Overview of the NEM

The National Electricity Market (NEM) operates on one of the world's longest interconnected power systems. It covers around 40,000 km of transmission lines and cables, supplying a population exceeding 23 million.

The NEM is a wholesale market where electricity is traded across five interconnected regions: Queensland (QLD), New South Wales (NSW), Victoria (VIC), South Australia (SA), and Tasmania (TAS). Each region acts as a separate pricing zone, and prices can diverge when the transmission lines (interconnectors) between them become congested.

Simple usage

This package handles the download of data from the NEMWEB Archive and the parsing of the data into a System from PowerSystems.jl. At the moment only a simple zonal network model is available (a nodal model with physical lines is a work-in-progress), which allows to model a simple economic dispatch. By default, the package will create a hidden folder .aem_cache in the home directory, and save the data into parquet files.

julia

using AustralianElectricityMarkets
using TidierDB
using Dates
using PowerSystems
using DataFrames
using Chain
using CairoMakie, AlgebraOfGraphics

db = aem_connect(duckdb());
date_range = Date(2025, 1, 1):Date(2025, 1, 2)

tables = table_requirements(RegionalNetworkConfiguration())
map(tables) do table
    fetch_table_data(table, date_range)
end;

<frozen importlib._bootstrap>:488: Warning: OpenSSL 3's legacy provider failed to load. Legacy algorithms will not be available. If you need those algorithms, check your OpenSSL configuration.
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mCreating cache directory at /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mCreating temp cache directory at /tmp/.nemweb_temp[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for INTERCONNECTOR 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for INTERCONNECTOR 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 206.58it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for INTERCONNECTORCONSTRAINT 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for INTERCONNECTORCONSTRAINT 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 524.48it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for DISPATCHREGIONSUM 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for DISPATCHREGIONSUM 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 217.47it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for DUDETAIL 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for DUDETAIL 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 363.33it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for DUDETAILSUMMARY 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for DUDETAILSUMMARY 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 184.92it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for STATION 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for STATION 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 732.89it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mChecking if data already exists for STATIONOPERATINGSTATUS 2025 / 1[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mData already exists for STATIONOPERATINGSTATUS 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 779.47it/s]
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:37[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mChecking if data already exists for GENUNITS 2025 / 1[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mData already exists for GENUNITS 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 581.90it/s]
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mChecking if data already exists for DUALLOC 2025 / 1[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mData already exists for DUALLOC 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 573.46it/s]
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mChecking if data already exists for BIDDAYOFFER_D 2025 / 1[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mData already exists for BIDDAYOFFER_D 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00, 86.65it/s]
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mSet cache directory to /home/runner/.nemdb_cache[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mSet filesystem to local       [0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mPopulating database with data from 2025-01-01 00:00:00 to 2025-01-01 00:00:00[0m
  0%|          | 0/1 [00:00<?, ?it/s][2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mChecking if data already exists for BIDPEROFFER_D 2025 / 1[0m
[2m2026-03-09 05:22:38[0m [[32m[1minfo     [0m] [1mData already exists for BIDPEROFFER_D 2025 / 1, skipping download. Use force_new=True to overwrite.[0m
100%|██████████| 1/1 [00:00<00:00,  1.34it/s]100%|██████████| 1/1 [00:00<00:00,  1.34it/s]

Once the data is downloaded, a few utility functions allow direct parsing of key quantities, such as a table of all units registered in the NEM, or the region zonal operational demand.

julia

units = read_units(db)

capacity_by_fuel = @chain units begin
    select(:DUID, :REGISTEREDCAPACITY, :CO2E_ENERGY_SOURCE, :REGIONID)
    groupby([:CO2E_ENERGY_SOURCE, :REGIONID])
    combine(:REGISTEREDCAPACITY => (x -> sum(x) / 1000) => :installed_capacity_gw)
    dropmissing
    sort!(:installed_capacity_gw)
    subset!(:installed_capacity_gw => ByRow(>=(0.1))) ## Ignore marginal sources
end

spec = mapping(
    :REGIONID,
    :installed_capacity_gw => "Installed capacity [GW]",
    stack = :CO2E_ENERGY_SOURCE,
    color = :CO2E_ENERGY_SOURCE => "Fuel source"
) * visual(BarPlot, alpha = 0.8)
fig = data(capacity_by_fuel) * spec
draw(
    fig,
    figure = (; title = "Installed capacity in the National Electricity Market by energy source"),
    scales(Color = (; palette = from_continuous(:Paired_12)))
)

Read the demand for each state. In the NEM, this is referred to as Operational Demand, which is the demand met by local scheduled and semi-scheduled generation, plus net imports from other regions. It excludes "behind-the-meter" rooftop PV, which instead appears as a reduction in operational demand.

julia

demand = read_demand(db)

begin
    spec = data(
        subset(demand, :SETTLEMENTDATE => ByRow(x -> (Date(2025, 1, 20) <= x <= Date(2025, 1, 31))))
    )
    spec *= mapping(:SETTLEMENTDATE => "Date", :TOTALDEMAND => "Total Demand [MW]", color = :REGIONID => "State")
    spec *= visual(Lines)
    figure_options = (;
        title = "Regional demand in each Australian state",
        subtitle = "Period of January 20th 2025 to January 31st 2025",
    )
    draw(spec; figure = figure_options)
end

Australia has a fairly high penetration of PV, which at times exceed a state's total demand for electricity (in SA in particular).

julia

begin
    spec = data(
        subset(demand, :SETTLEMENTDATE => ByRow(x -> (Date(2025, 1, 20) <= x <= Date(2025, 1, 31))))
    )
    spec *= mapping(:SETTLEMENTDATE => "Date", :SS_SOLAR_AVAILABILITY => "Total Demand [MW]", color = :REGIONID => "State")
    spec *= visual(Lines)
    figure_options = (;
        title = "Solar generation from semi-scheduled units per state",
        subtitle = "Period of January 20th  2025 to January 31st 2025",
    )
    draw(spec; figure = figure_options)
end

Integration with PowerSystems.jl

The main purpose of this package is to provide the data required for instantiating systems with PowerSystems.jl and leverage the ecosystem of power systems modelling developed by NREL-Sienna.

julia

sys = nem_system(db, RegionalNetworkConfiguration())

Property	Value
System
Name
Description
System Units Base	SYSTEM_BASE
Base Power	100.0
Base Frequency	60.0
Num Components	602

Type	Count
Static Components
ACBus	12
Arc	12
Area	6
AreaInterchange	8
EnergyReservoirStorage	31
HydroDispatch	84
Line	14
PowerLoad	6
RenewableDispatch	222
ThermalStandard	199
TransmissionInterface	8

Users can then interact with the system with all PowerSystems utilities.

julia

thermal = @chain get_components(ThermalGen, sys) |> DataFrame begin
    select!([:name, :fuel, :prime_mover_type, :base_power])
    groupby(:fuel)
    combine(:base_power => sum => :installed_capacity_mw)
end

5×2 DataFrame

Row	fuel	installed_capacity_mw
	ThermalF…	Float64
1	PowerSystems.ThermalFuelsModule.ThermalFuels.NATURAL_GAS = 18	9710.0
2	PowerSystems.ThermalFuelsModule.ThermalFuels.COAL = 1	21371.0
3	PowerSystems.ThermalFuelsModule.ThermalFuels.OTHER_GAS = 19	1329.0
4	PowerSystems.ThermalFuelsModule.ThermalFuels.AG_BYPRODUCT = 21	480.0
5	PowerSystems.ThermalFuelsModule.ThermalFuels.DISTILLATE_FUEL_OIL = 9	841.0

Get information for a specific unit.

julia

gen = get_component(ThermalGen, sys, "JLA02")

ThermalStandard: JLA02:
   name: JLA02
   available: true
   status: true
   bus: ACBus: VIC1_GEN_BUS
   active_power: 0.0
   reactive_power: 0.0
   rating: 0.51
   active_power_limits: (min = 0.0, max = 0.6499999916553497)
   reactive_power_limits: nothing
   ramp_limits: (up = 0.23000000149011612, down = 0.23000000149011612)
   operation_cost: PowerSystems.ThermalGenerationCost composed of variable: InfrastructureSystems.FuelCurve{InfrastructureSystems.LinearCurve}
   base_power: 51.0
   time_limits: (up = 8.0, down = 8.0)
   must_run: false
   prime_mover_type: PowerSystems.PrimeMoversModule.PrimeMovers.CC = 4
   fuel: PowerSystems.ThermalFuelsModule.ThermalFuels.NATURAL_GAS = 18
   services: 0-element Vector{PowerSystems.Service}
   time_at_status: 10000.0
   dynamic_injector: nothing
   ext: Dict{String, Any}("postcode" => "3000", "station_name" => "Jeeralang \"A\" Power Station", "station_id" => "JEERA")
   InfrastructureSystems.SystemUnitsSettings:
      base_value: 100.0
      unit_system: InfrastructureSystems.UnitSystemModule.UnitSystem.SYSTEM_BASE = 0
   has_supplemental_attributes: false
   has_time_series: false

Check the prime mover type.

julia

get_prime_mover_type(gen)

PowerSystems.PrimeMoversModule.PrimeMovers.CC = 4

Check the rating in natural units.

julia

with_units_base(sys, "NATURAL_UNITS") do
    get_rating(gen)
end

51.0

Overview of the NEM ​

Simple usage ​

Integration with PowerSystems.jl ​

Overview of the NEM

Simple usage

Integration with PowerSystems.jl