This site keeps your choice on this device, in your browser's local storage (it is not a cookie), so it does not ask again. It also keeps a small cache of its own files so pages load faster.
This site uses Google Analytics 4 to count visits. Before you choose, and if you choose "Accept required", Google Analytics receives an anonymous signal for each page you open, without cookies and without a persistent identifier. Google still receives your IP address, the page address, the referring site and browser details, as any web request does. Google says it uses them for measurement and, while consent is denied, for statistical modelling only. This data can be processed outside your country, including in the United States.
If you choose "Accept all", Google Analytics also sets its own cookies (_ga and _ga_*) to recognise returning visitors and show us which pages, countries and tools are used. Google acts as our processor, and Google signals and ad personalisation are switched off.
If you choose "Accept required", Google Analytics sets no cookies and nothing beyond that anonymous signal is sent. If your browser sends Global Privacy Control, no request is made to Google Analytics at all. The whole site works either way. You can change your choice at any time with "Cookie choices" in the footer.
4 free tools for questions people ask about electricity: how countries differ, what your own use emits, and when a grid is cleanest. Country figures are Ember annual statistics (mostly 2025); the hourly pattern comes from grid operator data and is kept apart from the Ember figures.
How do these countries differ?
Choose two to four of 215 countries and see generation, demand, demand per person, carbon intensity, low carbon share, the fuel mix and the trend since 2000 side by side. The address bar keeps your choice, so you can share it.
Data: Ember annual statistics, latest year per country (most often 2025).
Open the tool: Compare countriesWhat is the carbon footprint of my electricity?
Enter a country and your home's yearly or monthly kWh, an electric car's distance and efficiency, or an appliance's power and hours. It returns kilograms of CO2 at that country's average carbon intensity (world average 460 gCO2/kWh in 2025), next to the cleanest and dirtiest large grids.
Data: Ember annual carbon intensity, 2025.
Open the tool: Carbon footprint calculatorWhen is electricity cleanest?
Pick one of 106 grid zones and see the typical low carbon share of generation for each hour of the local day, with the best and worst hours marked. It is a pattern from recent days, not a forecast.
Data: Grid operator hourly generation (EIA and ENTSO-E), latest complete days.
Open the tool: Cleanest hoursWhich grid serves my ZIP code?
Type a US ZIP code to see its predominant electric utility and EIA balancing authority, with a link to that grid's live page and to your state.
Data: EPA eGRID ZIP crosswalk and EIA-861 (annual reference data, not live).
Open the tool: ZIP code grid lookup