What interval data is
A smart meter records how much electricity flows through it every 30 minutes, and some every 5 minutes. A year of that is more than 17,000 readings, and together they show your home’s whole pattern: when it wakes up, when it is empty, what runs overnight and when the big loads switch on. A bill compresses all of that into one number per tariff.
You can download it free from your retailer or distributor. See how to get your smart meter data. It usually arrives as a NEM12 file, the industry standard set by the Australian Energy Market Operator.
What is inside a NEM12 file
Open the file in a text editor and you will see lines of comma-separated values. Each line starts with a record number that tells you what it is:
- 100
- The header: the file format and when it was created.
- 200
- Details for one meter channel: your NMI (National Meter Identifier), the channel code, the unit (usually kWh) and the interval length, 30 or 5 minutes.
- 300
- One day of readings: the date, then one value per interval (48 for 30-minute data), then a quality flag.
- 400
- Quality detail when different intervals in a day have different quality.
- 900
- The end of the file.
The codes that matter
- E1 (and E2, E3…)
- Energy you imported from the grid. A second "E" channel is often a controlled-load circuit, such as electric hot water.
- B1
- Energy you exported to the grid, usually from solar panels. If you have solar and there is no B channel, ask why.
- Q and K channels
- Reactive power, used by the network. You can ignore them.
- Quality flag A
- Actual: read from the meter.
- Quality flags S, F or E
- Substituted, final substituted or estimated: the meter did not report and a value was filled in. A few are normal. Long runs mean the meter had a communications problem.
Four things to look for
- 1. Your baseload
- The lowest steady usage overnight, around 2 to 4am, when nothing is deliberately on. This is fridges, standby devices, network gear and anything left running. Multiply the half-hourly figure by 48 to see what it costs you every day. See standby power.
- 2. Your evening peak
- Most homes peak between 4pm and 9pm, which is exactly when time-of-use plans charge the most. A large peak is the strongest sign that a single-rate plan may suit you better, or that moving loads would pay. See time-of-use vs single rate.
- 3. Midday
- How much you use between 11am and 2pm decides whether a free-hours offer like the Victorian Midday Power Saver or the Solar Sharer is worth anything to you.
- 4. Exports
- If you have solar, compare your midday exports with your evening imports. A big gap between the two is the case for a battery, or for running appliances during the day. See is a home battery worth it.
Avoid these mistakes
- Do not save the file from a spreadsheet. Spreadsheets reformat dates and long numbers, and a re-saved file can stop parsing.
- Check the date range. You want at least 12 months, so every season is in.
- Remember the times are usually in standard time all year, so in summer the readings sit an hour off the clock on your wall.
- Do not compare 5-minute and 30-minute values directly. A 5-minute value is one-sixth of the period.
Let us read it for you
Upload your NEM12 file to your EnergySorted account and we chart your average day, shade it with your distributor’s actual peak, shoulder and off-peak hours, and work out your baseload and when your peaks fall. Then we cost every plan at your address on that exact pattern, including time-of-use plans, free-hour plans, demand tariffs and time-varying feed-in tariffs, which a bill alone cannot price properly. Start with a free bill check, then add your interval data. To see how your total compares, read how much electricity a house uses per day.
Frequently asked questions
What is smart meter interval data?
A record of how much electricity your home used, and exported, in every 30-minute (or 5-minute) period. A year of it shows exactly when you use power.
What does E1 and B1 mean in my meter data?
E1 is electricity imported from the grid; B1 is electricity exported to it, usually from solar. A second E channel is often a controlled-load circuit.
What does a quality flag of S or E mean?
The meter did not report that period and a substituted or estimated value was filled in. A few are normal; long runs suggest a communications fault worth raising with your retailer.
Can I open a NEM12 file in Excel?
You can look at it, but do not save it from Excel. Spreadsheets can reformat dates and numbers and break the file for other tools.
What is my baseload?
The steady power your home draws when nothing is deliberately switched on, usually visible between 2am and 4am. Fridges, standby devices and network equipment make it up.
Why are my readings an hour off in summer?
Meter data is usually recorded in standard time all year, so during daylight saving the readings are an hour behind the clock.
How much data do I need?
At least 12 months, so that summer and winter are both included. Less than that can make a plan look better or worse than it really is.
Can EnergySorted read my file?
Yes. Upload it in your account and we chart it against your distributor’s time-of-use hours and cost every plan at your address on your actual half-hourly pattern.