An interesting article in Intelligent Utility reviews a number of the research and development (R&D) priorities facing transmission and renewable power development. One of those priorities is maximizing the capacity and efficiency of the existing grid. Given the levels of congestion already occurring in many parts of the grid, it will be impossible to add the renewable energy we need (and in some places require through renewable portfolio standards) without expanding transmission capacity.
To address this, researchers are reviewing new technologies to transmit power over existing lines and rights of way, as well as new processes to provide more real time data to grid managers. The North American SynchroPhasor Initiative keeps an updated list of such projects that you can search here.