A forecast layer, deliberately separated

The SWIS daily operating record is measured history: minimum demand, rooftop PV, generation mix and evening ramp across retained AEMO WEM observations. The WEM Electricity Statement of Opportunities is a model of the next ten years, testing whether generation, storage and demand-side capacity can satisfy the WEM Planning Criterion over ten future Capacity Years under Low, Expected and High scenarios.

This page uses AEMO's Expected scenario as a reference case. It is not Solar Analytica's forecast, and it is not an investment recommendation. AEMO itself cautions that project delivery, demand, market behaviour and model assumptions may produce materially different actual outcomes. Each forecast number below stays tied to its scenario, information cut and dependency.

The near term improves, then the requirement opens again

AEMO forecasts existing and committed peak capacity at 6,670 MW in 2028-29 against a 6,323 MW Peak Reserve Capacity Target, a 347 MW surplus. That balance depends on committed projects arriving on time and the assumed availability of existing facilities. From 2029-30, the same existing-and-committed series falls below the target as demand grows and thermal generation retires or becomes unavailable.

The end point is not a prediction that 2,161 MW will definitely be missing in 2035-36. It is the gap in one scenario before uncommitted future investment. AEMO identifies 622 MW of anticipated capacity in 2028-29 and 661 MW in 2030-31; if anticipated projects are delivered, the model remains balanced through 2030-31 and the shortfall begins in 2031-32. The schedule therefore moves with the committed-versus-anticipated distinction.

Consumer assets enter the capacity model

The 2026 methodology gives coordinated distributed energy a more explicit role. AEMO forecasts rooftop PV capacity to rise from about 3,100 MW in 2026-27 to about 6,000 MW by 2035-36, while distributed battery capacity rises from about 550 MW to 2,300 MW. Those stocks change both daytime grid demand and the shape of the evening peak.

For 2028-29, AEMO projects 640 MW of installed distributed batteries could be coordinated through Synergy virtual power plants. It applies a 50 per cent availability factor because remote control, customer behaviour and operational performance are still uncertain, and forecasts approximately 200 MW of annual peak-demand reduction. The 200 MW exists in the model, and its first test arrives with the 2026-27 Hot Season.

Longer batteries become a market requirement

Duration is now specified alongside megawatts. AEMO increases the Electric Storage Resource Duration Requirement from six hours in 2027-28 to seven hours in 2028-29 as the peak becomes longer and flatter. The 2028-29 target also includes a 392 MW duration uplift to account for the reduced contribution of shorter-duration batteries across the peak period.

This connects the outlook to Solar Analytica's Revenue Opportunity Lab and TBx Capture Index only at the level of a decision question: duration matters. The WEM capacity mechanism, NEM energy spreads and a household VPP are different commercial structures and should not be collapsed into one revenue assumption.

The surplus is conditional

The 2028-29 forecast surplus is conditional on timely project delivery. The model expects distributed solar and batteries to become system-scale resources, though the VPP contribution carries an explicit availability haircut and a near-term validation task. And the forecast need reopens quickly after 2028-29, with transmission, storage duration and flexible capacity determining whether nominal megawatts can meet the shape and location of demand.

On the ESOO's own accounting, the schedule comes down to one question: whether anticipated capacity is delivered. Delivered, the gap opens in 2031-32; not delivered, 2029-30. Use the SWIS Rooftop Solar Atlas for the current local installed base, the operating record for realised system conditions, and this brief for AEMO's planning case. The desk will mark this outlook against the operating record as each Capacity Year closes, starting with the 2026-27 Hot Season VPP result.