What it reallhy looks like:
Most all of this infrastructure is Privately Owned
Investor Owned Service Areas in Blue:
early 1900s designated
Power Administration Areas for 34 states.
Post WW II Regulatory sectors
The Regulatory Map:
The Control Points to the overall Grid:
And
so this is how the simple is made complex.
As a result, the entire system is now prone to congestion problems:
The main problem stems from a growing inequity in individual states use of electricty and either their need for imports (due to lack of generating facilities) or their ability to export (due to over capacity).
But percentages don't matter as much as actual megawatt hours of electricty flow:
Clearly, powering California is a problem. West Virginia basically exports to Virginia (which is why they should be 1 state).
Note that the combined exports of California's neighbors (WA,OR,AZ,NV) are only 34 million
of the required 68 million MWHs 
this means long transmission haul
electricity is needed to keep CA powered.