of advanced power electronics and battery storage?

  • Steve Fuller

    Frequency, inertia, synchronus, synthetic inertia? Can’t someone get an energy communicator to write these articles in a language that ordinary people concerned about emissions, grid efficiency and costs, who to believe, who crave to understand the issues and want to cast an informed vote at the next election can understand?
    Currently, my reading and my understanding are asynchronous and I feel a bout of inertia (synthetic or otherwise) coming on.