City Energy Demand Calculator
The electricity a city or suburb uses in a year and draws at peak — from population, per-capita consumption, a load factor, and how much rooftop solar offsets.
Annual energy is population times per-capita kilowatt-hours.
How the city energy demand calculator works
Annual energy is population times per-capita kilowatt-hours. Peak power is the harder number: it is the average power divided by the load factor, which says how flat the demand curve is. A load factor of 0.55 means the peak is nearly twice the average.
Rooftop solar reduces the annual figure but does little for the evening peak, which is why grids are sized on the peak and not the total.
Formula: annual = population × kWh per capita; peak = annual / 8,760 / load factor
Worked examples
| Inputs | Annual demand (GWh) | Note |
|---|---|---|
| 180,000 people | 936 | 936 GWh, peak about 194 MW |
| A flatter load | 936 | a lower peak for the same energy |
| Heavy electrification | 1,440 | a much larger network |
FAQFrequently asked questions
How much electricity does a person use?
Four to seven thousand kWh a year in most developed countries, all sectors included. Households alone are about a third of that.
What is a load factor?
Average demand divided by peak demand. A city runs 0.5 to 0.65; a factory on continuous shifts can exceed 0.9.
Why does the network care about peak, not total?
Because every wire and transformer has to carry the peak, which happens for a few hours a year. Total energy is what you pay for; peak is what you build for.
Does rooftop solar reduce the peak?
Barely, in most cities — the peak is early evening after the sun has gone. Batteries and demand response shift it; solar alone does not.
What is a zone substation?
The substation feeding a suburb, typically 30 to 100 MVA. The count here is a planning estimate at 90% utilisation.
Where these figures come from
- UN-Habitat — Urban Indicators Guidelines — density, green space and public space benchmarks
- World Health Organization — Urban green spaces — the 9 m² per person minimum
- ITE — Parking Generation Manual — parking demand rates by land use
- Australian Bureau of Statistics — Regional population — Australia's national statistics agency
Last checked: September 2026. Default per-capita rates are mid-range figures from national statistical agencies and utility reports; every one is an input you should replace with the local figure.