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The regional transmission organizations (RTOS), independent system operators (ISOs), and utilities in the United States are coordinating interregional studies and planning their systems to facilitate wind plant deployment and to meet the ever-changing requirements of renewable energy standards. Individual states have passed renewable energy standards (RESs), set goals, and implemented other legislative and public utility commission regulations that require transmission to be built to deliver the renewable energy. Renewable energy grew significantly in the years 2006-2009, and changes, such as California's 33% renewable energy requirement and Indiana's renewable energy goal, continue to be made. RTO, ISO, and utility developments are reflected in modifications that have been made to the wholesale markets, operating practices, planning procedures, and transmission tariffs. Figure 1 shows the footprint of the ten North American RTOs and ISOs and includes the Western Electricity Coordinating Council (WECC) as well.