Texas Utilities Code - UTIL § 39.105. Limitation on Sale of Electricity

(a) After January 1, 2002, a transmission and distribution utility may not sell electricity or otherwise participate in the market for electricity except for the purpose of buying electricity to serve its own needs.

(b) A person or retail electric utility may not provide, furnish, or make available electric service at retail within the certificated service area of an electric cooperative that has not adopted customer choice or a municipally owned utility that has not adopted customer choice.  However, this subsection does not prohibit the provision of electric service in multiply certificated service areas to customers of any other retail electric utility.