Jointly-Owned Facilities (Tables)

12 Months Ended

Dec. 31, 2017

Jointly Owned Utility Plant, Net Ownership Amount [Abstract]

APS's interests in jointly-owned facilities recorded on the Consolidated Balance Sheets

The following table shows APS’s interests in those jointly-owned facilities recorded on the Consolidated Balance Sheets at December 31, 2017 (dollars in thousands):

	Percent Owned			Plant in Service		Accumulated Depreciation		Construction Work in Progress
Generating facilities:
Palo Verde Units 1 and 3	29.1	%		$	1,872,104	$	1,092,049	$	24,257
Palo Verde Unit 2 (a)	16.8	%		619,263		364,516		14,672
Palo Verde Common	28.0	%	(b)	726,223		262,065		46,577
Palo Verde Sale Leaseback			(a)	351,050		241,405		—
Four Corners Generating Station	63.0	%		1,196,683		568,304		240,514
Cholla common facilities (c)	50.5	%		180,907		69,633		1,091
Transmission facilities:
ANPP 500kV System	34.0	%	(b)	130,767		46,400		684
Navajo Southern System	27.5	%	(b)	85,299		28,915		180
Palo Verde — Yuma 500kV System	18.1	%	(b)	14,765		6,614		486
Four Corners Switchyards	63.2	%	(b)	66,386		12,605		327
Phoenix — Mead System	17.1	%	(b)	39,383		17,600		41
Palo Verde — Rudd 500kV System	50.0	%		97,600		23,884		245
Morgan — Pinnacle Peak System	64.6	%	(b)	117,721		14,569		1
Round Valley System	50.0	%		515		141		—
Palo Verde — Morgan System	90.9	%	(b)	137,887		3,948		94,350
Hassayampa — North Gila System	80.0	%		142,541		6,953		—
Cholla 500kV Switchyard	85.7	%		5,243		1,312		190
Saguaro 500kV Switchyard	60.0	%		20,473		12,574		—
Kyrene — Knox System	50.0	%		578		297		—

(a) See Note 18.

(b) Weighted-average of interests.

(c) PacifiCorp owns Cholla Unit 4 and APS operates the unit for PacifiCorp.  The common facilities at Cholla are jointly-owned.