dissenting.
The granting or the denial of a plea of intervention before the Public Utilities Commission (PUC) is a discretionary act. Mandamus will not lie to compel the performance of a discretionary act. Thus, I would not withdraw the court’s prior opinion which denied the Attorney General’s petition for writ of mandamus and I would overrule the motion for rehearing.
Mandamus is an extraordinary writ which should be used only when there has been an abuse of discretion or a violation of a clear right possessed by the relator and when there is no other adequate remedy at law. State v. Walker, 679 S.W.2d 484, 485 (Tex.1984); Pat Walker & Co. v. Johnson, 623 S.W.2d 306, 308 (Tex.1981); Neville v. Brewster, 352 S.W.2d 449, 452 (Tex.1961). Since none of the prerequisites for the issuance of the writ are present here, mandamus does not lie.
The Attorney General’s office is one of limited powers. The Attorney General may act only if he has constitutional or statutory authority to do so. Day Land & Cattle Co. v. State, 68 Tex. 526, 4 S.W. 865, 867 (1887). The Texas Constitution provides in part:
The Attorney General ... shall represent the State in all suits and pleas in the Supreme Court of the State in which the State may be a party ... 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 ... tolls ... not authorized by law. He shall ... give legal advice in writing to the Governor and other executive officers, when requested by them, and perform such other duties as may be required by law.
Tex. Const, art. IV, § 22 (emphasis added). As is readily apparent, Article IV, § 22 allows the Attorney General to take action “in the courts.” The PUC is not a court, nor is it a functional equivalent of a court.
The powers conferred by the constitution are exclusive and except in a manner authorized by the constitution, these powers cannot be enlarged or restricted. Garcia v. Laughlin, 155 Tex. 261, 285 S.W.2d 191, 194 (1955). When we are called upon to interpret the Constitution, we are “not authorized to thwart the will of the people by reading into the Constitution language not contained therein, or by construing it differently from its plain meaning.” Cramer v. Sheppard, 140 Tex. 271, 167 S.W.2d 147, 154 (1942).
Almost all of the powers granted to the Attorney General have one thing in common — they yoke the Attorney General on the side of the State as its counsel. “The attorney general shall prosecute and defend all actions in which the state is interested before the supreme court and courts of appeals.” Tex. Gov’t Code Ann. § 402.021 (Vernon Pamphlet 1988). The statutes authorizing the Attorney General to represent state agencies in legal matters include, but are not limited to, the following: Tex.Alco.Bev.Code Ann. § 5.15 (Vernon 1978) (the Attorney General is authorized to defend all suits against the Texas Alcoholic Beverage Commission); Tex.Rev. Civ.Stat.Ann. Title HOB, § 35.203 (Vernon *221Pamphlet 1988) (the Attorney General represents the Board of Trustees of the Teacher Retirement System in all litigation); Tex.Rev.Civ.Stat.Ann. art. 3271a, § 23(c) (Vernon Supp.1989) (the Attorney General is authorized to act as legal advisor to the State Board of Registration for Professional Engineers). Nowhere do these grants of power arm the Attorney General with authority to sue the State or any of its agencies.1 Hill v. Lower Colorado River Auth., 568 S.W.2d 473, 480 (Tex.Civ.App.—Austin 1978, writ ref'd n.r.e.).
The fixing or revision of public utility rates is a legislative function. State v. Southwestern Bell Tel. Co., 526 S.W.2d 526, 529-30 (Tex.1975). The Texas Legislature delegated this function to the PUC and enacted the Public Utility Regulatory Act (PURA), a comprehensive scheme for the regulation of public utilities and the protection of various competing interests. Tex.Rev.Civ.Stat.Ann. art. 1446c, § 2 (Vernon Supp.1989). The PURA was enacted “to protect the public interest inherent in the rates and services of public utilities.” Id. In order to ensure that the public interest would be adequately presented to the PUC, the Legislature mandated both a General Counsel and an Office of Public Utility Counsel. The statutory duties of the PUC’s General Counsel include:
... protection and representation of the public interest and coordination and direction of the preparation and presentation of evidence from the commission staff in all cases before the commission as necessary to effect the objectives and purposes stated in this Act and ensure protection of the public interest.
Id. § 8(c)(7). Representation of the interests of residential and small commercial consumers is the function of the Office of Public Utility Counsel. Id. § 15A. Thus, the Attorney General is not a roving ombudsman with the power to intervene in utility rate cases at will, nor does he have the power to substitute his view for that of the PUC. Even if he did have such powers, there is nothing in the record to show that the Attorney General was requested by any state agency to intervene on its behalf in these rate cases. The right to intervene in agency adjudications is usually controlled by agency enabling acts and agency rules. R. Pierce, Jr., S. Shapiro & P. Ver-kuil, Administrative Law and Process § 5.5 (1985).
Generally, administrative agencies have discretionary power to permit or deny petitions for intervention in administrative agency proceedings. Railroad Comm’n of Texas v. Ennis Transp. Co., 695 S.W.2d 706, 710 (Tex.App.—Austin 1985, writ ref’d n.r.e.); 1 F. Cooper, State Administrative Law 325 (1965). Since the PUC had discretion to allow the Attorney General to intervene in these cases, the Attorney General cannot argue that the denial was an abuse of discretion, nor can he argue that he did not have an adequate remedy by appeal. The Attorney General is free to appeal the PUC’s order denying intervention as the parties did in Ennis.
Furthermore, the court’s reliance on Southwestern Bell is misplaced. This case is distinguishable on its facts. There was no PUC or other equivalent regulatory agency in existence when Southwestern Bell was decided.2 In Southwestern Bell, the utility company unilaterally announced an increase in intrastate long distance telephone rates and the Attorney General sought to temporarily enjoin the effectuation of these rates until a full hearing could be held. He argued that the action by the utility company was the equivalent of “demanding or collecting” a rate “not autho*222rized by law.” See Tex. Const, art. IV, § 22. We held that under the “toll” provision, the Attorney General had the constitutional authority to seek injunctive relief. In reaching its conclusion, the court reasoned as follows:
[I]t is held that in the absence of rate regulation by some authorized body, state or municipal, the telephone company may prescribe and apply its own rates, subject to the dictates of reasonableness and justice [citations omitted]. This legal obligation upon the telephone company — that of not exacting exorbitant or unreasonable charges for its services — would be meaningless if there were not judicial redress for its violation.
Southwestern Bell, 526 S.W.2d at 529 (emphasis added).
Our holding in Southwestern Bell stands for the proposition that in absence of state regulation, the Attorney General may resort to the courts to oppose a rate increase not authorized by law. We had no occasion to consider in that case whether the Attorney General would have the right, in the presence of state regulation, to intervene in the regulatory process itself in order to challenge a request for a rate increase.
In the case now before us, several utility companies filed requests for rate increases with the PUC. It is erroneous to conclude, as the court has done, that the act of filing for a rate increase before the PUC is tantamount to the utility company demanding an unlawful rate, thereby providing the predicate for intervention by the Attorney General into the rate process. This is an unjustified and illogical extension of our holding in Southwestern Bell.
The PURA prohibits a utility from making any unauthorized changes in its rates. Tex.Rev.Civ.Stat.Ann. art. 1446c, § 43 (Vernon Supp.1989). In the event that the utility should increase rates without authorization, the Attorney General may institute appropriate court proceedings to enjoin such action and impose statutory penalties. Id. §§ 71, 72. The enforcement provisions clearly recognize the right and duty of the Attorney General to “prevent the exercise by a corporation of a power not conferred by law.” Southwestern Bell, 526 S.W.2d at 531. On the other hand, when the utility properly submits itself to the regulatory authority, the Attorney General has no constitutional or statutory role in the regulatory process. If the Legislature had intended the Attorney General to have a role in protecting the public interest in the regulatory process itself, it would have so provided. Cf Tex. Ins.Code Ann. art. 1.09-l(b) (Vernon Supp. 1989) (Attorney General authorized to intervene in the public interest in insurance rate hearings). However, in failing to provide for a role for the Attorney General, the PURA does not in any way detract from the Attorney General’s power to oppose a demand or collection of an unauthorized rate. Tex. Const, art. IV, § 22; see also Tex. Gov’t Code Ann. §§ 402.021, 402.-023(b) (Vernon Pamphlet 1988).
In summary, the Attorney General has no constitutional or statutory right to intervene in these rate cases without the consent of the PUC. The court ignores the plain meaning of the words used in the constitution and prior pronouncements of this court, e.g., Day Land & Cattle Co. and Laughlin, to reach this result. Furthermore, none of the prerequisites for the issuance of a writ of mandamus are present here. For these reasons I dissent.
. But see Public Util. Comm’n of Texas v. Cofer, 754 S.W.2d 121 (1988). We should not compound a problem created by the Legislature which passed legislation that allows the PUC and the State Purchasing and General Services Commission to be represented by the Attorney General, even when they occupy opposite sides of the docket. Hopefully, the Legislature will correct this problem.
. As the court noted in Southwestern Bell, 526 S.W.2d at 528 n. 1, House Bill 819 of the 64th Texas Legislature created the PUC, under which Southwestern Bell, as well as other utilities, became statutorily regulated. The regulatory commission did not, however, assume its duties until January 1, 1976, and its jurisdiction over rates of public utilities was postponed until September 1, 1976.