PROPERTY, PLANT AND ACCUMULATED DEPRECIATION

12 Months Ended

Dec. 31, 2012

Notes To Consolidated Financial Statements [Abstract]

Schedule of Public Utility Property, Plant, and Equipment [Text Block]

4. PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION

Utility property, plant and equipment is recorded at original cost. Original cost includes materials, labor, construction overhead and AFUDC for regulated property. The cost of repairs and maintenance, including planned major maintenance activities, is charged to Operating Expenses as incurred.

The following tables summarize the NU, CL&P, NSTAR Electric, PSNH and WMECO investments in utility property, plant and equipment by asset category:

NU		As of December 31,
(Millions of Dollars)		2012		2011
Distribution - Electric		$	11,438.2	$	6,540.4
Distribution - Natural Gas			2,274.2		1,247.6
Transmission			5,541.1		3,541.9
Generation			1,146.6		1,096.0
Electric and Natural Gas Utility			20,400.1		12,425.9
Other⁽¹⁾			429.3		305.1
Property, Plant and Equipment, Gross			20,829.4		12,731.0
Less: Accumulated Depreciation
	Electric and Natural Gas Utility		(5,065.1)		(3,035.5)
	Other		(171.5)		(120.2)
Total Accumulated Depreciation			(5,236.6)		(3,155.7)
Property, Plant and Equipment, Net			15,592.8		9,575.3
Construction Work in Progress			1,012.2		827.8
Total Property, Plant and Equipment, Net		$	16,605.0	$	10,403.1

(1) These assets represent unregulated property and are primarily comprised of building improvements at RRR and software and equipment at NUSCO as of December 31, 2012 and 2011, and telecommunications equipment at NSTAR Communications, Inc. as of December 31, 2012.

	As of December 31,
	2012								2011
			NSTAR								NSTAR
(Millions of Dollars)	CL&P		Electric		PSNH		WMECO		CL&P		Electric⁽¹⁾		PSNH		WMECO
Distribution	$	4,691.3	$	4,539.9	$	1,520.1	$	724.2	$	4,419.6	$	4,334.4	$	1,451.6	$	704.3
Transmission		2,796.1		1,529.7		599.2		583.7		2,689.1		1,386.9		546.4		297.4
Generation		-		-		1,125.5		21.1		-		-		1,074.8		21.2
Property, Plant and
Equipment, Gross		7,487.4		6,069.6		3,244.8		1,329.0		7,108.7		5,721.3		3,072.8		1,022.9
Less: Accumulated Depreciation		(1,698.1)		(1,540.1)		(954.0)		(252.1)		(1,596.7)		(1,436.0)		(893.6)		(240.5)
Property, Plant and Equipment, Net		5,789.3		4,529.5		2,290.8		1,076.9		5,512.0		4,285.3		2,179.2		782.4
Construction Work in Progress		363.7		205.8		61.7		213.6		315.4		162.0		77.5		295.4
Total Property, Plant and
Equipment, Net	$	6,153.0	$	4,735.3	$	2,352.5	$	1,290.5	$	5,827.4	$	4,447.3	$	2,256.7	$	1,077.8

(1) NSTAR Electric amounts are not included in NU consolidated as of December 31, 2011.

Depreciation of utility assets is calculated on a straight-line basis using composite rates based on the estimated remaining useful lives of the various classes of property (estimated useful life for PSNH distribution). The composite rates are subject to approval by the appropriate state regulatory agency. The composite rates include a cost of removal component, which is collected from customers during the life of the property and is recognized as a regulatory liability. Depreciation rates are applied to property from the time it is placed in service.

Upon retirement from service, the cost of the utility asset is charged to the accumulated provision for depreciation. The actual incurred removal costs are applied against the related regulatory liability.

The depreciation rates for the various classes of utility property, plant and equipment aggregate to composite rates as follows:

(Percent)	2012		2011		2010
NU		2.5		2.6		2.7
CL&P		2.5		2.4		2.7
NSTAR Electric		2.8		3.0		3.0
PSNH		3.0		2.9		2.8
WMECO		3.3		2.9		2.8

The following table summarizes average useful lives of depreciable assets:

	Average Depreciable Life
(Years)	NU		CL&P		NSTAR Electric		PSNH		WMECO
Distribution		42.1		41.8		33.9		33.8		30.2
Transmission		45.3		39.8		46.3		42.1		47.5
Generation		32.7		-		-		32.8		25.0
Other		16.7		-		-		-		-