The Revit labs have come out with a great tool for sustainable design. This tool allows you to examine solar radiation on various surfaces of your building information model. The amount of solar energy is based on the buildings location and weather data in the model. You can download the preview here: Download the Free Solar Radiation Technology Preview from Autodesk Labs
What a great tool to help you decide where to place your PV Panels for maximum efficiency.
Check out the video here: Solar Radiation Technology Preview Video
I hope this also works with Revit 2011 MEP. If it does I will check it out and see what the reports that it generates can do for us electrical engineers.