Electricity Emissions Calculator
The carbon emissions of your electricity use from the kilowatt-hours on the bill and the intensity of your grid — per period, per year and per day — with the effect of a green-power share and what the figure equals in driving.
Every kilowatt-hour from the grid carries the emissions of the generators that made it: near zero for hydro, nuclear and wind, about 400 grams of CO₂ for gas, 900 or more for coal.
How the electricity emissions calculator works
Every kilowatt-hour from the grid carries the emissions of the generators that made it: near zero for hydro, nuclear and wind, about 400 grams of CO₂ for gas, 900 or more for coal. Your grid's average is published by its operator, and it is very different from one place to another — which is why the intensity is an input with a market default rather than a constant. Green-power purchases offset a share; the rest is your electricity footprint.
Formula: kg CO₂e = kWh × intensity (g/kWh) / 1000 × (1 − green share)
Worked examples
| Inputs | Emissions for the period (kg CO₂e) | Note |
|---|---|---|
| A quarter's usage on the local grid | 780 | per market intensity |
| Half covered by solar | 390 | emissions halve |
| A coal-heavy grid | 1,080 | the same use, far more carbon |
FAQFrequently asked questions
What is grid intensity?
The average emissions per kilowatt-hour of the electricity your grid supplies, from the mix of generators running. It ranges from under 50 g on hydro-heavy grids to over 800 on coal-heavy ones.
Where do I find my grid's figure?
From the grid or market operator, the national greenhouse accounts, or a live-intensity website. The default is a recent national average; a state or regional figure is better.
Does green power really reduce it?
Accredited green power buys renewable generation on your behalf and is counted as zero-emission in most schemes. Your own rooftop solar reduces the grid electricity you use in the first place.
How does electricity compare with driving?
A typical household on a fossil-heavy grid emits about as much from electricity as from a car driven 15,000 km a year. On a clean grid, the car dominates by far.
Does the time of day matter?
Yes — intensity is lowest when wind and solar are strong and highest in the evening peak. Shifting usage to sunny hours cuts emissions as well as, on some tariffs, cost.
Where these figures come from
- International Energy Agency — Energy Efficiency — appliance consumption and standby power context
- Australian Energy Regulator — the Australian energy market regulator
Last checked: September 2026. Appliance power figures are typical ratings; check the label on your own equipment, which is authoritative for it.