Green Power Indicator is a Firefox addon designed to enable you to visualize if the website has a green power state or not. Green Power Indicator displays whether the called site is hosted on a server, which is operated with environment-friendly produced electricity. If the power state is unknown is shown. Otherwise the GPI shows the quality of the green power of the websites server via a small icon. To reduce data transfer, the green energy data of already visited sites is stored locally. This cache can be viewed in the settings menu and can be deleted by the user. By default encrypted connections (HTTPS) are not checked for their green power status.