Moorabool wind farm. Photo: Goldwind
Australia’s National Electricity Market (NEM) has experienced another remarkable sequence of renewable energy records, highlighting both the growing contribution of rooftop solar and the changing opportunities for making use of available wind and solar generation.
Over five days, from 7 to 11 October 2026, new rooftop photovoltaic (PV) output records were established in South Australia, Victoria, New South Wales and across the NEM, Australia’s main grid.
The sequence culminated on Sunday 11 October, when NEM rooftop PV output reached 17,488 MW at 12:00 AEST, surpassing the previous record of 16,993 MW set on 20 September 2026.
That represents an increase of 495 MW (+2.91%) in just three weeks. Compared with the corresponding historical benchmark of 15,100 MW on 4 October 2025, rooftop PV output was 2,388 MW (+15.81%) higher.
NSW had already established a new record of 6,346 MW on Friday 9 October, following new highs in South Australia and Victoria earlier that week.
Yet alongside this growing solar contribution came another set of records: substantial renewable energy curtailment, prolonged negative wholesale electricity prices and marked differences in how much surplus energy could be absorbed by flexible electricity demand.
On Sunday 11 October, Victoria recorded an instantaneous renewable curtailment peak of 5,709 MW at 12:15 AEST, just 15 minutes after the NEM rooftop PV record.
This exceeded Victoria’s previous record of 5,279 MW, set on 20 September 2026, by 430 MW (+8.15%). Against the historical comparison of 4,798 MW on 10 October 2025, the increase was 911 MW (+18.98%).
Other records included NEM wind curtailment of 6,425 MW, Victoria wind curtailment of 4,229 MW, Victoria solar curtailment of 1,554 MW and South Australia wind curtailment of 1,910 MW. These peaks occurred at different five-minute intervals and should not be interpreted as simultaneous. Together, however, they illustrate the scale of available renewable generation that was not dispatched during the day.
The GPE NEMLog Energy Source chart illustrates the midday curtailment profile through the pink Dolphin Curve, showing how much available renewable generation was not dispatched. The shape provides a useful visual counterpart to the familiar Duck Curve, drawing attention to renewable energy availability beyond dispatched generation. The concept is explored further in the NEMLog explanation and RenewEconomy’s Dolphin Curve feature.
Across the NEM, renewable curtailment totalled approximately 82.3 GWh on 11 October, ranking as the fifth-highest daily total in GPE NEMLog’s historical series extending back to 2018. Victoria accounted for approximately 48.8 GWh, followed by South Australia at 17.9 GWh. Together, the two regions contributed about 81% of the NEM total, illustrating how concentrated the day’s curtailment was geographically.
An estimated 72.4 GWh, or 87.9% of the day’s curtailed renewable energy, occurred during negative-price intervals. South Australia experienced prolonged negative wholesale prices, reaching -$414.98/MWh at 12:10 AEST. At that interval, regional demand was just 301 MW, while AEMO network demand was -74 MW. Grid-scale batteries were consuming 338 MW, renewable curtailment was 2,139 MW and net exports were only 27 MW. Victoria’s wholesale price simultaneously reached -$365.23/MWh.
The Victorian historical summary provides an important distinction between instantaneous peaks and sustained daily conditions. Sunday’s 5,709 MW curtailment peak ranked first historically, while its daily mean of approximately 2,037 MW ranked third. The NEM-wide daily total was exceptional, but it did not surpass the previous daily record.
GPE NEMLog’s absorption fingerprint provides another perspective on Sunday’s conditions by examining observable flexible electricity consumption alongside renewable curtailment. Across the day, flexible load totalled 25.1 GWh, comprising approximately 19.2 GWh of grid-scale battery charging and 5.9 GWh of pumping consumption.
There were substantial regional differences. Flexible-load absorption accounted for approximately 51% of combined observable flexible load and curtailment in NSW and 59% in Queensland. The corresponding figures were only 12% in South Australia and 10% in Victoria, indicating quite different balances between the flexible demand observed and the renewable energy curtailed.
These figures should not be interpreted as the proportion of curtailment that could automatically have been recovered through additional storage. The timing and location of renewable availability, network access, operating constraints and the economics of storage all influence what can realistically be absorbed. The comparison is useful for understanding regional conditions, rather than establishing an optimal level of flexibility.
The scale of Sunday’s curtailment raises an important question: how much renewable energy should the NEM seek to capture, and when does allowing some to go unused make economic sense? It is tempting to regard every curtailed megawatt-hour as a missed opportunity, but that does not necessarily follow from the data.
As explored in an earlier GPE NEMLog analysis, How Much Curtailment Is Enough?, curtailment is not necessarily evidence of market failure or inadequate investment. Some curtailment can be an economically rational outcome when the additional cost of storage, transmission or flexible demand exceeds the value of recovering the energy. The relevant question is therefore not simply how much energy has been curtailed, but what opportunities exist to use more of it productively and at an economically justifiable cost.
This also means that high curtailment and increasing flexibility are not necessarily contradictory observations. Renewable availability can grow faster than the capacity or economic incentive to absorb it, even while storage and flexible demand continue expanding. Understanding that relationship requires more than a single record or a daily total.
Rooftop PV is increasingly shaping conditions across the NEM by reducing demand supplied through the operational grid. On Sun 11 Oct 2026, combined utility-scale solar and rooftop PV output also established a new record share of NEM consumption, reaching 72.29%, compared with 70.80% on 12 Sep 2026.
The GPE NEMLog Energy Source dashboard illustrates the changing generation mix and solar contribution throughout the day. This growing consumer-side contribution is changing the conditions experienced by grid-connected generators and other market participants.
However, another dimension remains less visible. While GPE NEMLog provides estimates of rooftop PV output and tracks grid-scale renewable curtailment, it cannot separately quantify rooftop solar energy curtailed behind the meter through export limits, inverter controls or other mechanisms.
Similarly, the growing contribution of household and consumer batteries is not fully observable in the same way as grid-scale battery charging and discharging.
This visibility gap matters as consumer energy resources become an increasingly important influence on operational demand and wholesale market conditions.
Better information would help distinguish changing patterns of consumption, generation, storage and curtailment, while recognising that consumer-owned assets serve household and business priorities as well as potential wider system needs.
The October records are not simply a story about renewable generation growing faster than the electricity system can accommodate. They reveal a changing set of opportunities and choices. Some available renewable energy can be moved through transmission, stored for later use or consumed by flexible demand, while some may be more economically left unused.
At the same time, the rapid growth of rooftop solar and consumer batteries is changing where electricity is produced, how consumers respond and how much of that activity is visible to the wider market.
These developments raise questions that cannot be answered by curtailment figures alone. How effectively is the NEM responding to periods of renewable abundance? Which additional opportunities for flexibility are genuinely valuable? And how do we recognise the choices and priorities of consumers whose assets may increasingly influence the wider system?
Eliminating curtailment is not necessarily the objective. The more useful question may be whether the NEM is becoming better at recognising and making use of the opportunities renewable abundance creates, while understanding when allowing some energy to go unused is the sensible outcome.
Source: GPE NEMLog analysis of NEM generation, rooftop PV, dispatch, pricing, renewable curtailment and flexible-load data. All times AEST. Curtailment values represent GPE NEMLog estimates of available renewable output not dispatched.
Geoff Eldridge is a National Electricity Market (NEM) and Energy Transition Observer at Global Power Energy.
In "Chart of the day"
In "Chart of the day"
In "Chart of the day"
Geoff Eldridge is a National Electricity Market (NEM) and Energy Transition Observer at Global Power Energy.
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