A local renewable energy skeptic recently wrote that a blackout in Australia proves wind energy isn’t reliable.
When several wind farms shut down at once in bad weather, it plunged an entire state into darkness. Naturally, I had to investigate.
The massive power outage in South Australia in the wake of tornados last September immediately led to partisan bickering. Did the state’s heavy reliance on wind energy cause the blackout?
The Bureau of Meteorology (BOM) issued a report on the tornados that swept the state. The Australian Energy Market Operator (AEMO) issued four reports that explained the events that led to the outage.
While I haven’t studied the entire AEMO report, I did extract details not included in any of the newspaper stories I read. Both political parties, and AEMO itself, ought to be ashamed of the way they shaded facts to make themselves look good.
Generally accepted facts about the South Australia blackout
The State of South Australia relies far more on renewable energy than any other Australian state. It gets about 40% of its electricity from renewables, and most of that from wind energy.
I find that it has 19 wind farms in operation, with more in various stages of development. Three came online since the blackout of September 2016. Three more apparently operate outside the area that experienced the bad weather.
Unlike the more densely populated areas of the US and Europe, most of South Australia’s electric distribution system is above ground.
On Wednesday September 28, 2016, seven tornados swept across South Australia. Two of them simultaneously destroyed three transmission lines (and more than 20 towers that supported them).
According to the BOM report, the two that destroyed the transmission system had wind speeds that approached those of Hurricane Katrina.
Six voltage disturbances within two minutes caused nine wind farms to shut down, which resulted in a loss of 445 MW of generation.
The drop in electricity caused the Heywood Interconnector to shut off in order to protect the rest of the National Electricity Market (NEM). By 4:16 pm, the entire state of South Australia, some 850,000 customers, blacked out.
Power returned to some customers by 7:00 that evening, but not all customers had electric service restored until October 11.
A heatwave in February 2017 caused another blackout in South Australia.
The Australian Energy Market Operator (AEMO), a government body, has responsibility for overseeing delivery of gas and electricity. It operates the National Electricity Market (NEM). It investigated and issued four reports on the disaster.
So, did the destruction of the transmission towers and lines cause the blackout, or was it that nine wind farms shut down?
Politics and finger pointing
The more liberal Labor Party controls South Australia’s state government.
Renewable energy skeptics gravitate to the Liberal Party, while proponents support the Labor Party.
The federal government issued statements that blamed the blackout on South Australia’s excessive reliance on renewable energy.
The Labor party accused the Liberals lying, insisting that the government had been specifically informed that weather caused by climate change, not wind energy, caused it.
At the state level, South Australia’s Energy Minister claimed that the BOM report verified that the weather caused the blackout and called on opponents of renewable energy to accept that fact.
The state’s opposition energy spokesman responded that the BOM had not attempted to investigate what caused a statewide blackout and did not explain why the collapse of transmission lines in the north of the state caused a statewide blackout.
“I’ll wait for the final AEMO report,” he said, “but I note that the wind farms were the first generators to go down, the interconnector was next and the gas generators were the last.”
The final report appeared in March 2017, but politicians and interest groups sparred over three preliminary reports. In fact, both sides cite the report to back up their conclusions.
The AEMO report
The generation mix now includes increased amounts of non-synchronous and inverter-connected plant. This generation has different characteristics to conventional plant, and uses active control systems, or complex software, to ride through disturbances. With less synchronous generation online, the system is experiencing more periods with low inertia and low available fault levels, so AEMO is working with industry on ways to use the capability of these new types of power generation to build resilience to extreme events.
As the generation mix continues to change across the NEM, it is no longer appropriate to rely solely on synchronous generators to provide essential non-energy system services (such as voltage control, frequency control, inertia, and system strength). Instead, additional means of procuring these services must be considered, from non-synchronous generators (where it is technically feasible), or from network or non-network services (such as demand response and synchronous condensers).
And until the industry learns to deal with these differences, it will experience more problems.
But relying entirely on conventional technology for voltage control, etc., is not an option.
Most of those who blame the blackout on the wind farms fail to note that the AEMO report also criticized the operation of two gas-fired plants.
They were supposed to come online to reenergize the state’s power network. They failed to provide the expected service to restart the system.
AEMO’s contribution to the blackout
AEMO itself appears to be part of the problem.
Wind turbines are equipped with “low-voltage ride through” settings.
When voltage dips too low, a turbine can’t work correctly.
The software that controls them is supposed to prevent it from disconnecting from the grid.
Normally, these conditions don’t last long and don’t occur frequently. If they do, the turbines have a protection mechanism that shuts them down. On this occasion, ten wind farms experienced between three and six ride-though events in 120 seconds.
The five wind farms that remained operational were set to allow a maximum of ten events in that time. One of them experienced six.
Three other wind farms were set to allow five events, but each experienced six. Five wind farms were set to allow only two. AEMO’s chart shows “not applicable” for the pre-set limit of another wind farm. It experienced five events. Most or all of the turbines shut down at these farms.
AEMO didn’t know about this protection feature!
Why not? The AEMO report blames the wind farms for not notifying it when they registered for the NEM. But shouldn’t it have inspected the factory specifications of the equipment?
It appears that all of South Australia’s wind farms operated correctly according to their settings. But no one thought to analyze whether the settings were appropriate.
No one could have anticipated the severity of the weather on that day. Nothing could have prevented service interruptions. But they didn’t necessarily have to be as severe as they were.
The state of technology
Integration of intermittent power generation into the grid has only recently occurred. Grid operators are beginning to learn how to deal with it. Good decision making comes from experience. Experience comes from bad decisions.
Energy storage holds the promise of smoothing out disruptions to the flow of electricity. Neither the technology nor the amount of storage deployed has sufficiently advanced to fulfill that promise in sudden emergencies.
Massive blackouts have occurred worldwide and for generations. In most cases the system that failed used little or no renewable energy. The idea that scaling back on deployment of renewable energy will protect the grid from blackouts is absurd.
Going forward, AEMO data should help everyone involved in generating and distributing energy to improve their operations.
The role of political dysfunction in the South Australia blackout
Both sides of the dispute find information in the official reports that justifies their viewpoint. Both sides overstate their case.
The newspaper articles I read all have dozens of often uncivil comments. People talk past each other and call each other names. They show too little respect or willingness to consider any merit in others’ viewpoints.
We can’t solve our problems if we can’t have honest conversations about them.
Black system South Australia 28 September 2016 / Australian Energy Market Operator. Fourth and final report, March 2017.
Chaotic wind power the cause of South Australia’s infamous blackouts / Michael Owens, StopTheseThings. December 16, 2016.
Experts speak out: to stop South Australian blackouts, we need to encourage renewables / Rae Johnston. Gizmodo. January 23, 2017.
Prime Minister Malcolm Turnbull and ministers were told wind not to blame for South Australia blackout / Mark Kenny, The Sydney Morning Herald. February 13, 2017.
Seven tornadoes hit SA on day of massive blackout: Bureau of Meteorology report / Elizabeth Henson. The Advertiser [Adelaide, South Australia newspaper]. November 14, 2016
Wind farm failure during SA storm worse than thought / Mark Ludlow, Financial Review. October 19, 2016
Downed transmission tower. Source unknown
Wattle Point windfarm, South Australia Public domain from Wikimedia Commons
Tornado. NOAA photo. Public domain
South Australia locator Public domain from Wikimedia Commons
Men arguing. Some rights reserved by o5com (Link to Flickr no longer works)