Tex. Util. Code § 39.409

An electric utility subject to this subchapter is entitled to recover, as provided by this section, all reasonable and necessary expenditures made or incurred before September 1, 2001, to comply with the provisions of this chapter. Not later than December 1, 2001, each electric utility subject to this subchapter may file with the commission an application for recovery detailing the amounts spent or incurred. After notice and hearing, the commission shall review the amounts and, if found to be reasonable and necessary, approve a transition to competition retail rate rider mechanism for the recovery of the approved transition to competition costs. A rate rider implemented to recover approved transition to competition costs shall expire not later than December 31, 2006.