Forecasts of intermittent generation are critical to maintaining both power system security and an efficient market.

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 2 years.

The system has been delivered in two phases:

• ASEFS phase 1 involves the production of solar generation forecasts for large solar power stations, defined as greater than or equal to 30 megawatts (MW) registered capacity. 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 Solar Energy Conversion Model.
• Additional information provided by the solar power station, including inverters under maintenance and upper MW limit on the solar farm.

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).
• MT PASA (daily resolution, two years ahead).

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.
• Static data from selected systems from PvOutput.org, such as inverter size and model.
• Aggregate kilowatt capacity by installed postcode for small-scale solar systems as recorded by the Clean Energy Regulator.

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).

Further information and useful links

ASEFS data is available on a voluntary basis to public researchers undertaking solar-related research projects. Further information relating to the terms and conditions of the use of this data can be found here.

• Guide to Intermittent Generation

Link to the Solar Energy Conversion Model.

Link to the Guidance document.

Link to the Clean Energy Regulator small-scale solar system installation by postcode data.

Link to the forecasts and actuals for small-scale PV systems as produced by ASEFS2.

Link to the Short Term Projected Assessment of System Adequacy (ST PASA) process description.

Link to the Medium Term Projected Assessment of System Adequacy (MT PASA) process description.

Australian Wind Energy Forecasting System

Background

The Australian Wind Energy Forecasting System (AWEFS) was established in response to the growth in intermittent generation in the NEM, and the increasing impact this growth was having on NEM forecasting processes. The system aims to provide better forecasts that will drive improved efficiency of overall NEM dispatch and pricing, and permit better network stability and security management.

The implementation project had two broad objectives:

• Facilitating the operation of the market through more accurate wind generation forecasts.
• Facilitating research to improve the quality and dimension of the forecast over time to accommodate other renewable types such as solar.

AWEFS Operation

AEMO hosts the system and maintains its interface to the existing market systems to give data access to the market and to individual wind farms. Data access may also be given to researchers who have signed a sub-licensing agreement and appropriate confidentiality arrangements.

AWEFS produces forecasts from the following inputs:

• Real time SCADA measurements from the wind farms.
• Numerical Weather Predictions from weather forecasters from around the world.
• Standing data from the wind farms.
• Availability information provided by the wind farms, that includes turbines under maintenance and upper MW limit on the wind farm.

The system will produce wind generation forecasts for all NEM wind farms (>= 30MW) 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).
• MT PASA (daily resolution, two years ahead).

Further information

A document providing a high-level overview of the AWEFS design, detailing the inputs, outputs and their usage is provided here. This document also provides information about the linkage between wind generator SCADA, AWEFS, and NEM Dispatch Engine (NEMDE), and how NEMDE generates dispatch instructions (dispatch level and semi-dispatch cap) for semi-scheduled generators using AWEFS forecasts.

• Guide to Intermittent Generation

Link to the Wind Energy Conversion Model.

Link to the Guidance document.