In Texas Association of Business v. Air Control Board, 852 S.W.2d 440, 36 Tex. Sup. Ct. J. 607 (Tex. 1993), this Court stated: Subject matter jurisdiction is essential to the authority of a court to decide a case. Standing is implicit in the concept of subject matter jurisdiction. The standing requirement stems from two limitations on subject matter jurisdiction: the separation of powers doctrine and, in Texas, the open courts provision. Subject matter jurisdiction is never presumed and cannot be waived. . . . Because standing is a constitutional prerequisite to maintaining a suit under both federal and Texas law, we look to the more extensive jurisprudential experience of the federal courts on this subject for any guidance it may yield. . . . We therefore hold that standing, as a component of subject matter jurisdiction, cannot be waived in this or any other case and may be raised for the first time on appeal by the parties or by the court. Id. at 443-46.