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How Australia survived its second-hottest summer without load-shedding blackouts

By political reporter Nick Harmsen, Wednesday May 23, 2018 - 18:52 EST
ABC licensed image
Temperatures were 1 degree Celsius hotter than average over summer. - ABC licensed

Australia's electricity grid survived the second-hottest summer on record without load-shedding blackouts, despite the closure of a major coal-fired power station in Victoria, according to two reports released on Wednesday by the Australian Energy Market Operator (AEMO).



The rapid closure of the Hazelwood coal-fired power station in Victoria last year drove up power prices in southern states and put pressure on the market operator to deliver enough power to meet demand on summer's hottest days, particularly in South Australia and Victoria.

But a review of AEMO's summer operations shows the national grid escaped the summer relatively unscathed.

Here's why.

It was hot, but not as hot as it could have been

According to the Bureau of Meteorology, the summer of 2017-18 was the second-warmest on record. But the exceptional warmth was the result of prolonged widespread low-intensity weather rather than individual heatwaves.

AEMO reported that in Sydney and Brisbane, the weather was cooler than the record heat experienced in the first quarter of 2017. Adelaide's summer was hotter than a year earlier, while Melbourne was largely unchanged.

Heatwaves are a huge driver of electricity demand. In the end, the average demand across the grid was 1.5 per cent lower than the corresponding period the previous year.

Victoria was the one region in the national grid to increase demand, driven by the warm conditions and increased industrial load.

In total, AEMO declared a so-called "Lack of Reserve" in the power grid 31 times over summer. But none of these events resulted in a load-shedding blackout.



Other generators filled Hazelwood's void

Hazelwood's closure in March 2017 saw 1,600 megawatts of power supply capacity (more than half SA's peak demand) sucked out of the national grid.

But when supply tightened, other power stations helped fill the void. Gas-fired power stations in SA, Victoria and Queensland were brought out of mothballs, adding 833 megawatts of additional capacity.

The risk of summer blackouts also prompted political action — temporary diesel generators were installed in SA and Victoria, adding another 274 megawatts of capacity. State government subsidies helped deliver 100 megawatts of Tesla battery power in SA.

The market operator also took emergency measures — issuing contracts for a further 867 megawatts of "demand response" across the southern states.

In short, AEMO signed agreements with factories, refineries and other businesses who were willing to be paid to power down at short notice, if there wasn't enough electricity to go around.

Coal stood up. So did solar. So did high voltage power lines

Much attention has been drawn to the fact that many of Australia's coal-fired power stations are old, and there were some high-profile instances where individual generators tripped out in the summer heat.

But AEMO points out that the coal fleet generated at its highest level in a decade. While there was less brown coal-fired generation on an absolute basis doe to the retirement of Hazelwood, the remaining brown coal-fired plant increased average output by 198 MW and black coal-fired generation increased by 382 MW on average.



AEMO attributes at least part of this down to scheduling planned maintenance outside the summer months.

Rooftop solar generation continued to grow — the daily maximum of rooftop photovoltaic generation increased by 16 per cent year upon year.

There was also a big reduction in the number of unplanned outages on transmission lines, making it easier for the market operator to make sure power was where it needed to be when we needed it most.

There was enough gas to get by

Last year Australia faced dire warnings of domestic gas shortages, but after , it seems there was enough to get by.

Much of the gas consumed by power stations in the National Energy Market comes from the Longford gas plant in Victoria.

On the eve of the start of summer, that plant suffered an unexpected outage, on a day where AEMO had already forecast an extremely tight balance between supply and demand. In the end, the market operator intervened in the gas market, to guarantee supplies.



The system was very carefully managed

Prior to summer, the market operator took the unusual step of activating special powers known as the Reliability and Emergency Reserve Trader — or RERT for short.

These powers gave AEMO the right, if needed, to switch on additional generation outside the National Electricity Market, or switch off power to certain customers who volunteered to be paid as part of the RERT scheme.

For the first time in the history, the market operator actually activated these powers — twice — on November 30 and January 19.

AEMO says the scheme cost $51.26 million to deliver, adding about $6 to the average annual household power bill.

The robots are helping

In February, AEMO began using "machine learning" to improve its forecasts for when the supply-demand balance in the National Electricity Market is tight.

The new system wasn't used for forecasting last summer.

But if it had been, AEMO would have adopted even more conservative assessments — and would have activated its RERT powers earlier and more frequently.

The market operator has emphasised that the flexibility it enjoys through this system provides an "invaluable insurance policy" against credible weather and demand changes.


- ABC

© ABC 2018

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