Utility Plant (Tables)

12 Months Ended

Dec. 31, 2012

Schedule of Net Utility Plant

Net utility plant as of December 31, 2012 and 2011 was as follows (thousands of dollars):

December 31,	2012			2011
Gas plant:
Storage	$	20,503		$	20,496
Transmission		301,505			295,103
Distribution		4,224,560			4,048,078
General		310,936			291,639
Other		161,996			155,734
		5,019,500			4,811,050
Less: accumulated depreciation		(1,750,795	)		(1,638,091	)
Acquisition adjustments, net		911			1,091
Construction work in progress		74,178			44,894
Net utility plant	$	3,343,794		$	3,218,944

Schedule of Depreciation and Amortization Expense

Depreciation and amortization expense on gas plant was as follows (thousands of dollars):

	2012		2011		2010
Depreciation and amortization expense	$	182,612	$	172,712	$	167,050

Schedule of Rental Payments and Current Term Expiration Dates

The table below presents the rental payments and the current term expiration dates, although both leases have optional renewal terms available.

	2013		2014		2015		2016		2017
(In thousands)
Corporate headquarters (expires in 2017)	$	2,140	$	2,190	$	2,270	$	2,343	$	1,194
Phoenix administrative offices (expires in 2014)		1,446		243		—		—		—

Schedule of Rental Payments for Operating Leases

The table below presents Southwest rental payments and NPL lease payments that are included in operating expenses for all operating leases (in thousands):

	2012		2011		2010
Southwest Gas	$	7,762	$	7,812	$	7,585
NPL		24,054		19,017		11,780
Consolidated rental payments/lease expense	$	31,816	$	26,829	$	19,365

Schedule of Future Minimum Lease Payments for Operating Leases

The following is a schedule of future minimum lease payments for significant non-cancelable operating leases (with initial or remaining terms in excess of one year) as of December 31, 2012 (thousands of dollars):

Year Ending December 31,
2013	$	6,757
2014		4,304
2015		3,181
2016		2,510
2017		1,238
Thereafter		61
Total minimum lease payments	$	18,051