AEMO further relaxes limits on wind generation in South Australia | RenewEconomy

AEMO further relaxes limits on wind generation in South Australia

AEMO relaxes limits on wind generation in South Australia, offering a plethora of new combinations that highlight both the complexity and growing confidence in shift to renewables.


The Australian Energy Market Operator has further relaxed limits on wind generation in South Australia, offering a plethora of new combinations and algorithms that effectively allows up to 1460MW of wind generation without intervention in the market.

AEMO came down heavily on the market in late 2017, effectively capping the amount of wind generation allowed at any one time in the state to 1200MW – unless there was sufficient “synchronous” generation (gas and diesel plants) online to guarantee system security.

Those rules were relaxed to 1295MW in late 2017, and in an unheralded announcement in late December, further relaxed the limits to allow up to 1460MW, depending on the nature of the synchronous generators that are operating at the time.

In some exceptional circumstances, up to 1870MW of wind generation can be allowed, which is actually more than the currently committed capacity of 1809MW.

The new guide presents more than 50 different configurations that the control room can use to decide how much wind can be allowed in the state without either putting in a constraint, or calling on more gas and diesel generators to facilitate more wind generation.

The updated guidelines highlight the growing complexity of the market, and also the growing confidence that the market operator has in allowing more wind and solar into the system.

And it also makes a nonsense of claims from the likes of coal lobbyist Trevor St Baker – who is a part owner of the Vales Point coal generator in NSW, and proposes to build new coal plants under the Coalition’s controversial underwriting plan – that wind and solar should be limited to 50 per cent of output in any state grid at any one time.

AEMO makes the point that the limits on wind do not apply to either of the two grid scale battery storage units installed in the state – at Hornsdale (the Tesla big battery) and Dalrymple North.

Nor does it apply to the state’s big solar farms, the huge Bungala solar farm near Port Augusta, which has the first 120MW stage fully opertational, and the second 120MW stage completed but still undergoing commissioning,

AEMO is keen to reduce the number of directions it needs to impose in the market, and the amount of wind that is constrained.
In its latest Quarterly Energy Dynamics report, the amount of wind constrained in the fourth quarter fell to just four per cent (from 10 per cent in the previous quarter) and the number of market interventions also reduced

It said directions were in place for 13 per cent of the time in South Australia during the latest quarter compared to 29 per cent during the third quarter.

However, the fourth quarter also marked the first major set of directions in Victoria to maintain system security. AEMO says it issued four directions in total to units to ensure system strength and control voltage levels in Victoria during November, with units in the region directed for 1.9 per cent of the time over the quarter.

The security issues tended to occur during times of low demand and low levels of brown coal-fired generation in the region (see graph above to the right).

AEMO also made its first market intervention in the WA market, this time in response to anticipated fluctuations in rooftop solar output, and as the amount of rooftop solar (now more than 1GW) continues to lower minimum demand. We will have more on that landmark event in the next couple of days.

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