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Could household battery storage have prevented SA blackout?

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Energy experts are still scratching their heads about what they could have done to prevent the massive, state-wide blackout that occurred in the midst of a one-in-50-years storm last month. The answer may lay inside South Australian homes. Or at least, it should do. And it’s battery storage.

Dean Spaccavento, the CEO of Australian energy management software company Reposit Power, says battery storage placed in thousands of homes in Adelaide and the surrounding region – and linked through smart software – could have provided the emergency supply to help stabilise the network at its moment of crisis.

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Image courtesy of Off-Grid Energy Australia: offgridenergy.com.au

In a matter of seconds, the interconnector became overloaded as it made up for lost power on the South Australia network following the catastrophic series of events that saw three of the main transmission lines disconnect as pylons crashed to the ground.

Battery storage, Spaccavento says, could have provided the emergency system back-up. “That would have stopped the cascading dominoes,” he says. And not a lot would have been required.

To provide 50MW, possibly enough to prevent the Heywood line from going over its overload capacity, the number of homes with linked battery storage would have to have been around 12,500. If the amount needed was 250MW, then it would have required 50,000 households. Around 200,000 households in the state already have rooftop solar.

Reposit Power’s comments are timely, given that the state and federal energy ministers are meeting tomorrow, and on their agenda is a report from the CSIRO about battery storage.

Hopefully, it will be a little more up to date than the AEMO chairman’s report at the last COAG meeting a few weeks ago, when he said that battery storage would not be competitive for up to two decades.

ACT energy minister Simon Corbell found those comments remarkable, and wrong. And as David Leitch writes in this analysis (and advice to federal energy minister Josh Frydenberg advisors) battery storage may already be commercial. Certainly, some networks think so.

Indeed, Reposit Power has written a letter to the ministers asking them to consider the role this aggregated clean energy system plays in keeping the grid balanced.

Reposit’s COO Luke Osborne said “Australian households can provide a cheap and bullet-proof solution to ensuring Australia’s future energy stability.”

The idea that storage could have helped avoid the crisis is not new. AGL, which operates the biggest gas generator in the state, said earlier this week that the best way to offer energy security was through distributed generation and storage and micro-grids, and this could only happen with renewable energy.

That’s the trick with battery storage, to unlock its value streams; no easy task in a grid designed to operate with decades old technology and even older thinking. AGL is having a go, by trialling a scheme that links household storage to make a  “virtual power plant”, and SA Power Networks is conducting trials of its own.

The attraction is that much of the investment for battery storage would come from the households themselves, although the government might want to consider subsidies to reduce the cost.

Providing these services – responding to peak demand and providing emergency back-up, can add to the revenue stream of the battery owner, over and above the time shifting they use for their rooftop solar.

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In a briefing Reposit Power wrote for Senator Nick Xenophon, Spaccavento said system security would be increased with each added (linked) battery, and it would mean added value to households and increased private investment in the grid.

“Scaling of this business model will solve South Australia’s grid instability,” the briefing said. But it said initiatives, such as the ACT government’s “Next Gen” battery storage program, would accelerate the uptake and help overcome market barriers.

Osborne, who used to work for a wind energy developer and lives under a wind farm, says the interim reports into the outage from AEMO have shown that South Australia’s energy infrastructure was not strong enough for the force of the fierce storms of September 28.

Transmission lines fell, some wind farms lost output, more than half of the state’s gas capacity was offline or unavailable, or simply too slow to respond. And when the interconnector became overloaded, it too disconnected.

What an energy market operator needs most of all in a crisis is time. The interim AEMO report shows that the crisis played out in less than a minute, the most dramatic events occurring in the space of a few seconds, or even fractions of seconds.

That’s what makes battery storage so attractive. It can respond in milliseconds, providing network support, or outright power – sometimes for only short periods of time. But quite possibly enough for the operator to marshal its defences and get slow-moving gas generators online and other support.

Spaccavento points out that battery storage could not be expected to power the state for any lengthy period. It is designed to hold the system steady for a short period of time so the operator can look at other long-term solutions.

“On September 28, we don’t know what happens next. But storage could have given the operator time to find another option,” he told RenewEconomy.

One of those options could have been creating enough time for the unused gas generation to ramp up and provide more capacity, reducing the load on the interconnector. Although, frankly, there was no of knowing what the impact of the transmission lines would have been.Screen Shot 2016-10-06 at 2.25.29 PM

Spaccavento says, however, that the grid had held up remarkably well considering what was thrown at it.

“This was pretty much a power system apocalypse,” he said. “It’s amazing that it stayed (online) as long as it did. The state got torn apart.” And, he noted, it was interesting that no wind farms tripped, and most of their capacity was still there until the interconnector failed and all generators tripped at the last moment.

Osborne compares what happened in South Australia to the children’s book “Who sank the boat”. That’s when “a cow, a pig, a donkey, a sheep and a tiny mouse go for a row, but one of them sinks the boat.”

The mouse is blamed because it was the last one in. It was kind of what happened in South Australia – it was the last 50MW strain on the interconnector that eventually ended all resistance, and the system sank.  

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  • Peter F

    In some ways the answer is more complicated because it depends a bit where the batteries are. If they are “behind” the fault they are no help to prevent the fault happening although they should speed reconnection. On the other hand Electranet has 400 Zone substations. It makes a lot of sense to put 1-5MW of storage each in many of them to reduce investment in peak poles and wires, so you can easily have 500-1,000 MW on line just from that source alone.
    National grid in the UK has just awarded contracts for 200MW of batteries for grid stabilisation. It turns out most of it is located in thermal stations not just to give them time to ramp up but to actually be able to sell more peak power because during the peak half hour they are selling generator + battery power at top price and then they can recharge the battery during a gentle ramp down early ramp up or even recharge the battery with excess power from elsewher on the grid if the spot price is less than their fuel cost

    • Kenshō

      In Australia it sounds like batteries + large fossil fuel generators = increased ability to exploit and game the market. Zone batteries distributed throughout the network, sound like a much more resilient grid in terms of adding frequency stability in storms and adding stability to wholesale electricity markets.

    • JeffJL

      A few big batteries would be cheaper and more efficient than lots and lots of small ones.
      Better to throw the resources at big storage than home storage.

      • Peter F

        In effect that is what I said. At the moment the biggest batteries are in shipping containers. It does not make a lot of difference to the cost if we have 1,2 or 3 shipping containers at 200 sites or 200 containers at 2 or 3 sites. The later might save a few percent in installation time, the former will reduce peak transmission losses and make the grid more robust.
        Re small batteries there are arguments for all sorts. Street corner batteries next to the transformer would also be more efficient but by the time all the admin issues are solved and the utilities take their cut it will not be much cheaper than installing premises batteries. Many people will want to install their own batteries to have independence so that is what they will do. Just like people want two cars when society would be far better off if we had less cars and more public transport

        • JeffJL

          Apologies. The post was suppose to be backing you up not having a go.

          • Peter F

            No worries, clarity is not my strong suit

  • Cooma Doug

    The thing I have been saying here for years, batteries switched in millisecond timeframes to support system disturbance is not anywhere near as expensive as peak gas.
    Reasons for this are the speed of response and the ability to discharge at higher then the kwh rating. I kwh battery could be discgarged at 3kw.

    So when looking at the comparative cost to peaking gas plant as an ancilliary service, divide it by 3 for a start and then deduct the reduced infrastructure cost. It gets rediculous to continue with the Grid side responses using large fossil fuel plant.

  • suthnsun

    They should look at PJM network in US, many battery storage installations of different types providing frequency correction and grid support with a well recognised signal/bid/compensation system operating in milliseconds.

  • john

    If sufficient battery back up had been put in place perhaps but on a micro level within a small area yes with battery backup they could have islanded and removed themselves from the grid not hard to do.
    For instance i have enough land to put PV and battery system in to power the street should i but?
    It would perhaps cost upwards of $200k is it worth it to do this or should we all get together and fund the proposal?

    Interesting actually let us look at the proposal and explore the cost point when this become viable.

  • Peter B

    Batteries are a great idea as long as they don’t require people in Social Housing, Commercial rentals or other taxpayers to subsidise them! Unless of course you can prove it will lower their ongoing cost of electricity.

    • Peter F

      If people who install batteries for their own use are allowed to participate in the real time market that will drive down peaks and therefore average power costs so everyone should be better off as the Transmission and distribution investment can be lower while installation and very rare use of gas peakers can be eliminated

  • Kenshō

    Great analogy for the describing how a grid can get overloaded, without blaming any single generator.

    • DJR96

      Quite right. I’ve read the AEMO interim report too and it was clear that the black system was not the fault of any generation be it fossil fuel or wind.
      It all went down when the load on the interconnect to Vic became “over-capacity”. However, the rating of the interconnect is calculated for worst case scenario ie 50 degree summer scorcher. Only during this event it was probably 40 degrees less than that and could safely handle the 850-900MW load for some time. Long enough to implement load-shedding strategies at least.
      Tripping capacity ought to be temperature sensitive. Just a thought.

  • Kenshō

    My concern with the kind of utility interacting software discussed is whether customers can subscribe without a contract, or sign a contract for a period of time, then have their local equipment reprogrammed to not interact if the deal becomes sour. I think the utility should also not drain the customers battery beyond a certain % no matter how bad circumstances become for the utility, otherwise there would be potentially no resilience left in the community at all if a region goes down.

    • solarguy

      My thoughts exactly, no point having a household storage system if some one else pilfers it all.

  • Matt S

    Local contingency FCAS provided by Interruptible load would be a much much cheaper alternative, and it would enable greater transfers on the Heywood interconnect thus forcing wholesale prices down also.

    Its rapidly deployable, economics are great and it’s significantly faster to respond.

    You just need a regulatory environment that allows it.

  • qldnico

    Tidal energy could be the solution to supply electricity at times of peak demand. No need for batteries which have to be replaced however Australia have always big tides in the north and strong currents in the south (e.g. Darwin, Torres Strait and Bass Strait).