August outages underline risks to the reliability of the national grid
Summary: The operator of the national electricity market has warned of risks to the reliability of the power system after several interconnectors blew without warning last August, causing blackouts and isolating two states from the grid.....
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Queensland and South Australia were exporting power across the interconnectors when a lightning strike caused them to trip simultaneously on August 25, forcing electricity to be cut to big industrial users and retail customers in NSW and Victoria.
The Australian Energy Market Operator said several generators failed to respond as expected including “counter-productive responses” that could have been limited or prevented if sufficient frequency control settings were enabled in each region.
While Tesla’s giant battery was praised for helping to stabilise frequency, four unnamed wind farms in South Australia reduced their output to zero because of incorrect settings while solar rooftop systems also crashed out and were unable to assist in boosting supply to either Victoria or NSW.
AEMO detailed how 15 per cent of sampled solar systems installed before October 2016 dropped out during the event. Of those installed after that date, nearly a third in South Australia and 15 per cent in Queensland failed to meet standards.
The nation’s biggest single-site power user, the Tomago aluminium smelter in the NSW Hunter Valley, lost power without warning, halting two pot lines for up to an hour. Alcoa’s Portland smelter in Victoria lost power for about 50 minutes.
Unplanned power outages at aluminium smelters can be disastrous, but both affected plants managed to restart operations without damaging valuable infrastructure.
Thousands of households across NSW lost power and the outage caused signalling problems and delays on Sydney rail networks.
AEMO has prepared eight recommendations including new rules to be put in place by mid-this year to provide primary frequency control services that are not currently required for the national electricity market.
“AEMO has identified specific risks that compromise the power system’s resilience to major frequency events,” the operator said in a report released yesterday. “The event highlights a deficit of primary frequency control response from NEM generation, compared with historic levels and with other power systems around the world.”
The findings highlight the challenges ahead as the market operator seeks to integrate a surge of cheap but intermittent renewable energy supply within the national grid to compliment existing baseload generation.
About 2100MW of new capacity was added into the system last year, including rooftop and commercial solar, wind farms and big batteries in South Australia and Victoria.
Renewables for electricity generation surged by 23 per cent in the September quarter over the previous three months and accounted for just over 13 per cent of generation in the national electricity market, according to consultancy EnergyQuest.
The rapid switch to renewables is having a profound impact on the grid, with solar generation jumping by 38 per cent in the three months to September while wind grew by 16 per cent, displacing gas from the grid’s power mix. Hydro power was at its highest level in more than five years.
A rapid shift in Australia’s electricity mix to renewables from coal over the next decade may threaten the security of the nation’s power grid if poorly integrated, the International Energy Agency warned last month.
It is estimated that about 90 per cent of the $88 billion forecast to be spent adding power capacity in Australia until 2040 will be outlaid on clean energy, according to Bloomberg New Energy Finance.
Just 2 per cent will be spent on coal, with that investment more likely to keep existing, ageing plants running than bringing in new coal-fired power stations.
That influx of cheap but intermittent supplies of wind and solar threatens to undermine ageing baseload coal generators in the national electricity market, which now produce about 75 per cent of generation on the nation’s east coast.