Net generation: Total gross generation minus the electricity used by the generator for auxiliary services (e.g. lighting, coal grinders) and internal losses. It includes generation from cogeneration plants.
1 Gigawatt hour (GWh) = 0.0036 Petajoules (PJ).
Solar energy: Distributed Solar PV Generation has been estimated using Electricity Authority data.
Waste heat: includes heat from chemical processes (e.g. fertiliser industry).
Total renewables: Hydro, Geothermal, Biogas, Wood, Wind, and Solar.
Gigawatt hours: abbreviated as GWh, is a unit of energy representing one billion watt hours and is equivalent to one million kilowatt hours.
Changes to data collection/processing
Estimated sales method:
The Ministry uses quarterly data on grid exit point (GXP) demand sourced from the Electricity Authority to produce its series of electricity consumption based on estimated sales (previously referred to as the “historically consistent methodology”).
The Ministry has reviewed and updated the mappings of GXPs to particular industries or sectors that are used for this method to better reflect the activity in these sectors.
This has resulted in revisions to the annual series of consumption based on the estimated sales method for 1990 onwards.
Electricity use for transport:
Prior to July 2020, the Ministry used an annual estimate of electricity use for transport from a previous modelling exercise. This was assumed to all be used in the commercial sector, and was deducted from volume sold to the sector to ensure that it was not being double-counted. However, this estimate did not reflect changes to electricity use for transport that have occurred since the previous modelling exercise was undertaken in 2012.
The Ministry has introduced a new method for estimating electricity use for transport using a range of sources. As this electricity use falls in both the commercial and residential sectors (i.e. households charging electric vehicles), electricity use for transport is now stated as a separate item in the quarterly and annual sectoral consumption statistics.