The Australian battery power storage facility was already the biggest in the world, now it's even bigger.
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The world’s biggest lithium-ion battery, Tesla's Hornsdale Power Reserve in South Australia, has received a capacity bump of around 50 per cent, courtesy of a major expansion project that promises to bring even more reliability to the state's grid.

Electric carmaker Tesla and its partner Neoen, the French renewable energy provider that owns the reserve, have completed a project deploying more storage capacity at the site, which is located in Hornsdale, north of Jamestown, in South Australia.

"Hornsdale Battery Extension: network connection works completed! The world [sic] biggest battery to provide soon extra reliability to the grid in those extremely challenging times (very low demand, increased risks of outages, ...)," Neoen tweeted earlier this month.

The expansion project, which was known as the Hornsdale Battery Extension, has added 50 MW or 64.5MWh of capacity to the site, raising its total capacity from 100MW/129MWh to 150MW/193.5MWh.

That comfortably outdoes any other lithium-ion storage projects around the world, according to PV Magazine, with the next closest competitor being the Stocking Pelham facility in the United Kingdom, which offers 49.99MW of battery storage.

The plant entered into operation in December 2017 after Tesla CEO Elon Musk made a Twitter bet with Atlassian CEO Mike Cannon-Brookes that he could build it in 100 days from a contract being signed, or else make it free. The plant's construction followed a series of major blackouts in South Australia from 2016 to 2017.

Roughly a year after the plant opened, Neoen revealed the entire project had cost 56 million euros, or AU$95.8 million – with the ongoing cost to taxpayers estimated to be roughly $4 million each year for the next decade.

Since then, however, the Hornsdale Power Reserve has shown tangible return on investment and was estimated to have made revenues of around $25-26 million in its first year, according to the ABC.

In 2018, Godart van Gendt of advisory body McKinsey and Co revealed at an energy industry conference that in its first four months of operation, the Tesla reserve had cut costs in the state's frequency ancillary market by 90 per cent, according to Renew Economy.

Frequency control and ancillary services, or FCAS, consists of a system of mostly steam turbines and gas generators that kick in when there are problems or maintenance being carried out on Australia's power grid, thereby pushing rates up during those periods.

However, as reported by Electrek, Tesla's battery system "can provide the same service cheaper, quicker, and with zero-emissions".

According to Mr van Gendt, “the 100MW battery has achieved over 55 per cent of the FCAS revenues in South Australia. So it’s 2 per cent of the capacity in South Australia achieving 55 per cent of the revenues in South Australia".

This is despite frequent and widespread criticism of the power reserve from the state government.

"[T]he previous government's implementation and delivery of the battery was incredibly messy and overly expensive," Energy Minister Dan van Holst Pellekaan told ABC Radio Adelaide in 2018.

In March 2018, Australian resources minister Matt Canavan also memorably compared the Tesla power reserve to reality star Kim Kardashian, saying: "It’s the Kim Kardashian of the energy world: it’s famous for being famous. It really doesn’t do very much."