Tesla big battery is changing the way people think about the grid

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Tesla big battery is causing a rethink about the way the grid is managed. It will already become a front-line defence in a new mechanism designed to prevent black-outs and load-shedding in the event of a major fault.

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The arrival of grid-scale battery storage in Australia was a long time coming, and a little time tweeted, but the presence of the world’s biggest lithium-ion battery in South Australia, and its performance in its first few months is every bit as exciting as its boosters hoped – and its detractors feared.

The Tesla big battery is possibly the most bally-hooed installation in Australia’s electricity grid for the last half century.

But the excitement, from its owners and developers, from competitors, analysts and grid operators, is as exciting as it is infuriating for those who seek to dismiss it.

The speed and accuracy of the battery has already been noted, both by its engineers and owners, and the grid operator, as has its ability to flex from charge to discharge in a matter of seconds.

And because it is a fully dispatchable installation, it can now take some of the stuffing out of the bloated markets that were dominated, controlled and extorted by the fossil fuel incumbents, as the company itself, the politicians who contracted it, and the market operator have noted.

And there’s more.

The Australian Energy Market Operator is now looking to the Tesla big battery – and others like it – as its first line of defence against the kind of potentially catastrophic events that triggered the blackout in South Australia more then 18 months ago.

The Tesla big battery – officially known as the Hornsdale Power Reserve – will play a front-line role in a new mechanism called the System Integrity Protection Scheme (SIPS).

These schemes could be based almost entirely on the ability of these batteries to swing into action at a moment’s notice in response to a major fault (such as the tripping of a big coal or gas generator), and literally hold the grid together while slower moving conventional machines get into gear.

The idea is to stop the big interconnectors from tripping off – and leaving states such as South Australia islanded and at risk of massive load shedding, or worse.

“This is a step change for us,” Damien Sanford, the head of operations at AEMO, tells RenewEconomy in an interview. “The battery enables us to inject energy into the system in a matter of milliseconds.

“It is fantastic for that kind of control,” he adds, noting that it means that the operator does not need to trip off so much load. In other words, it doesn’t have to cut supplies to major users such as BHP’s Olympic Dam  or other manufacturers.

“The risk of load-shedding will be further reduced as more batteries come onto the grid, and contribute to this new scheme,” AEMO’s recent assessment of the first few months of the Tesla battery concluded.

This new system – to be implemented this quarter – will be able to call on the full 100MW discharge capacity of Tesla big battery. It will only need minutes of storage – (in fact only 10MWh of the 100MW/129MWh battery is set aside for this purpose) – but it is enough to create time for other machines to respond.

Detractors of the battery storage system – and there are many, particularly among proponents of coal-fired generators – have taken a one-dimensional view of the technology and chosen to completely ignore the battery’s speed, accuracy and flexibility.

They argue that if the battery is not capable of meeting peak demand for more than a few minutes, then how could it possibly be of use. It’s a nonsense argument, of course, but one they repeat endlessly.

But the Tesla big battery’s new role in the SIPS program, and the display of speed and versatility and flexibility elsewhere in the grid means that for AEMO, and other players in the energy market, the game is changing quickly.

As we reported earlier this year, the new technology is so quick it has left rule-makers in its wake. Many of its abilities – such as the speed, the accuracy and the versatility – are not valued in the grid because the technology has never been seen before.

AEMO is keen to look at modifying rules that will actually ascribe value – very fast frequency response, ancillary services and other specifications. It has cited similar rules in overseas markets, particularly in America, although these would need to be adapted to suit the local market.

It is also looking at a potential performance system, rewarding batteries or other technologies for their faster and more accurate response to system faults. Right now, they get little more than a pat on the back. (See this story to show how this graph above compares with conventional turbines)

“We are pretty excited about range of batteries coming into the NEM (National Electricity Market,” Sanford says.

“And we are genuinely excited about the types of services that batteries can provide. We will actively pursue those changes to enable greater participation by these batteries, and similar fast responding technologies.”

And other battery storage systems are on their way. The new battery alongside the Wattle Point wind farm in South Australia should be on line within the next month, and will be followed in the next year by a battery at the Lincoln Gap wind farm, and then with the Snowtown and Whyalla solar farms.

In Victoria, three large batteries are being installed, one at a new wind farm near Stawell, one at a new solar farm, and another at a centralised grid connection point.

Sanford expects the amount of grid-scale storage set to participate in the “regulation” FCAS market could amount to more than 1GW, which will play a crucial role as more synchronous plant exits the market.

Hybrid solutions are also emerging – these are the batteries that are deliberately paired with wind and solar farms to smooth out the intermittency of their output.

Sanford is also excited about the speed with which the battery responds to the contingency market, and the fact that storage can be commissioned so quickly, can be built without the need for new connection points, and because it is modular – meaning they can be big or small, or anything in between.

“The speed at which we can deploy these things …. And the scale that they can be rolled out is pretty exciting.”

And battery storage will play a key role at the consumer level too, as more households and businesses add battery storage to get the best value out of their solar systems, reduce their exposure to the high cost of grid power, and secure back-up needs.

Storage, Sanford says, will play a key role in dealing with the system peaks, which are being pushed by rooftop solar further into the evening, and to deal with the increasingly high “ramp rates” caused as by fluctuations in weather-dependent output.

“Once we work out how to integrate large volumes of battery storage, we are going to start to see some great outcomes,” he said.

Was AEMO surprised by the success of the Tesla big battery?

“We were not surprised by it. I think we had some pretty high hopes, around what it will be able to do.

“That explains why we were heavily involved with some of the controls on the battery when it went it.

“I wouldn’t say we were surprised with what we been able to do – South Australia is pretty unique, and the battery technology in that unique environment has given insights into what may be applicable around the NEM.”

And if the battery had been there in September, 2016, would it have prevented the blackout as some have suggested?

“I wouldn’t like to speculate on whether would they would have avoided the system black,” Sanford says. There were simply too many variables, and any such conclusion would need to rely on detailed analysis.

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