Load management | Vector Limited

Load management refers to the way we reduce electrical load on our network during periods of high or 'peak' electrical demand.

There are times when demand for electricity becomes very high and results in more electricity than usual being used across the network. This generally occurs most often in winter, especially in the peak times of morning or early evening.

The areas we are currently load managing can be seen on a map here.

Why do we load manage?

Turning off the hot water heating during peak times helps reduce the amount of electricity being used. Hot water can be heated at non-peak times rather than during the peak when households need electricity for heating and cooking. Essentially, it is a simple, effective way of flattening out the peaks and troughs of demand for electricity. There may also be times when Transpower, or another electricity industry participant, requests that Vector carry out load management.

Two load management systems operate on our network.

Depending on which area you live in one of two options is used for turning off hot water heating.

In Auckland, most parts of Rodney, Manukau and on our Papakura network a system known as ripple control is used. Once power usage reaches maximum limits, the computerised system in our network control room sends out coded signals across the network. When the signal reaches a household meter board a relay recognises the signal and switches off the electricity supply to the hot water cylinder. When power demand eases, another signal is sent out to turn the hot water cylinders back on.
On the North Shore, in Waitakere, and parts of Rodney a pilot wire system is used. Once power usage reaches maximum limits, the computerised system in our network control room sends out signals to the relevant substations around the region. These substations have switches which then send out the load management instruction over a separate wire from the mains supply. This wire is connected to a relay in a household meter board, which switches off electricity supply to the hot water cylinder. When power demand eases, another signal is sent out to turn the hot water cylinders back on.

The benefits of a load management pricing plan for customers

Customers on a price plan where Vector can control their hot water pay a lower price for line charges than those who do not allow control of hot water. The lower controlled pricing plan applies over the whole year, even though load management is generally restricted to the winter months.

All arrangements to move to or from a controlled price plan must be made through your electricity retailer. Costs may apply.

Key facts and answers to common questions about hot water and load management are available here.