South Australia has the most wind and solar, so why is not worrying about a vulnerable grid?
South Australia has the highest wind and solar share – an average of around 72% over the last 12 months – more than any other state in Australia, and higher than any other gigawatt scale grid in the world.
Renewable energy critics assume that this means South Australia’s grid must be weak and unreliable.
But that is simply not true, and a new report from AEMO on “system strength” underlines why this is so.
AEMO’s 2024 System Strength Report finds that there are potential shortfalls in system strength in all of the states that make up the country’s main grid. The one exception is South Australia.
South Australia closed the last of its coal fired generators in 2016, and despite having a number of gas generators these are largely “peaking plants” that operate rarely.
AEMO and the local network owners have installed four synchronous condensers – spinning machines that do not burn fuel – and which have addressed the issue.
In time, battery storage may also be able to provide that service with their advanced “grid forming” inverters.
Other states, however, are still grappling with the accelerating pace of the energy transition.
The NSW government decision to keep the Eraring coal generator for another two years has effectively deferred its emerging system strength shortfall to 2027.
The main transmission company in the state is Transgrid, and it is currently assessing options to fill that shortfall – likely a mix of syncons and big batteries.
Ironically, the decision to keep Eraring open has caused problems for Queensland because coal plants there will operate less often.
Victoria is also forecast to have a system strength shortfall in 2025/26, largely the result of the expiry of existing contracts.
Even Tasmania, which generates most of its power from hydro, faces multiple shortfalls at all four its network nodes, and the local transmission company is also working to provide solutions.
But the work has already been done in South Australia – underlying why it is now regarded as one of the most secure and reliable grids in the country.