  This paper summarizes the operational challenges imposed by integration of
renewable electricity generation units in transmission level where the most
common renewable generation units are solar and wind farms at the scale of 100s
to 1000s MW. Such units, because of their stochastic nature, introduce new
complexity and uncertainty to the grid. Throughout this paper, some results
from the recent planning study of integration of 1,000 MW offshore wind farm
into the U.S. Eastern Interconnection transmission system are shown.
