PECO Energy Company v. Commonwealth, 591 Pa. 405, 919 A.2d 188 (2007), involved a review of the way that tax due to the Commonwealth was computed under the Public Utility Realty Tax Act (PURTA) following the deregulation of the electric market effectuated by the Electricity Generation Customer Choice and Competition Act (Competition Act), 66 Pa. C.S. 2801-2812. At issue in PECO was the word "cost" as used in PURTA to determine the cost of PECO's utility realty. PECO alleged that the plain language of PURTA indicated that the cost to be used was the cost as shown by the books of account of a public utility. The Commonwealth disagreed, asserting that "cost" in accounting terms meant the original cost. In reversing our decision adopting the Commonwealth's interpretation, the Supreme Court concluded that the language of PURTA was clear and that "cost" was shown on the books after the utility wrote down the cost of electric generation property as required by generally accepted accounting principles, not original cost. In PECO, the Supreme Court reversed our Court's decision, which found that the Competition Act "had no effect on the value of its utility realty for tax purposes." PECO Energy Company v. Commonwealth, 828 A.2d 497, 502 (Pa. Cmwlth. 2003), adopted as opinion of en banc court, 848 A.2d 1099 (2004), rev'd 591 Pa. 405, 919 A.2d 188 (2007). The Court reached this decision despite generally accepted accounting practices requiring that the "cost . . . as shown on the books" of PECO's realty must be written down because of the Competition Act. PECO, 591 Pa. at 411, 919 A.2d at 191 (quoting Section 3 of the Act commonly known as the Public Utility Realty Tax Act 1 (PURTA), 72 P.S. 8101-A(4)). The Supreme Court, in reversing this Court, held that the plain language of PURTA needed to be applied and that the decline in value of the realty was a legally significant consequence of the General Assembly's enactment of the Competition Act, which could not be ignored. The Supreme Court concluded that "it is not within this Court's power to change the plain language of the statute." PECO, 591 Pa. at 413, 919 A.2d at 193.