TCAP was originally two separate non-profit city coalitions, the Cities Aggregation Power Project (“CAPP”) and the South Texas Aggregation Project (“STAP”). These twin political subdivision corporations were formed by cities in 2001 to leverage the best prices under the electric deregulation law, which was then taking effect. CAPP and STAP merged in 2011  to form the Texas Coalition for Affordable Power.

TCAP is the largest coalition of its type in the state. Members that comprise TCAP purchase in excess of 1.3 billion kilowatt-hours of electricity every year.

Over the years, member cities have saved as much as 20 percent off the average energy rate that they would have paid without TCAP, often amounting to tens of thousands of dollars that can be used for other city services vital to residents.TCAP members also enjoy price stability, excellent customer service, and legislative and regulatory advocacy.

TCAP membership is open to all Texas cities (and other political subdivisions such as water districts) that purchase electricity in the deregulated market. It is run entirely by its members. The voluntary 15-person TCAP board of directors is comprised of city officials and executives who meet on a regular basis.