The South Australian power grid is operated by ElectraNet and connected to the National Electricity Market via two interconnectors to Victoria.
The preliminary report from the Australian Energy Market Operator (AEMO) identified that problems started 90 seconds before the eventual failure.
[13] AEMO identified software settings in the wind farms that prevented repeated restarts once voltage or frequency events occurred too often.
The rather larger group of turbines that could not accept this many repeated ride-throughs dropped out, instigating the overload and shutdown of the interconnector, and hence the electricity supply.
The companies AGL Energy, Neoen, Pacific Hydro and Tilt Renewables operated several of the large wind farms that tripped during the incident including Hallett,[14] Hornsdale, Clements Gap and Snowtown.
The Mintaro Emergency Diesel Generator had suffered storm damage, including a cloud-to-ground lightning strike in very close proximity, but would not have been useful anyway due to its location in the network and downed transmission lines.
[19] The Flinders Medical Centre, a major hospital in Adelaide's southern suburbs, was affected when the fuel pump for the diesel-powered back-up generator failed after operating for about an hour.
"[6] South Australian senator Nick Xenophon said he supported renewable energy but that the state's approach relied too much on wind.
[6] Former Opposition Leader Bill Shorten accused the Coalition of "playing politics with what is a natural disaster" and that there was no link between the storm damage and the state's renewable energy target.
[23] The Grattan Institute's Tony Wood was reported as saying "If you've got a wind farm or a coal-fired power station at the end of a transmission line, and that system either is taken out by a storm or is forced to shut down to protect itself from a storm, it doesn't matter what the energy source is" while Clean Energy Council's Tom Butler said the weather event "created a fault in the system which has caused the generation to trip offline" and that "the Snowtown wind farm, north of Adelaide, was actually helping to prop up the state's power supply ahead of gas power stations as the network was gradually brought back online.
"[25] Victorian Premier Daniel Andrews told ABC radio that Turnbull had conflated two issues, that "the poles and wires had blown over".
[26] Following the power outages, the same storm resulted in major flooding, which was dubbed "unrelenting" by South Australia Services Minister Peter Malinauskas.
Further widespread blackouts occurred beginning late on Tuesday 27 December 2016, with areas losing power for upwards of twelve hours following severe storms causing damage to over 300 powerlines in the electricity distribution network.
[28] A total of 155,000 properties lost power at the peak of the storms, requiring over 1200 repair jobs resulting from over 350 powerlines being damaged.
[29] As of 7.30pm on Thursday 29 December, there were more than 11,500 households still without power across the state, some for up to forty-six hours, in regions including the Adelaide Hills, Mid-North, Flinders Ranges, and Murraylands.