The need to accommodate peak demand conditions is no longer the sole driver of transmission capacity requirements. the need for extensive scrutiny on an individual basis. With such a framework in place, the regulator's role can shift from detailed investment evaluation to ensuring that commercial incentives, market design, and planning process are fit for purpose in view of technological advancements. system operator (ISO), which will plan and operate but not own the transmission network infrastructure. The ISO would not have the conflicts of interest that the current TSO as an entity combining transmission ownership and operation potentially has, and at the same time it would be in a better position to evaluate the efficiency of transmission investment than the regulator. If this institutional setup is accompanied by a transparent and efficient process for transmission planning then there is scope for From TSO to ISO Paradigm As a result of the aforementioned concerns, Great Britain is moving toward the introduction of an independent (a) (b) (c) figure 12. An optimal first-stage network design under proactive for (a) scenario 1, (b) scenario 4, and (c) min-max proactive. The color code is the same as in Figure 9. 74 ieee power & energy magazine july/august 2015