Southwest Power Pool is a group of 50 members serving more than four million customers acrosseight states of the Eastern Interconnection. Membership is comprised of investor-owned utilities,municipal systems, generation and transmission cooperatives, state authorities, wholesalegenerators, power marketers, and independent transmission companies. SPP was a foundingmember of the North American Electric Reliability Corporation in 1968, and was designated bythe Federal Energy Regulatory Commission as a Regional Transmission Organization in 2004 and aRegional Entity in 2007. Since 1998, SPP has provided independent security coordination and tariffadministration, pursuant to a FERC-approved Tariff, across its service area with over 40,000 milesof transmission lines and over 50,000 megawatts of capacity resources. Member since 2005.