ON MOTION FOR REHEARING
MAUZY, Justice.The court’s opinion and judgment of May 25, 1988 is withdrawn and the following is substituted therefor.
The issue in this original proceeding is whether the Attorney General, on behalf of state agencies, has the right to intervene in electric utility rate cases before the Public Utility Commission. Central Power & Light Company and Houston Lighting & Power Company petitioned the Public Utility Commission for preferential accounting treatment for costs related to the South Texas Nuclear Project. The Attorney General, representing state agencies as consumers of electricity, sought to intervene in order to oppose the utilities’ petition. The hearings examiners presiding over these rate cases granted the Attorney General’s motions to intervene. However, General Counsel for the Commission appealed the examiners’ order to the Commission itself1 and the Commission issued an order reversing the examiners’ joint order allowing intervention. The Attorney General has now petitioned this court for a writ of manda*219mus to compel the Commission to rescind its order striking his intervention. Because we hold that the Public Utility Commission cannot constitutionally deny the Attorney General’s intervention on behalf of consumer state agencies, we grant the writ of mandamus and order the Commission to vacate its order.
Article IV, section 22 of the Texas Constitution sets forth the duties of the Attorney General as follows:
The Attorney General ... shall represent the State in all suits and pleas in the Supreme Court of the State ... and from time to time, in the name of the State, take such action in the courts as may be proper and necessary to prevent any private corporation from exercising any power or demanding or collecting any species of taxes, tolls, freight or wharf-age not authorized by law. He shall ... perform such other duties as may be required by law.
In State v. Southwestern Bell Telephone Co., 526 S.W.2d 526 (Tex.1975), we recognized that unreasonably high rates were not lawful and held that this constitutional provision confers on the Attorney General the power “to institute and maintain suit in the name of the State” to prevent a utility company from exacting unreasonably high charges. This is exactly what the Attorney General was attempting to do in this case. He was trying “to institute and maintain suit” to prevent a utility company from charging unreasonable rates.
The Commission argues that this constitutional provision only authorizes the Attorney General to take action "in the courts,” and not in an agency. However, a ratemaking proceeding is a “contested case” within the meaning of the Administrative Procedure and Texas Register Act and, as such, is a formal adjudicative proceeding in which the agency performs in a quasi-judicial function. Tex.Rev.Civ.Stat. art. 6252-13a, §§ 3(2), 13. In creating the Public Utility Commission, the legislature effectively shifted the forum of original jurisdiction for challenging a utility’s rates from the district courts to the agency. See Public Utility Regulatory Act, Tex.Rev.Civ. Stat. art. 1446c. Now, a lawsuit to challenge the reasonableness of a utility’s rates can be properly “instituted” only by intervening at the agency level. See Tex.Rev. Civ.Stat. art. 6252-13a, § 19. The Attorney General cannot act “to prevent” unlawfully exorbitant rates unless he can begin by intervening before the agency.
This part of article IV, section 22 first appeared in the 1876 Texas Constitution. At that time, we did not have the proliferation of regulatory agencies that we now have. Even the Railroad Commission was not created until 1891. Tex. Const, art. X, § 2, interp. commentary (Vernon 1955). Many disputes that were once litigated in the courts are now, for all practical purposes, litigated in the agencies. That is where the evidence is heard and the record is made. By the time most such disputes reach the courts, they present themselves in a posture more akin to appellate review. See Tex.Rev.Civ.Stat. art. 6252-13a, § 19(d)(3). We conclude that article IV, section 22 uses the term “courts” in a generic sense to refer to an adjudicative forum. It is implied within the meaning of this constitutional provision that the Attorney General will be able to take action in the adjudicative forum of first jurisdiction regardless of whether the label attached to that forum is “court” or “agency.”
Were we to hold that the Attorney General had no right to intervene before the agency, it would mean that the legislature had obliterated a constitutional grant of power merely by statutorily creating an agency to serve the same function as courts once did in adjudicating such disputes. The legislature cannot by statute abrogate the Attorney General’s constitutional grant of power. Only by constitutional amendment can the legislature alter the constitutional balance of powers; it cannot do so by legislation. No matter what the language of the Public Utility Regulatory Act, it cannot subtract from the powers granted in the constitution.
Furthermore, section 402.023 of the Texas Government Code tracks the language of article IV, section 22, but does not contain any language that could even *220arguably limit the Attorney General to action “in the courts.” Because article IV, section 22 also imposes on the Attorney General the obligation to “perform such other duties as may be required by law,” the more general statutory requirement of section 402.023 becomes a constitutional duty, requiring the Attorney General to act in whatever forum and whatever manner as may be necessary and proper to prevent corporations from exacting unreasonable rates.
We grant the State’s motion for rehearing and grant its petition for writ of mandamus. We order the Public Utility Commission to vacate its order denying intervention and to permit the Attorney General to intervene in these electric rate cases.
GONZALEZ, J., files a dissenting opinion. HECHT, J., files a dissenting opinion in which PHILLIPS, C.J., and COOK, J., join.. We question whether this use of the general counsel’s office comports with its statutory authority. See Tex.Rev.Civ.Stat. art. 1446c, § 8(c). However, this is a matter which we need not now consider.