According to Microsoft PowerBI team:
One of the most awaited and requested feature is now available in Power BI. Starting today, in Power BI you can refresh datasets connecting to your on-premises sources such as SQL Server. Any workbook created using Power BI Designer, Power Query or Power Pivot are supported. For these datasets the Power BI Personal Gateway enables automated refreshes against on-premises data sources in your organization, all via a single gateway you can install directly on your desktop machine.
All common data sources are supported:
- SQL Server
- IBM DB2
- SharePoint List (on-premises)
- File (CSV, XML, Text, Excel, Access)
- On-premises SQL Server Analysis Services models (uploaded data; not live connections)
- Custom SQL/native SQL
this is really exciting – even a normal workstation can do the work!