ENERGY · 25 SEPTEMBER 2026

Peak electricity is different from
total energy.

A building can use the same number of kilowatt-hours and create very different demands on the electricity system depending on when those kilowatt-hours are used.

THE PROBLEM

We often measure energy after the event.

Annual or monthly energy use is useful, but it can hide the shape of demand. A system that uses 100 kWh steadily across a day behaves differently from one that uses the same 100 kWh in a short high-demand window.

The Electricity Authority identifies morning and evening demand peaks in New Zealand and is actively working on demand-side flexibility, including ways to shift electricity use away from high-demand periods.

THE BETTER QUESTIONNot only “how much energy do we use?” but “when does the system need it?”

Timing creates another design variable.

Once timing matters, products can do more than consume energy. They can store, shift, delay or respond. Hot-water cylinders are a familiar example. Thermal storage can extend the idea to heating and cooling. Controls can decide when equipment should run without changing the service the building needs.

The Electricity Authority says flexibility can reduce the need for additional generation or network investment by making better use of demand at different times.

HIGH DEMANDMorning + evening peaks

SHIFTStore or move flexible loads

LOWER DEMANDUse energy when the system has more room

REFRAME

What if the building could choose its timing?

That is where storage and intelligent controls become more interesting. They can separate the moment energy is produced or purchased from the moment comfort or hot water is actually needed.

WHERE ELSE CAN WE USE IT?

Peak-shifting is not only an electricity-market problem.

Heat pumps

Pre-heat or pre-cool when conditions are favourable, then reduce runtime during constrained periods.

Thermal storage

Store useful heat or cooling so the equipment and the building do not have to peak at the same time.

Commercial loads

Coordinate flexible processes, hot water and environmental systems around operating conditions.

EVOLUTIONFX TAKE

Energy efficiency has a time dimension.

We are interested in products that reduce energy use and also give buildings more freedom over when energy is consumed.

Explore thermal energy storage →

RESEARCH & FURTHER READING

Electricity Authority · Demand-side flexibility in a highly renewable power system
Electricity Authority · Managing peak electricity demand

Peak electricity is different fromtotal energy.