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What is the Tesla big battery actually selling? It’s not just energy

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The Tesla big battery has been a point of fascination for many in the energy industry since its official opening at the start of the month.

Everyone, from the market operator down to generators, consumers, competitors, the owners of soon-to-be-redundant incumbent technologies and, one suspects, Tesla itself, is keen to know exactly how it will operate.

One of the common inquiries we have received since updating the popular NEM-Watch to incorporate the Tesla battery, and its ability to both charge and discharge in rapid time, has been “why isn’t it doing anything?”

Appearances can be deceiving. One part of the big battery’s function is to do what gas peaking plants do, and fire up in times of peak demand (and high prices) – although firing up is not quite the word here.

Let’s remember that most gas peaking plants operate for just a few hours a year, when prices are really high.

SCADA

The Tesla battery will be able to operate more often than that, because it’s ability to charge at low prices, and then sell into the market at higher prices, means more opportunities for it to be used.

This table above is an example. Charging the battery (HPRL1) with lots of wind blowing and then in the next five minutes offering to discharge (generate).

That also means it doesn’t have to wait for the huge price spikes, the surge in demand and “scarcity” in supply to justify its operation.

But that’s not the only thing it can do. It also plays a less visible role of providing important network services such as frequency control and ancillary services (FCAS). This is a completely different market – in fact, about six markets – and they are not visible on the energy only market.

tesla battery regulationDylan McConnell, from the Climate and Energy College in Melbourne, has helpfully provided these graphs to illustrate exactly what the Tesla big battery is up to in certain times.

The trick here is that Tesla is actually providing a service, it is not necessarily putting this output into the grid. If called on, it will, but most of the time it is there for exactly what these services are called – contingency and regulation.

Contingency, McConnell explains, are for those events when a large power station trips off, and the battery can act quickly to “hold the grid’ together while bigger but slower moving machinery is fired up.

Regulation is basically the throttle controls that the Australian Energy Market Operator wants to be able to deploy to make the minor adjustments needed to keep the grid stable. The battery, like other spinning machinery, offers these services – and is paid for them – but is mostly on standby.

hornsdale power reserve copy
Seen together, this is what it looks like. The actual generation, (in darkest shade) is actually just a fraction of the total offering, but will be the only one visible on the energy market pages.

  

Pocket
  • Andy Saunders

    Would be great to see some prices overlaid…

    • Rod

      Agreed. I would like some indication of how much this might be saving SA.
      I also can’t see much value in arbitrage with the spread I am seeing most days.

      • Andrew Roydhouse

        It is also acting in a game of chicken with the various generators. Over the next few weeks they will be trying to work out what its ‘tripping’ points are for the FCAS services and then seeing if they can ‘spring’ those before exhausting its ability to offset their games.

        Then they can ratchet the prices up to generate the super normal profits they’ve become accystomed to since late 2015 when the game suddenly changed for some reason.

        The game of cat and mouse is on.

        • Rod

          I’m not a license holder but would be interested to see if they are jumping in during our 11:30pm HWS peak.

          • rob

            Probably that too…. but I reckon more so in the arvos when all the air cons come on and where ever else they see a spike!
            I’d be very happy indeed to see 10 more built……that would real [email protected]@K with the gentailers.

  • Michael Murray

    Could see it charging on nem-watch earlier today.

  • jeffhre

    “Contingency, McConnell explains, are for those events when a large power station trips off, and the battery can act quickly to “hold the grid’ together while bigger but slower moving machinery is fired up.”

    What if the grid can’t be “held together?” Where does assistance with a black start fall on this Regulation-FCAS-contingency continuum? Will they be paid for such a function?

  • Barry Alternative Fact Covfefe

    If it does not show real time full info perhaps a weekly or monthly summary graph with dollars if possible?

  • Malcolm M

    Batteries could also help get more capacity from our inter-connectors, which are currently limited to 50% of their thermal capacity. This is so if one circuit trips the remaining circuit can maintain power flows until more local generation can be dispatched. For example, the SA/Vic inter-connector via Heywood consists of 2 circuits with a thermal rating of 650 MW each. When the Heywood upgrade is completed the plan is for the total operational limit to be 650 MW. If there were a combination of batteries plus instant demand response, the operational limit could be increased to 1300 MW without building new poles and wires, only batteries and control systems

  • MaxG

    I’d like to see more of these batteries around the country 😉

  • neroden

    “Contingency” must pay better than “regulation”. Looks like the battery has some trouble bidding into both markets at once — the regulation bidding drops when the contingency bidding starts.

  • Sir John Maga

    If the grid responded to the outage in 4 seconds, can somebody explain what part
    the Tesla battery’s 7 mw played in this event?