I always get asked this question, so I have captured the information here so I can always get the links
The TFS Power tools consists of a few tools that can only be run on the server (such as the Best Practices Analyzer), but the majority are exposed through the Visual Studio IDE.
To run the server power tools you need to install the power tools on the TFS Application Tier, and the server of the Power Tools need to match the version of your TFS server.
On the client however you need to match the version of the TFS Power Tools with your Visual Studio client. If you have VS 2013 installed, you need to install the TFS 2013 power tools. Regardless of which version of TFS you are targeting. To clarify, here are some examples:
VS 2013 connecting to TFS 2013: Install TFS 2013 Power tools
VS 2013 connecting to TFS 2012 or TFS 2010: Install TFS 2013 Power Tools
VS 2012 connecting to TFS 2013: Install TFS 2012 Power Tools (since the power tools need to match the VS version)