Australian Solar Energy Forecasting System
Background
In 2014, AEMO established the Australian Solar Energy Forecasting System (ASEFS) to provide forecasts of solar energy generation, improving the accuracy of the National Electricity Market (NEM) forecasting processes.
Overview
ASEFS is designed to produce solar generation forecasts for large solar power stations and small-scale distributed photovoltaic (PV) systems, covering forecasting timeframes from 5 minutes to 7 days.
The system has been delivered in two phases:
- ASEFS phase 1 involves the production of solar generation forecasts for significant solar farms. Significant solar farms include any solar farms greater than or equal to 30 megawatts (MW) registered capacity, and any solar farms that AEMO is required to model in network constraints for power system security reasons. Phase 1 commenced operation on 30 May 2014.
- ASEFS phase 2 involves the production of solar generation forecasts for small-scale distributed PV systems, defined as less than 100 kilowatt (kW) system capacity. Phase 2 commenced operation on 30 March 2016.
-
ASEFS phase 1
ASEFS phase 1 (ASEFS1) produces solar generation forecasts using a combination of statistical methods and Numerical Weather Prediction-based models. It uses the following inputs to produce solar generation forecasts for large solar power stations:
- Real time Supervisory Control and Data Acquisition (SCADA) measurements from the solar power station.
- Numerical Weather Prediction data from multiple weather data providers.
- Standing data from the solar power station as defined in the ASEFS Energy Conversion Model.
- Additional information provided by the solar power station, including inverters under maintenance and upper MW limit on the solar farm.
- Imagery from Himawari-8 satellite
AESFS1 produces solar generation forecasts for all NEM forecasting timeframes as follows:
- Dispatch (five minutes ahead).
- 5 Minute Pre-dispatch (five minute resolution, one hour ahead).
- Pre-dispatch (30 minute resolution, up to 40 hours ahead).
- ST PASA (30 minute resolution, seven days ahead).
The ASEFS Energy Conversion Model and relevant guides can be found here.
-
ASEFS phase 2
ASEFS phase 2 uses a combination of statistical and physical methods and Numerical Weather Prediction-based models. It uses the following inputs to produce aggregated regional solar generation forecasts for small-scale PV systems:
- Numerical Weather Prediction data from multiple weather data providers.
- Output measurements from selected household rooftop PV systems from PvOutput.org and Solar Analytics.
- Static data from selected systems from PvOutput.org and Solar Analytics, such as inverter size and model.
- Aggregate kilowatt capacity by installed postcode for small-scale solar systems as recorded by the Clean Energy Regulator.
- Imagery from Himawari-8 satellite.
ASEFS2 produces solar generation forecasts for the following NEM forecasting timeframes:
- Pre-dispatch (30 minute resolution, up to 40 hours ahead).
- ST PASA (30 minute resolution, seven days ahead).
Forecasts and actuals for aggregated small-scale PV systems as produced by ASEFS2 can be found here. There are several types of estimated actuals produced by ASEFS2, described in the table below.
Type of Estimated Actuals
Description
Frequency
Measured Actuals
Up-scaled generation estimates using PVOutput.org and Solar Analytics sample meters, and CER installed capacity data.
Every 30 minutes, delayed by 30 minutes.
Satellite Actuals
Up-scaled generation estimates using imagery from Himawari-8 satellite, and CER installed capacity data.
Every 30 minutes, delayed by 30 minutes.
Daily Actuals
Up-scaled generation estimates using a larger number of PVOutput.org and Solar Analytics sample meters, and CER installed capacity data. In October 2019, the Daily Actuals were retired.
Midnight on the day following.