Power BI Desktop is free to download, install, and use. In addition to simply sharing Power BI files (.pbix), which are the files that are created by the Power BI Desktop program, Microsoft provides a free method of using Power BI Service so that you can publish and share reports via a featured called Publish to web. Publish to web creates a web browser link or URL to a report that's published in the Power BI Service. While this URL is long and cryptic and these reports are not indexed by search engines, anyone with the link can browse the report anonymously. This means that there is no real security other than simple obfuscation.

It is important to note here that Publish to web is the only sharing mechanism available with a free license of Power BI. All other sharing, collaboration, and export features are not available in the Power BI Service. This includes app workspaces for collaboration, sharing of reports and dashboards, as well as exporting to PowerPoint/CSV and embedding within Microsoft SharePoint.

The free licensing of Power BI also comes with certain restrictions on the automatic refreshing of data. Only online sources of data can be refreshed automatically. This means any data that is accessible online via the internet. On-premises data sources that require an on-premises data gateway or any live (DirectQuery) sources are not supported. Furthermore, even the online data sources can only be refreshed eight times per day, and the minimum time between refreshes is 30 minutes.

Finally, the free Power BI license restricts the total size of any single data model that's published to the Power BI Service to 1 GB and the total size of all data models that are published to the Service for each user to 10 GB.