Tex. Utilities Code § 39.102

(a) Each retail customer in this state, except retail customers of electric cooperatives and municipally owned utilities that have not opted for customer choice, shall have customer choice on and after January 1, 2002.

(b) The affiliated retail electric provider of the electric utility serving a retail customer on December 31, 2001, may continue to serve that customer until the customer chooses service from a different retail electric provider, an electric cooperative offering customer choice, or a municipally owned utility offering customer choice.

(c) An electric utility that has in effect a systemwide freeze for residential and commercial customers in effect September 1, 1997, extending beyond December 31, 2001, that has been found by a regulatory authority to be in the public interest is not subject to this chapter. At the expiration of the utility's freeze period, the utility shall be subject to this chapter and, at that time, has no claim for stranded cost recovery.

(d) The commission shall oversee the compliance with this chapter by electric utilities that were not subject to this chapter before September 1, 2003, and in so doing shall establish schedules and procedures and require commission approvals as it deems necessary to achieve the objectives of this chapter. This subsection does not apply to an electric utility to which Subsection (c) applies.

(e) In establishing a schedule under Subsection (d), the commission shall consider:

(1) the effect of customer choice on the reliability of service provided by the electric utility;

(2) whether the electric utility's service area is located in more than one power region;

(3) whether any applicable power region has been certified as a qualifying power region under Section 39.152(a);

(4) whether other electric utilities in the power region offer retail customer choice; and

(5) any other relevant factor.