Electricity Industry terminology made simple.

ICP number

Your property has a unique Installation Control Point (ICP) number identifying it on the New Zealand electricity network. You can find this on your current power bill somewhere under the invoice number. It consists of 15 digits – mostly numbers with a few letters at the end.

Kilowatt hour

A kilowatt hour (kWh) is the way power usage is measured on your meter. The electricity industry uses kWh to measure how much power you use. And so do most companies that manufacture electrical products. When you shop for new electrical appliances, you may notice that most are labelled with a star rating and the number of kWh the appliance will typically use per year. We measure the power you use every month in kWh, and charge you an amount per
kWh for your usage.


A tariff is a way of pricing electricity based on the way your meter is set up. There are many different names for the various tariffs across the power industry. But they will normally indicate a time of use (e.g. Day and Night) or control (e.g. Uncontrolled, Anytime, Economy).

Controlled/uncontrolled metering

If you have controlled/uncontrolled metering the power your network company is able to 'control' is measured separately to the power that they can't. Most networks will give you a discounted rate on the power they can control – which is usually the supply to your hot water cylinder. This is because they are able to switch off the 'controlled' portion of your supply for short periods, for example when the demand on their network is high or there are faults or Emergencies on their lines.

Day/night metering

If you have a day/night meter your 'day' usage and your 'night' usage are measured separately. Many network companies charge a lower rate for the power you use at night time – which goes from 11pm to 7am in most areas.

Night only metering

Night only metering means the power supply to certain appliances, for example a night store heater or hot water cylinder, can only be turned on at night. Night time goes from 11pm to 7am in most areas. Many network companies charge a lower rate for the power you use at night time.

Night boost metering

Night boost metering means the power supply to certain appliances, for example a night store heater or hot water cylinder, can be turned on at night, between 11pm and 7am, and for one to five hours in the afternoon (depending on your network).

Smart meters

Most properties in New Zealand now have smart meters. Smart meters mean we get more accurate usage information and they don't need a human to manually read them. We get your smart meter readings daily, and they show your power usage down to the half hour.

Smart meters also differ from the old 'dumb' or analogue meters by being able to measure power usage accurately across different time periods (e.g. days, nights and weekends) in the one meter. They also have two-way communication abilities to both enable remote meter reading, and also to enable instructions to be sent to the meter e.g. to remotely disconnect, or reconnect a property. Visit the Electricity Authority website for more information about smart meters.

The wholesale market

This is another term for the New Zealand Electricity Market (NZEM). The New Zealand Electricity Market is regulated and overseen by the Electricity Authority (EA). Electricity generators (or wholesalers) sell their power to large industrial users and retailers through the wholesale market. The Electricity Authority website has more information on how this all works.

Network or lines companies

The network companies (also known as line companies or distributors) own and look after the power lines that transmit the electricity from the national grid to your property. There are many different network companies in New Zealand although each company operates a monopoly in its given area.

Transpower look after the national grid which carries electricity around the country delivering power from power stations to local lines companies. Your local lines company is in charge of the network that delivers it to your house – these are the guys we get on the job when there's an outage.

Electricity retailers

An electricity retailer, or power company, or electricity provider, is a company that sells electricity to customers. Retailers buy electricity from the wholesale market and sell it on to you.