Tex. Util. Code § 39.310

Transition bonds are not a debt or obligation of the state and are not a charge on its full faith and credit or taxing power. The state pledges, however, for the benefit and protection of financing parties and the electric utility, that it will not take or permit any action that would impair the value of transition property, or, except as permitted by Section 39.307, reduce, alter, or impair the transition charges to be imposed, collected, and remitted to financing parties, until the principal, interest and premium, and any other charges incurred and contracts to be performed in connection with the related transition bonds have been paid and performed in full. Any party issuing transition bonds is authorized to include this pledge in any documentation relating to those bonds.