INCOME TAXES

Income tax expense for interim periods is based on the estimated annual effective tax rate, which includes regulatory flow-through adjustments, tax credits, and other items, applied to the Company’s year-to-date, pre-tax income. The significant differences between the U.S. Federal statutory rate and PGE’s effective tax rate for financial reporting purposes are reflected in the following table:



	Three Months Ended March 31,
	2019		2018
Federal statutory tax rate	21.0	%	21.0	%
Federal tax credits^*	(12.7	)	(18.0	)
State and local taxes, net of federal tax benefit	6.5		6.5
Flow through depreciation and cost basis differences	1.3		1.0
Excess deferred tax amortization	(3.7	)	—
Other	0.7		0.6
Effective tax rate	13.1	%	11.1	%

* Federal tax credits consists of production tax credits (PTCs) earned from Company-owned wind-powered generating facilities. PTCs are earned based on a per-kilowatt hour rate and, as a result, the annual amount of PTCs earned will vary based on weather conditions and availability of the facilities. PTCs are generated for 10 years from the in-service dates of the corresponding facilities. PGE’s PTC generation ends at various dates through 2024.

On February 14, 2018, the FASB issued ASU 2018-02 that allows entities subject to FASB requirements to reclassify stranded tax effects resulting from the TCJA from accumulated other comprehensive income (AOCI) to retained earnings. Stranded tax effects are the result of certain items that were recorded in AOCI, net of tax using a historical 35% federal tax rate, and the removal of those items from AOCI using the current 21% tax rate. Pursuant to ASU 2018-02, PGE reclassified $2 million of stranded tax effects from Accumulated other comprehensive loss to Retained earnings for the period ended March 31, 2019.

Carryforwards

Federal tax credit carryforwards as of March 31, 2019 and December 31, 2018 were $59 million and $52 million, respectively. These credits consist of PTCs, which will expire at various dates through 2039. PGE believes that it is more likely than not that its deferred income tax assets as of March 31, 2019 will be realized; accordingly, no valuation allowance has been recorded. As of March 31, 2019, and December 31, 2018, PGE had no unrecognized tax benefits.