Const 1963, art 6, § 28 also applies, and provides that a final agency order must be authorized by law and supported by competent, material, and substantial evidence on the whole record. This Court gives due deference to the PSC'S administrative expertise and will not substitute its judgment for that of the PSC. Yankoviak v Public Service Comm, 349 Mich. 641, 648; 85 N.W.2d 75 (1975); Building Owners Managers Ass'n of Metropolitan Detroit v Public Service Comm, 131 Mich. App. 504, 517; 346 N.W.2d 581 (1984), aff'd 424 Mich. 494; 383 N.W.2d 72 (1986). The PSC is a creature of the Legislature, and all of its authority must be found in statutory enactments.
MCL 462.26; MSA 22.45; City of Lansing v Public Service Comm, 330 Mich. 608; 48 N.W.2d 133 (1951); Attorney General v Public Service Comm, 161 Mich. App. 506, 515; 411 N.W.2d 469 (1987), lv den 429 Mich. 879 (1987). A reviewing court gives due deference to the PSC'S administrative expertise and is not to substitute its judgment for that of the PSC. Yankoviak v Public Service Comm, 349 Mich. 641, 648; 85 N.W.2d 75 (1957); Building Owners Managers Ass'n of Metropolitan Detroit v Public Service Comm, 131 Mich. App. 504, 517; 346 N.W.2d 581 (1984), aff'd 424 Mich. 494; 383 N.W.2d 72 (1986). But this does not mean that courts abandon or delegate their responsibility to interpret legislative intent.
The PSC's ratemaking process involved a balancing of the interests of Peninsular and its customers. Building Owners Managers Ass'n of Metropolitan Detroit v Public Service Comm, 424 Mich. 494, 510; 383 N.W.2d 72 (1986); Detroit v Michigan Public Service Comm, supra at 716; ABATE v PSC, 208 Mich. App. 248, 267; 527 N.W.2d 533 (1984). The financial solvency of Peninsular was a legitimate factor for the PSC to consider.
See Attorney General v Public Service Comm, 165 Mich. App. 230, 235; 418 N.W.2d 660 (1987). A reviewing court gives due deference to the PSC's administrative expertise and is not to substitute its judgment for that of the PSC. Yankoviak v Public Service Comm, 349 Mich. 641, 648; 85 N.W.2d 75 (1975); Building Owners Managers Ass'n ofMetropolitan Detroit v Public Service Comm, 131 Mich. App. 504, 517; 346 N.W.2d 581 (1984), aff'd 424 Mich. 494 (1986). Both ABATE and the Attorney General argue that the PSC's orders must be reversed because the PSC approved Consumers' application, authorizing an increase in rates, without providing notice and an opportunity for interested parties to be heard as required by § 6a.
Mullane v Central Hanover Bank Trust Co, 339 US 306; 70 S Ct 652; 94 L Ed 865 (1950), involved the sufficiency of the process that was given in that case when the recipients had a vested right in trust property. Building Owners Managers Ass'n v PSC, 424 Mich 494, 501-502; 383 NW2d 72 (1986), which did involve the sufficiency of notice given about a rate increase, reached no decision regarding whether the public has a constitutional right to notice of PSC rate increases or to participation in rate hearings. In contrast, in Attorney General v PSC, supra, 249 Mich App at 433-437, this Court discussed the appellants' argument that the PSC's dismissal of pending power supply cost recovery (PSCR) proceedings illegally cut off Detroit Edison's customers' rights to refunds related to PSCR over-recoveries and certain cost disallowances.
A refund of monies paid pursuant to an invalid rate order will be mandated if the order is subsequently found to be unreasonable. Bldg Owners Managers Ass'n v PSC, 424 Mich. 494, 508; 383 N.W.2d 72 (1986). The bar against retroactive ratemaking did not preclude the PSC from allowing Ameritech to bill for a discount that was imposed by an invalid order.
A reviewing court gives due deference to the MPSC's administrative expertise, and is not to substitute its judgment for that of the MPSC. Yankoviak v. Public Service Comm, 349 Mich. 641, 648; 85 N.W.2d 75 (1957); Building Owners Managers Ass'n of Metropolitan Detroit v. Public Service Comm, 131 Mich. App. 504, 517; 346 N.W.2d 581 (1984), aff'd 424 Mich. 494; 383 N.W.2d 72 (1986). ABATE has not demonstrated that the rates established in the MPSC's March 31, 1993 order are unjust, unlawful or unreasonable.
Appellants, the Association of Businesses Advocating Tariff Equity (ABATE) and the Attorney General, argue that the PSC was without authority to apply the prudent investment test. But the test is well recognized and appellants' argument is contrary to the principle that the PSC is not bound by any particular method or formula in exercising its legislative function to determine just and reasonable rates. Building Owners Managers Ass'n of Metropolitan Detroit v Public Service Comm, 424 Mich. 494, 510; 383 N.W.2d 72 (1986); Michigan Bell Telephone Co v Public Service Comm, 332 Mich. 7, 36-37; 50 N.W.2d 826 (1952) [ Michigan Bell I]. Appellants have failed to show that using the prudent investment test was unlawful or unreasonable. MCL 462.26(8); MSA 22.45(8); CMS Energy Corp v Attorney General, 190 Mich. App. 220, 228; 475 N.W.2d 451 (1991).
See Attorney General v Public Service Comm, 165 Mich. App. 230, 235; 418 N.W.2d 660 (1987). A reviewing court gives due deference to the PSC's administrative expertise and is not to substitute its judgment for that of the PSC. Yankoviak v Public Service Comm, 349 Mich. 641, 648; 85 N.W.2d 75 (1975); Building Owners Managers Ass'n of Metropolitan Detroit v Public Service Comm, 131 Mich. App. 504, 517; 346 N.W.2d 581 (1984), aff'd 424 Mich. 494; 383 N.W.2d 72 (1986). Section 2 of Act 69, MCL 460.502; MSA 22.142, reads:
We disagree. Retroactive ratemaking is prohibited by law. Building Owners Managers Ass'n v Public Service Comm, 424 Mich. 494; 383 N.W.2d 72 (1986); Michigan Bell Telephone Co v Public Service Comm, 315 Mich. 533; 24 N.W.2d 200 (1946). However, the commission neither approved Consumers Power's noneconomic burning of Union Carbide oil at Karn nor held that its cost was reasonable.