WECC began in 1967 as the Western Systems Coordinating Council (WSCC), a group of 40 power systems with a common goal of providing reliable power to the public whom they served. WSCC was staffed by various utilities assigned to work for the group until 1994, when WSCC incorporated and gained its own employees and board of trustees.

In 1996, a series of significant, systemwide disturbances led to the creation of the Reliability Management System, with members voluntarily accepting reliability standards, compliance, and penalties. In 2002, by the merger of three regional transmission associations—WSCC, the Western Regional Transmission Association, and the Southwest Regional Transmission Association—WECC was officially formed.

In 2005, Congress passed the Energy Policy Act. Section 215 of this act called for mandatory, enforceable reliability standards for all users, owners, and operators of the Bulk Power System (BPS). To develop these standards, an Electric Reliability Organization (ERO) was established. This directive also allowed for the ERO to delegate its enforcement responsibilities to a regional entity, allowing WECC to adopt this role.

To allow for the development and practice of the regional reliability standards, WECC formed its compliance department, effectively tripling its staff. In 2007, WECC was designated as the Regional Entity for the Western Interconnection with the authority to create, monitor, and enforce reliability standards. By 2014, WECC had divested its Reliability Coordinator and Interchange Authority functions.

Today, with over 140 employees, WECC exists as a 501(c)(4) social welfare organization, serving the public interest, focusing on mitigating risks to the reliability and security of the BPS in the Western Interconnection with an impartial and unbiased voice.