Energy retailers rely on a centralised database that identifies energy meters by meter ID, serial number, and street address/location.

Electricity meters are identified by their NMI, or National Metering Identifier.

Gas meters can have one of two separate meter ID types, depending on your location. In Victoria, Queensland and South Australia, your gas meter will have a MIRN, which means Meter Installation Reference Number or Meter Installation Registration Number.

In NSW, gas meters are identified by DPI or Delivery Point Identifier.

These two concepts do the same thing - providing the identifying ID for your gas meter.

Either a DPI or MIRN number will be displayed in your gas bills, and will also be visible on the meter itself.