Delays to NEM connections and accurate forecasts

AEMO is currently consulting on its methodology for reliability forecasting in the NEM, and among their proposed changes is an adjustment to the inclusion of projected new capacity. The existing assumptions are being examined due to two factors;

  1. Most new connections in the NEM assume that the time taken to progress from ‘Committed’ status to being fully in service would take on average 150 days, while the observed actual time was 576 days. This discrepancy of 426 days means forecasts like the ESOO significantly over-forecast capacity in the short term.[1]
  2. The ESOO does not include projects further behind in the development cycle as their connection is not certain as far as the existing criteria go. However, it is rare for these projects to not eventually make it to market, resulting in a long-term under-forecast of capacity.

To compensate for this, AEMO has proposed applying the following:

  • A 6-month delay to all projects that have been granted ‘Committed’ status and have not met their first commissioning hold point.
  • Including projects with ‘Anticipated’ status, while also applying a 12-month delay to the project’s full commercial use dates supplied by the participants.

In Figure 1, the capacity in the NEM (including the closure of Liddell in the imminent future) is compared with the forecast capacities from the last 4 major annual ESOO releases. The changes to ‘Anticipated’ timing aren’t significantly relevant in this timeframe, but the delays to ‘Committed’ units can be seen in the dotted lines. As highlighted in the chart, each dotted line, which has been adjusted for AEMO’s proposed methodology, is closer to the actual NEM capacity line than the original.


Reflecting on these changes and comparing them with the actual capacity that has been observed in the NEM over the last 4 years, this change appears to be a step towards closer alignment between forecasts and reality. This means that reports like the ESOO provide more value to participants, more accurately showing the risks to reliability and the opportunities for new storage and generation assets.

Delays during the commissioning process are a known issue, and reforms like the Connections Reform Initiative are being implemented to help assets connect to the NEM, however for developers looking to connect, there is still uncertainty. This is where Cornwall Insight Australia can help, from providing accurate forecasts of potential revenues, understanding and communicating the content of reports that market bodies produce, bespoke models that can take significant infrastructure delays into account, and helping understand the connections process in the Australian energy markets.

Have you recently connected to the NEM or are you seeking to? Please tell us about your experiences! And if you have any questions, please feel free to reach out and we can discuss how Cornwall Insights can help you, contact

To keep reading, please log in to your account or sign up for free

Alternatively, please sign up to receive free market insight online and direct to your inbox

Related thinking

Energy storage and flexibility

Navigating the Changing Landscape of Balancing Services Pricing Developments

From an energy market perspective, 2022 was an especially interesting year as geopolitical events pushed Europe’s energy sector out of the status-quo and into uncertain and uncharted territory. While most of the attention remained focused on developments within the wholesale sphere, interesting developments arose within the balancing services space too....

Power and gas networks

Will we run out of gas this winter?

In unfavourable conditions, gas shortfalls on peak days this winter are a distinct possibility highlighted by AEMO’s 2023 Gas Statement of Opportunities (GSOO). The GSOO is released yearly and provides a forecast of the adequacy of east coast gas supplies based on demand forecasts. The GSOO can highlight to the...

Business supply and services

Average gas and power prices for SMEs declined sharply in February

From late 2021, small and medium enterprises (SMEs) looking to secure a fixed energy contract would have seen steep increases in their energy bills, driven primarily by price volatility in the wholesale energy markets. In this week’s 'Chart of the week', we discuss the changes in prices for SMEs up...

Energy storage and flexibility

Turning Japanese: Typical power price spreads in Japan

Cornwall Insight has been supporting customers in the Japanese market for some time now. This Chart of the week explores the daily spreads seen in recent quarters and why a number of international players are turning to Japan. The Japanese market has experienced substantial volatility in recent quarters. The island...

E-mobility and low carbon

Taking charge: are they ready? Local authority charging infrastructure plans

Electric vehicle (EV) uptake and public charge point installs have increased rapidly over the last few years, but to support the next wave of EV drivers, the public charging network needs to be improved. Government has outlined the leading role it expects from local authorities (LAs) in planning and delivering...

Commercial and market outlook

Prices soar in the west

For the first time in the history of the Western Australian Wholesale Electricity Market (WEM), the balancing price reached the maximum price limit of $1,018/MWh between 5:30pm and 7:30pm on Tuesday, 29 November 2022. This came one month after the state-owned Muja C Unit 5 coal power station was closed....

Energy storage and flexibility

Out with the old, in with the new: T-4 Capacity Market clears at record price

On 21 February, the T-4 Capacity Market auction for Delivery Year 2026-27 cleared at a record high price of £63.00/kW/year, procuring 43,000.955MW of capacity. In this week’s 'Chart of the week', we explore the key takeaways from the auction.

Energy storage and flexibility

A pebble in the water makes a ripple effect…

At demand levels averaging only ~200-700MW, FCAS markets are dwarfed by the ~20,000MW energy demand in the NEM. Nonetheless, with 8 different markets to participate in, the potential value that participating in FCAS can add to a participant's revenue should not be underestimated. In this Chart of the week, we...