The Australian Energy Market Commission (AEMC) this week released reforms to maintain power supplies and guard against blackouts as power from renewable sources enter the grid.
Releasing the report, AEMC Chairman John Pierce also called for submissions on proposed rules to stabilise the grid in relation to frequency management.
Frequency management will become more critical to maintaining a stable electricity grid as more renewables feed into it.
Synchronous and asynchronous electricity generators
That’s because Australia’s AC current reverses its direction 50 times per second, resulting in our 50 Hz electricity supply. Coal-fired generator turbines are synced to this 50 times per second rotation – hence they are ‘synchronous’ generators.
The spinning turbines’ inertia, or tendency to keep revolving, stops the power grid from blacking out if a coal-fired generator fails. That’s because their output doesn’t go from ‘on’ to ‘off’ in a split second. The massive turbines keep rotating for a while, even after the generator is technically ‘off’.
The problem with solar and wind is they are ‘asynchronous’. This means they do not generate power by revolving at the grid frequency of 50 Hz. Therefore, they have no protective inertia. If a solar panel stops working because of a storm, it immediately stops feeding electricity into the grid.
However, there are ways to use clever technology to produce ‘synthetic inertia’ so that if there is a sag in grid frequency, wind and solar can fill that gap. These include using battery storage as a stand-by power source.
Electricity market is ‘a complex interconnected system’
Mr Pierce said the reforms address risks to energy security as asynchronous generators like wind and solar come in, and synchronous generators like coal retire.
“The [National Electricity Market] today is a complex interconnected system of renewable and non-renewable energy generation,” Mr Pierce said.
“We are focused on the power system’s evolution. Our reform package is looking at ways to stabilise the system as the generation mix changes, and new technology generators connect.”
Mr Pierce said the proposed reforms to manage frequency and strengthen the system will involve Australian Energy Market Operator and the networks working together.
