How to Choose NEM12 vs NEM13 Meter Data

Interval or accumulation: which meter data format your DNSP or electricity retailer sends

Last Updated: 2026-08-05

Key Takeaways

NEM12 vs NEM13 is a question about your meter, not a menu choice — you request smart meter data and receive the format your meter produces.
NEM12 is interval meter data from a current smart meter, and NEM13 is accumulation meter data from an older legacy meter.
Interval-data analysis tools require NEM12, because one accumulated total cannot show energy use by time of day.
Your DNSP and your electricity retailer must supply the correct meter data format for your NMI and meter, because AEMO rules require it.
Portal labels are menu names, and they can differ between networks.
A detailed report of usage patterns, solar export windows, or time-of-use costs needs NEM12 CSV smart meter data, not a NEM13 total.
NEM13 is legacy technology: as of 2026, the Australian smart meter rollout targets full coverage by 2030.

NEM12 vs NEM13: Interval Data or Accumulation Data?

The meter on your wall decides the NEM12 vs NEM13 question, not a menu choice. NEM12 carries interval meter data. NEM13 carries accumulation meter data.

What Interval Meter Data (NEM12) Records

NEM12 is the interval format in the Meter Data File Format (MDFF) specification from the Australian Energy Market Operator (AEMO). A smart meter records energy in short, repeating intervals.

30-minute intervals: the most common resolution — 48 readings per register per day.
15-minute intervals: 96 readings per register per day, where the meter is configured for it.
5-minute intervals: 288 readings per register per day, the finest resolution NEM12 CSV carries.
Separate registers: import and export stay apart — E1 is a mains grid import register, and B1 is always solar export.
Energy per interval: each reading states the kWh figure for that slice of the day.

What Accumulation Meter Data (NEM13) Records

NEM13 is the accumulation format in the same AEMO specification. It holds one cumulative total for the period between two manual meter reads.

One total per read period: a single number, in place of tens of thousands of interval readings.
Manual reads: a meter reader visits the site, often only a few times each year.
No times inside the period: the file cannot state when the site used the energy.

An accumulation total states how much energy passed through the meter since the last read. It does not state when. For that reason a NEM13 file cannot drive any time-of-day analysis.

Which Meter Data Format Does Your Meter Produce?

Your hardware decides this. One rule of thumb covers almost every connection.

A current smart meter: produces NEM12 interval data.
Solar installed since about 2020: the connection almost certainly carries a smart meter, so NEM12.
An older basic meter read by a person: produces NEM13 accumulation data.

If you already hold a file, our guide on how to understand the NEM12 CSV format shows what a valid file looks like, line by line.

Why Interval-Data Analysis Tools Require NEM12

Interval-data analysis tools require NEM12, because every question they answer is a question about timing. Only interval data records timing.

Time-of-use costs: matching use to peak, shoulder, and off-peak windows needs each interval, not a yearly sum.
Solar self-consumption: separating the generation you use on site from the generation you export needs 30-minute or finer readings.
Load profile: a daily or seasonal shape exists only when the file holds many readings per day.
Detailed report output: a detailed report of morning and evening peaks needs interval data, and one accumulated figure cannot produce it.

Try our NEM12 Smart Meter Data Analyzer Tool

What a NEM13 Total Cannot Show

A NEM13 file holds one number where a NEM12 file holds tens of thousands. No method reconstructs a time-of-day pattern from a single total.

Time-of-day use: a single total gives no morning, evening, or overnight split.
Solar export windows: a single total cannot show when the B1 register exported.
Peak and off-peak share: nobody can divide a single total across tariff windows.

Once you hold a NEM12 file, our free NEM12 Smart Meter Data Analyzer charts each register in your browser, and our guide on how to visualize NEM12 data with charts goes further.

Which Portal Option Delivers NEM12 Interval Data?

A menu label on a meter portal is not the same thing as the file format behind it. Option names differ between networks, and they change over time. Powercor, Citipower, and United Energy share the Victorian MyEnergy Portal, and the table below names its options.

Portal option you might see	What the option returns
DETAILED or VECFORMAT (Victorian MyEnergy Portal)	30-minute interval data in NEM12 CSV Format.
SUMMARY (Victorian MyEnergy Portal)	Monthly totals in CSV format, and not NEM12 interval data.
Daily CSV or dashboard CSV, on other portals	Varies by portal — often a simplified totals view rather than NEM12 CSV.

One check settles any label you do not recognise.

Open the downloaded file in a plain text editor.
Read the first row of the file.
If the row begins with 100,, the file is NEM12 CSV.
If the row is a column header such as Date,Time,Usage, the file is a simplified export.

The steps to reach the right download differ for every DNSP. Our guide on how to download your smart meter data walks through the portals one by one.

You Cannot Request the Wrong Meter Data Format

You do not choose between NEM12 and NEM13. You request smart meter data, and the rules decide the meter data format you receive.

The obligation is regulatory: the National Electricity Rules and the AEMO Metering Data Provision Procedures require your DNSP and your electricity retailer to supply interval data from smart meters in NEM12 CSV Format.
The format matches your meter: your DNSP reads your NMI, finds the meter registered against it, and sends NEM12 for an interval meter or NEM13 for an accumulation meter.
You cannot pick the wrong one: AEMO rules require the correct format for your connection.

Ask your DNSP or your electricity retailer for your smart meter data. A smart meter connection returns NEM12. A legacy accumulation meter returns NEM13, and (as of 2026) the Australian smart meter rollout targets full coverage by 2030.

Frequently Asked Questions

What is the difference between NEM12 and NEM13? NEM12 is interval meter data from a smart meter, recorded every 5, 15, or 30 minutes. NEM13 is accumulation meter data from a legacy meter, holding one total between manual reads.
Is NEM12 interval data or accumulation data? NEM12 is interval data. It stores many readings per day, which is what time-of-day analysis needs.
What is accumulation meter data? It is a running total of the energy used between two manual meter reads, with no record of when the site used it.
Do I have to choose between NEM12 and NEM13 when I request my data? No. You request smart meter data, and your DNSP or your electricity retailer supplies the format that matches your meter.
What does the DETAILED or VECFORMAT option mean on a portal? On the Victorian MyEnergy Portal, DETAILED and VECFORMAT return 30-minute interval data in NEM12 CSV Format. Option names and availability differ on other portals.
What does the SUMMARY option give me? On the Victorian MyEnergy Portal, the SUMMARY option returns monthly totals in CSV format, and not NEM12 interval data.
Why do solar and time-of-use tools reject a NEM13 file? Those tools depend on timing, and one accumulated total cannot show consumption or export by time of day.
How do I check that a downloaded file is really NEM12? Open the file in a plain text editor and read the first row. A NEM12 CSV file starts with 100,.
I have a smart meter. Will I ever receive NEM13? No. A smart meter records interval data, so your DNSP or your electricity retailer supplies NEM12.
Is NEM13 on the way out? Yes. As of 2026, the Australian smart meter rollout targets full coverage by 2030, and legacy accumulation meters are retired as that work proceeds.
How does my NMI affect the meter data format I receive? Your NMI identifies your connection point, and your DNSP uses it to find the meter registered against that connection.
Who must give me my smart meter data? Your electricity retailer and your DNSP must supply it, under the National Electricity Rules and the AEMO Metering Data Provision Procedures.
What is MDFF? MDFF is the AEMO Meter Data File Format specification. It defines both the NEM12 interval structure and the NEM13 accumulation structure.
Can I use my annual bill total in place of NEM12 data? No. A bill total carries no interval detail, and a detailed report of daily patterns needs an interval export.
What should I do if a tool reports that my file is "not NEM12"? Check the first row, then request the export again from the portal. Our guide on how to avoid NEM12 CSV data gotchas covers the common causes.
What do register codes such as E1 and B1 mean in a NEM12 file? E1 is a mains grid import register, and B1 is always solar export, as our guide on how to interpret your smart meter data explains.

Try our NEM12 Smart Meter Data Analyzer Tool

Glossary

AEMO: Australian Energy Market Operator — the body that administers the National Electricity Market and defines and maintains the NEM12 specification.
B1: In the NEM12 Format, the Meter Register code for Solar Export — electricity generated on site and fed back to the grid, typically measured in kWh.
Check Digit: The 11th digit of a full NMI — calculated from the first ten digits to detect transcription errors; some DNSP portals require it. Also called a 'Checksum'.
CSV: Comma-Separated Values — a plain text file in which each row is a record and fields are separated by commas.
DNSP: Distribution Network Service Provider - the company that owns and operates the physical poles and wires of the local electricity network, and usually provides the smart meter data portal. Not the same as your Electricity Retailer. See also: Electricity Retailer.
E1: In the NEM12 Format, the Meter Register code (or NMI Suffix) for the sole/main/primary mains grid import channel — electricity drawn from the network. Where there is No (Solar) Generation on site, this is the Total Consumption. Typically measured in kWh.
Electricity Retailer: The company that sells electricity to the consumer, issues the bill, and manages the account. Not the same as your DNSP (Distribution Network Service Provider) which owns and operates the network. See also: DNSP.
Interval Data: Energy readings recorded at fixed time steps — typically every 30 minutes (but sometimes 5 or 15 minutes on newer meters) rather than as a single billing total. This allows charging different Tariffs at different times of day or days of the week. See also: Time-of-Use (TOU) Tariff.
kW: KiloWatt — the standard unit of (Electrical) Power: 1,000 Watts of Power used continuously for one hour is equivalent to 1000 Watt-Hours or 1 KiloWatt-Hour of Energy. Power is not an Amount of Energy but a Rate of Energy Transfer. See also: kWh.
kWh: KiloWatt-Hour — the standard unit of (Electrical) Energy: 1,000 Watts of Power used continuously for one hour is equivalent to 1000 Watt-Hours or 1 KiloWatt-Hour. NEM12 CSV records Electricity Use in kWh. See also: kW.
Load Profile: The pattern of a site's electricity use over time, derived from its interval data. The granularity or resolution of the Profile is the Interval Length (eg. 30 Minutes, Hours), and is typically based on averages for a longer period (eg. Months, Seasons).
MDFF: Meter Data File Format — AEMO's file format specification for metering data, defining both the NEM12 interval structure and the NEM13 accumulation structure.
Meter: The physical device at the premises that measures and records electricity import and export.
Meter Portal: An online portal operated by a DNSP (or retailer) where customers can log in to view and download their Smart Meter Data. See also: DNSP, Electricity Retailer.
NEM: The Australian National Electricity Market — the interconnected electricity grid covering Queensland, New South Wales, Victoria, South Australia, Tasmania and the ACT. Western Australia and the Northern Territory operate separate grids.
NEM12: The AEMO file format (version 12) for exchanging Interval Data from Smart Meters across the Australian National Electricity Market (NEM). NEM12 Format records the Amount of Energy per Time Interval in kWh. And also other types of data, using specific types of labelled rows or records (100, 200, 300, 400, 900) to record different types of data. This makes it a 'Semi-Structured' 'Non-Tabular' Format. See also: AEMO, NEM, kWh, Semi-Structured, Non-Tabular.
NEM12 CSV: A NEM12 File stored as comma-separated values — the form most DNSP and retailer portals distribute. See also: NEM12, CSV.
NEM13: The AEMO Format for accumulation (non-interval) meter data — a total per read period rather than time-stamped intervals.
NMI: National Metering Identifier — the unique 10-digit identifier for an electricity connection point (11 with the Check Digit), permanent to the property. Note that the electricity connection point identified by the NMI, typically has multiple NMI Suffixes, and can have multiple Physical Meters. See also: Check Digit, NMI Suffix.
NMI Suffix: In the NEM12 Format, the short two-character code (E1, E2, E3, B1, B2, Q1, K1) identifying a specific Meter Register for recording electricity flows on the mains electricity connection identified by that NMI — also called the Meter Register or Register Code. See also: NMI, NEM12.
Non-Tabular: Data that does not fit a single consistent grid — in NEM12's case because of its semi-structure, hierarchy and mixed-record layout.
Self-Consumption: The share of the electricity generated by your own solar panels that your household uses on site, rather than exporting it to the grid.
Semi-Structured: A data format that follows strict syntactic rules (e.g. comma separation, defined record codes) but does not enforce a consistent column schema across all rows. NEM12 is a Semi-Structured Format. See also: NEM12.
Smart Meter Data: Electricity import and export readings recorded by a digital interval meter at regular intervals. In Australia, typically supplied in NEM12 CSV Format with 30 Minute Intervals. See also: NEM12 CSV.
Time-of-Use (TOU) Tariff: A tariff with different prices at different times of day or days of the week (Peak, Shoulder, Off-Peak).

Try our NEM12 Smart Meter Data Analyzer Tool