{
  "slug": "aemo-rooftop-pv-forecast-accuracy-2026",
  "title": "The Rooftop Solar Forecast That Swung Both Ways",
  "url": "https://solaranalytica.com/aemo-rooftop-pv-forecast-accuracy-2026",
  "summary": "AEMO's own Forecast Accuracy Reports grade its Central forecast of installed rooftop PV at -2.2%, -6.5% and then +5.5% across three consecutive ESOOs, with the last over-forecast in every NEM region. AEMO attributes both directions to one assumption, the growth in average system size. The actuals are provisional and the horizon is under a year.",
  "license": "Free to use with attribution to Solar Analytica (solaranalytica.com). Underlying figures are named to their public sources below.",
  "csv": "https://solaranalytica.com/reports/aemo-rooftop-pv-forecast-accuracy-2026/data.csv",
  "datePublished": "2026-09-28",
  "lastReviewed": "2026-09-24",
  "sources": [
    {
      "title": "AEMO: Forecast Accuracy Report, December 2023 (review of the 2022 ESOO), Table 5",
      "url": "https://www.aemo.com.au/-/media/files/electricity/nem/planning_and_forecasting/accuracy-report/2023-forecast-accuracy-report.pdf"
    },
    {
      "title": "AEMO: Forecast Accuracy Report, December 2024 (review of the 2023 ESOO), Table 5 and section 3.3",
      "url": "https://www.aemo.com.au/-/media/files/electricity/nem/planning_and_forecasting/accuracy-report/2024-forecast-accuracy-report.pdf?rev=ef5f0bd639e941c998a868b299df6376&sc_lang=en"
    },
    {
      "title": "AEMO: Forecast Accuracy Report, December 2025 (review of the 2024 ESOO), Table 5",
      "url": "https://www.aemo.com.au/-/media/files/electricity/nem/planning_and_forecasting/accuracy-report/2025-forecast-accuracy-report.pdf"
    },
    {
      "title": "AEMO: 2025 Electricity Statement of Opportunities, August 2025",
      "url": "https://www.aemo.com.au/-/media/files/electricity/nem/planning_and_forecasting/nem_esoo/2025/2025-electricity-statement-of-opportunities.pdf"
    }
  ],
  "figures": [
    {
      "id": "nem-rooftop-pv-forecast-error",
      "title": "Rooftop PV Central forecast error, NEM, by ESOO vintage",
      "unit": "% (forecast minus estimated actual, over estimated actual)",
      "caption": "Forecast minus estimated actual installed rooftop PV capacity at 30 June, over the estimated actual, NEM total, Central scenario. Negative is an under-forecast. AEMO Forecast Accuracy Report, Table 5, 2023, 2024 and 2025 editions. The estimated actuals are provisional: installers have up to a year to register a system.",
      "provenance": {
        "dataSource": "AEMO Forecast Accuracy Report, Table 5, 2023 to 2025 editions",
        "dataType": "Publisher-reported forecast error against estimated actuals",
        "scope": "NEM total, Central scenario, installed rooftop PV at 30 June"
      },
      "series": [
        {
          "label": "2022 ESOO",
          "value": -2.2
        },
        {
          "label": "2023 ESOO",
          "value": -6.5
        },
        {
          "label": "2024 ESOO",
          "value": 5.5
        }
      ]
    }
  ]
}