Electricity use through the day, and across the seasons

On a typical day, power demand in New Zealand generally follows a familiar pattern, with curves on a graph looking like the humps of a camel.

In the morning, when people are making breakfast and having showers before work or school, demand rises after lows overnight, and then sinks during the day before rising again in the evening, due to cooking, heating, lighting and bathing.

Patterns tend to change during school holidays, and on weekend and public holidays.

Demand for electricity rises considerably in winter, although there are also variations depending on which part of the country you are in and your choice of heating, cooking and hot water heating options.

The average medium-sized home in NZ uses almost 8000 kWh (kilowatt hours) of electricity a year (Auckland 7576 kWh, Wellington 7972 kWh, Christchurch 8131 kWh, Dunedin 8210 kWh).

In parts of the country where more homes are heated using electricity in winter consumption could be more than 20 percent higher than the average, while homes using wood burning fireplaces for heating could be 16 percent or more lower.

As expected, power consumption tends to be highest on cold winter nights, when people are heating their homes and cooking dinner.

But there can also be cases when summer consumption surges, for example during hot and dry weather, when many people are using air conditioners at home and farmers are irrigating more than usual.

Transpower notes that in the decade from 2012 to 2022, demand for electricity in winter increased by 0.4 percent, or four times the average summer growth.

It attributes the difference in growth between the two seasons mostly to the increasing electrification of heating, and says this will likely continue as carbon prices push up the cost of fossil fuels.