Live estimates of solar and wind curtailment across the NEM — comparing weather-derived expected output against actual dispatch to quantify how much renewable generation is being constrained or curtailed.
Curtailment occurs when renewable generators produce less electricity than they could based on available wind or solar resources. This can happen voluntarily — when generators reduce output in response to negative prices — or involuntarily, when AEMO or network operators constrain output to maintain system security.
In Australia's NEM, curtailment is driven by several factors: network congestion (particularly in renewable-rich zones like north Queensland and western Victoria), minimum system load requirements, frequency control limits, and interconnector capacity constraints. As renewable penetration increases, curtailment is becoming a growing concern for project economics.
Network constraints are the most common cause. When renewable output exceeds the transmission capacity of a particular corridor, AEMO constrains generators behind the binding constraint. This is particularly common in regions like South Australia and north Queensland where significant generation capacity has been built ahead of transmission upgrades.
Negative pricing provides an economic signal for curtailment. When wholesale prices drop below zero — often during midday solar peaks — generators without contracted offtake may choose to reduce output rather than pay to generate. See our live electricity prices to track negative price events across regions.
System security requirements can also trigger curtailment. AEMO must maintain minimum levels of synchronous generation for inertia and system strength, which can require constraining non-synchronous renewables during periods of very high renewable penetration. Check the generation mix to see current renewable penetration levels.
Curtailment directly affects generator revenue and project returns. For renewable developers evaluating new projects, understanding regional curtailment patterns is essential for accurate revenue modelling. Combined with Marginal Loss Factors, curtailment risk can significantly reduce effective revenue per MWh below the headline spot price.
For PPA counterparties, curtailment affects the volume and timing of contracted generation. Buyers should understand how curtailment patterns in their contracted generator's region might affect delivered volumes. See our PPA guide for more on contract risk factors.
gridIQ estimates curtailment by comparing weather-derived expected output (using registered capacity and current weather conditions) against actual dispatch data from AEMO. These are estimates — actual curtailment involves factors like local network constraints and commercial arrangements not visible in public data.
Monitor real-time curtailment estimates, binding constraints, negative pricing events, and renewable penetration — all in one platform. Ask Watt AI for instant analysis.
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