Here is a link to an excellent summary of many of the issues surrounding the Susquehanna-Roseland line.
This is a review of the S-R situation on the Web site of the Raritan Valley (NJ) Sierra Club, written because the Raritan Valley would be affected by the Hudson-Branchburg line attached to the eastern end of the S-R line.
The article contains the following image that puts the pieces of the Project Mountaineer puzzle into clear focus:
Note the location of the connections to “I-765 Interstate Project” and “MAPP Project”. The I-765 is AEP’s cute name for their Project Mountaineer transmission project which includes PATH and TrAIL. Put this map together with PJM’s Project Mountaineer map here, and you get the real picture of how the S-R/Branchburg-Hudson lines connect with PATH.
The S-R project ends at Roseland, NJ. As you can see on the map, the additional Branchburg-Hudson (as in Hudson River) extensions provide a direct connection from the Project Mountaineer lines on the west and New York City on the east.
The article also notes that PPL, the power company building the PA section of the S-R line, is not only planning a new nuclear reactor at its Berwick, PA plant to feed the S-R line, but is also planning to expand a nearby coal-fired plant.
The MAPP connection shown on the map is now dead, because Delmarva Power has dropped the entire northern section of that line through Delaware. This was the direct result of better management of electricity demand by PJM Interconnection and its member power companies, and, of course, strong organized resistance from citizens in Maryland and Delaware.