Wind 'drought' tests renewable energy poster child

Australia's renewable energy industry is experiencing growing pains. (ABC News: Daniel Mercer) Link copiedShareShare articleSpot electricity prices that soared to their maximum allowable level. Emptied batteries unable to supply a grid desperate for more energy. Dormant gas plants that fired to life and ran flat-out for days to keep the lights on. South Australia may be the country's renewable energy flag-bearer, but its embrace of the transition has been subjected to one of its sternest tests yet. For four days on the trot, a state that gets the greatest share of its electricity from wind had practically no wind at all. South Australia runs heavily on wind power. (ABC News: Nathan Morris) "Events like this are a reminder that the challenge is no longer simply building renewable generation," wrote Gavin Mooney, a former Australia manager for energy software firm Kaluza. "The harder task is ensuring there is enough flexibility in the system to manage the relatively rare periods when wind and solar output falls across a large geographic area." Indeed, the events in South Australia over the past week or so highlight the extremes that can characterise an electricity system running largely on renewable energy. South Australia was producing so much wind power on the evening of Thursday, June 18, that it was able to meet all of its needs and export surplus production. But just a few days later, overnight on Sunday, the state was almost totally becalmed. Wind accounted for just 1 per cent of South Australia's electricity needs. Virtually all of the rest was coming from gas-fired generation. And what couldn't be provided by gas was imported from Victoria, where equally calm conditions meant that state's power was being generated mostly from coal. Paul McArdle is an electricity market expert who runs specialist firm Global-ROAM. While seasonal lows in renewable energy output in winter were a known phenomenon, he noted the "wind lull" that affected South Australia last week was highly unusual. He said the state had installed wind capacity of almost 2,800 megawatts — equivalent to three large coal-fired plants. But in the four days to Wednesday, McArdle said the "rolling average" generation from those wind farms was just 124 megawatts, or an availability of 4.5 per cent. By comparison, he said wind output compared with capacity had been 5.6 per cent and 6.6 per cent during the previous two worst recorded lulls. "So, from this data, it seems safe to conclude that the recent wind lull in South Australia was the worst experienced [at least] since 2019," McArdle wrote. A major corollary of this lull was a dramatic spike in spot electricity prices. According to data from the Australian Energy Market Operator, wholesale prices hit the legal ceiling of $20,300 a megawatt hour twice during the episode. Average wholesale prices in South Australia were $88 a megawatt hour in the first three months of the year. The first was on Monday evening after the sun had set and as the wind stayed still. Crucially, batteries appeared unable to stop wholesale prices getting out of hand. In a post, Australian firm OptiGrid said battery owners "discharged heavily through the afternoon and early evening, chasing the gradual rise in prices". While many batteries were running low as the price climbed higher, "around half managed to catch the first extreme price interval". Batteries struggled to fully recharge during the extended wind lull in South Australia. (ABC News: Mya Kordic) Crucially, however, almost none were able to capitalise the second time prices spiked to $20,300 a megawatt hour the next morning. Some batteries were even charging as prices soared, paying up to $10,000 a megawatt hour to store electricity that was overwhelmingly coming from gas generators. "Despite another period of $20k prices, relatively little battery capacity was able to respond," OptiGrid noted in its post. Making matters worse, constraints to the high-voltage transmission network meant South Australia was exporting electricity to Victoria even as its prices rocketed. Jess Hunt, an electricity market designer, wrote that such "counter-price flows" were not helpful. "This seems to have been happening a lot lately, but the outcome [on Monday] was particularly painful," Hunt posted. "By 8pm our batteries were drained and we hit the market price cap." New transmission lines are designed to better integrate South Australia with the national grid. (Supplied: Elecnor Australia) Geoff Eldridge, an electrical engineer who runs consultancy Global Power Energy, said the prolonged lack of wind in South Australia was a "stress test" for its electricity system. Eldridge said a single day of low wind and solar output could create volatility, but a four-day lull could examine the resilience of the grid. "Batteries, gas, imports, interconnector capability and demand response all become more relevant," Eldridge wrote. Eldridge said the past

Wind 'drought' tests renewable energy poster child

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Wind 'drought' tests renewable energy poster child

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