PROPERTY, PLANT AND EQUIPMENT (Notes)

12 Months Ended

Dec. 31, 2021

The following table sets forth our property, plant and equipment by property type, for the periods indicated:


	December 31,		December 31,
	2021		2020
	(Thousands of dollars)
Natural gas distribution pipelines and related equipment	$	5,836,066	$	5,517,488
Natural gas transmission pipelines and related equipment	624,528		586,360
General plant and other	712,659		657,037
Construction work in process	101,015		77,718
Property, plant and equipment	7,274,268		6,838,603
Accumulated depreciation and amortization	(2,083,433)		(1,971,546)
Net property, plant and equipment	$	5,190,835	$	4,867,057

We compute depreciation expense by applying composite, straight-line rates of approximately 2.5 percent to 3.5 percent that were approved by various regulatory authorities.

We recorded capitalized interest of $4.2 million, $4.2 million and $4.6 million for the years ended December 31, 2021, 2020 and 2019, respectively. We incurred liabilities for construction work in process that had not been paid at December 31, 2021, 2020 and 2019 of $25.6 million, $24.3 million and $20.9 million, respectively. Such amounts are not included in capital expenditures or in the change of working capital items on our Consolidated Statements of Cash Flows.