Many are surprised to know that Tomago Aluminium is a major electricity consumer but few realise we play a major role when it comes to keeping the state's lights on.

Over summer, as the weather hit record temperatures, bushfires were doing their worst and air-conditioning units were running overtime, the pressure on the NSW electricity supply was enormous.

With the stability of the grid under threat and a reliable supply uncertain, Tomago was asked to help out by the Australian Energy Market Operator and energy supplier AGL.

And help we did, carefully cycling the potlines, shutting them down as necessary and acting as a ‘virtual battery’ to redirect that considerable load during the peak afternoon period.

Over three critical days in January we stopped all three lines for just over seven hours. On top of that, we had two separate substation component faults that led to widespread outages across the whole site. In real terms, Tomago was able to put a staggering 600 megawatts of electricity back into the power grid.

In total, we experienced almost 11 hours of interruptions to the potlines and that, said Tomago Aluminium CEO Matt Howell, is unheard of.

“We’ve never had that many outages in one month, but it is better to do it that way than to have a cascading series of (electrical system) trips,” he said, adding: “There are many things that can cause outages and if you don’t have an aluminium smelter handy, who do you call on?”.

The alternative is, rolling blackouts for households. In a worst case scenario, if the whole NSW system shut down, it would take more than five hours to re-energise us, which is about two hours too late to prevent a potline freeze.  A truly sobering thought.

While strategically switching-off the potlines was able to keep the power on for the rest of the state it did cause its own set of problems for Tomago.

Each shutdown put the smelter several hours behind on its work schedule and the thermal instability took many weeks to recover from. “I take my hat off to the men and women who were working in extraordinary heat to recover from these unplanned outages; their efforts saved all our jobs.”

Matt says smelters interrupting operations to secure electricity supplies for the broader community are not unusual, adding that co-ordinated interruptions, better known as load-shedding, are best done in a planned way rather than in ways that will cause blackouts.

“We can take a potline off for an hour but beyond that the risk of bringing it back online successfully increases dramatically. In January 2016 a failed restart came within a whisker of freezing that potline.”

The biggest problem in the future, according to Matt, is that the summer shutdowns needed to help the state stave off power outages will not simply continue, but increase in their regularity.

And that is food for thought.

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