It is not possible to run Power BI reports locally right now, but sometime before the 1st of July 2016, users who have SQL Server 2016 Enterprise Edition per-core and active Software Assurance [SA] can deploy Power BI Report Server. This means that no one is going to have to wait for SQL Server 2017 for Power BI on premise as that will be available sometime in June. The functionality in SQL Server 2017 SQL Server Reporting Server [SSRS]. Community Technology Preview edition is going to be available in Power BI Report Server, with the addition of the ability to include custom visuals, which the CTP version did not do. The Power BI Server includes all of the functionality of SSRS This means that users will not need an SSRS Server and a Power BI Server, as the Power BI Server will be able to both. If you want to migrate all of the reports created in SSRS from 2008 R2, and SSRS Mobile Reports, you can migrate these reports to the new Power BI Report Server, provided of course you have SQL Server 2016 Enterprise per-core edition with SA. The Power BI Report Server will be a separate install with separate release schedules. Microsoft has announced that they are planning on doing updates at a greater frequency than SQL Server. Power BI Report Server will also be able to publish reports to mobile devices as well. If the reports uses data in the cloud, you can employ a Data Gateway as the Power BI Reporting Server can use the gateway to access cloud data. Of course if all of the data in the report is located on-premises, no gateway will be required.
I’m a bit disappointed that the on-prem installation will not allow you to create dashboards, but perhaps that will come in time.