The changing nature of Australia's electricity generation is still powering the nation adequately but more has to be done to keep the system secure and reliable, one of the major energy regulators warns.
The Australian Energy Market Commission's annual reliability report, released on Tuesday, finds there's enough generation capacity in the system to meet demand in the short and medium term.
While households are using more electrical appliances, demand is declining slightly because of energy-efficiency improvements and the massive growth in rooftop solar.
But the increase in wind and solar power and closure of coal-fired generators is creating problems.
"With more weather-driven generation, and more coal-fired generation leaving, the technical characteristics of the grid are changing," AEMC chief executive Anne Pearson said on releasing the 2016/17 review.
"The power system has to be managed differently in response to the changing generation mix."
Managing the power system - by keeping things like frequency and voltage within technical limits - is becoming more challenging.
Energy market regulators have already taken a series of major steps aimed at addressing these changing reliability and security requirements, and the AEMC also released for feedback on Tuesday another package of measures targeted at addressing the deteriorating frequency performance in the system.
The reliability review noted there were 11 instances during the 2016/17 financial year of the system running outside its "secure zone" - up from seven in the previous year and four the year before that.
But just four of them led to blackouts, including the statewide "system black" in South Australia after tornadoes ripped up power lines in September 2016.
The other incidents involved a fault on a transmission line in Victoria that led to the interconnector between that state and SA shutting down, the failure of thermal power generators in NSW, and faults at a switchyard in SA which almost led to another system black.
There was also one blackout caused by a reliability incident, on an extremely hot February 2017 day in SA when demand was higher than forecast, wind generation lower than predicted and the Pelican Point gas plant was unexpectedly unavailable.
But 97 per cent of all the blackouts for that year were caused by distribution failures - that is, problems with the poles and wires.
