I am not sure what this means.

Grid capacity can mean that every segment is now being fully utilized.

The Grid has X number of inputs and Y outputs, (some if not all can be both?)

Boosting capacity would seem to me to be most interesting as it pertains to routing.

If San Diego is experiencing an uncommon need for electricity, then paths are routed to increase supply(?). But San Diego probably wont have that many inputs (?) and each of them probably has some max capacity (?).

Ok so you need to route as much power there as can be used.

How would this system make this better?

would it allow the grid operators to route more power over existing lines if weather permitted? and the opposite if the weather does not permit.