A course and a catalog

NEM constraints, from the wires up

Every five minutes AEMO's dispatch engine runs the National Electricity Market as one big optimisation. Constraints are the rules it must obey. This course builds them up from first principles, checks your understanding as you go, and hands you a catalog of the data behind them.

How to use it

Read the chapters in order; each one leans on the last. Between sections you will meet short question blocks. Answer them, press Check, and read the explanation whether you were right or wrong: the explanations carry the point of the section. Your answers stay in this browser so you can come back later. Nothing is locked; skip ahead whenever you like.

Numbers marked as measured come from archived NEMDE solutions for June to early August 2026, read from a database this course's author kept while running a constraint simulator. They are observations from one winter, not permanent facts about the grid.

The course

    The catalog

    MMS data modelAll 571 tables of AEMO's Electricity Data Model v5.7, every column, with practical notes on the ones that matter for constraints. Units and stationsEvery registered unit, station and participant, with the constraints that reference each unit. Grid reference sheetsRegions, interconnectors, FCAS services, naming grammar, market time, thresholds. NEMWeb feedsWhich report carries which table, how often, how late, and the traps. Glossary and gotchasEvery term used in the course and the hard-won data gotchas behind them.

    Further reading

    • AEMO, Constraint Formulation Guidelines and Constraint Naming Guidelines (the official grammar this course paraphrases).
    • AEMO, Network and FCAS Constraints in the NEM training deck (2024).
    • AEMO, MMS Electricity Data Model Report v5.7 (the source of the table catalog).
    • AEMO's Constraint Implementation Guidelines and the annual Transmission Constraint Report (how congestion is costed and ranked).