Western Interconnection is the geographic area comprising the synchronized electrical grid in western North America, which includes parts of Montana, Nebraska, New Mexico, South Dakota, Texas, Wyoming and Mexico, as well as all of Arizona, California, Colorado, Idaho, Nevada, Oregon, Utah, Utah, Created in 2002 by the Western Systems Coordinating Council (WSCC) and two regional transmission associations, THE WECC comprises the entire Western interconnection and covers more than 1.8 million square kilometres. WECC members, representing all segments of the electrical industry within the Western interconnection, provide electricity to 71 million people in 14 western states, two Canadian provinces and part of a Mexican state. A balancing authority (BA) or control zone, usually composed of large and small transmission owners, is the responsible unit, which compares loads with resources within the system, maintains planned exchanges between control areas, maintains frequency within reasonable limits and provides sufficient production capacity to maintain operating reserves. Data on the load and resources transmitted by BA to WECC are used to identify areas that could lead to electricity shortages. NERC`s eight regional units include the 48 neighbouring states and parts of Canada and Mexico. WECC`s previous organization, WSCC, was founded in 1967 to facilitate the coordination of the electrical industry in the design and operation of the electrical system in western North America. Similarly, this is the mission of WECC today: data from the four different reporting areas (or NERC sub-regions as shown) enable WECC: Achieve the mission and accomplish four organizational tasks: Due to the different scope and characteristics of the region, WECC members face unique and difficult problems in coordinating the day-to-day operation of interconnected systems and the overall existing and programmed production – since temperature and seasonal phenomena can radically influence electricity generation, needs and resource use, different scenarios are evaluated. Scenarios are divided into classes to determine existing production, variations in production and needs, the status and impact of planned production inflows, and the status and impact of planned transportation projects. Northwest Power Pool Area (NWPP) Rocky Mountain Power Area (RMPA) Arizona-New Mexico-Southern Nevada Power Area (AZ/NM/SNV) California-Mexico Power Area (CA/MX) Source: WECC Regional Planning Project Review, Loads and Resources Working Group, Scenario Needs Analysis for 2015 To study the range of need for a Canada/Pacific Northwest North California Line-October 2007 Red Zone – less than 15% Green Zone Reserve Margin – over 15% White Zone Reserve Margin – 15% Red line reserve margin exactly – fully loaded path in the direction of the green line arrow – partly path in the direction of the green arrow loaded line without arrow – path without proper feed flow – In accordance with the requirement, maintaining operating reserves as defined in the weCC and NERC operating guidelines , wecc conducts a seasonal assessment of the production of reserve margins and transport restrictions between load and resource areas, as well as the likelihood of supplying the load levels expected by: taking into account uncertainties.