8. PROPERTY, PLANT AND EQUIPMENT


	2017			2016			2015
Net book value of property, plant and equipment		382,630			345,679			274,122
Provision for obsolescence of materials and equipment		(1,652	)		(1,380	)		(762	)
Provision for impairment of property, plant and equipment		(26,535	)		(36,285	)		(2,455	)

		354,443			308,014			270,905

Changes in Group’s property, plant and equipment for the years ended December 31, 2017, 2016 and 2015 are as follows:


	Land and buildings			Mineral property, wells and related equipment			Refinery equipment and petrochemical plants			Transportation equipment			Materials and equipment in warehouse			Drilling and work in progress			Exploratory drilling in progress			Furniture, fixtures and installations			Selling equipment			Infrastructure for natural gas distribution			Electric power generation facilities			Other property			Total
Cost		9,084			265,376			42,081			2,160			8,241			45,051			1,781			3,314			5,520			2,722			1,567			5,502			392,399
Accumulated depreciation		3,779			192,170			24,842			1,455			—			—			—			2,817			4,215			1,116			1,171			3,591			235,156

Balances as of December 31, 2014		5,305			73,206			17,239			705			8,241			45,051			1,781			497			1,305			1,606			396			1,911			157,243

Cost
Increases		23			(1,140	)⁽⁴⁾		7			5			7,823			50,139			2,767			36			1			—			—			219			59,880
Translation effect		4,630			155,844			23,707			1,155			4,432			24,005			992			1,865			3,640			—			—			2,633			222,903
Decreases and reclassifications		212			37,986	⁽⁵⁾		3,634			330			(7,018	)		(42,392	)		(1,893	)		388			1,617			209			6			(63	)		(6,984	)⁽³⁾
Accumulated depreciation
Increases		211			22,884	⁽⁴⁾		2,289			218			—			—			—			323			345			68			112			235			26,685
Translation effect		1,934			110,301			14,019			773			—			—			—			1,559			2,361			—			—			1,796			132,743
Decreases and reclassifications		(4	)		(433	)⁽⁵⁾		(12	)		(54	)		—			—			—			—			—			(3	)		—			(2	)		(508	)
Cost		13,949			458,066			69,429			3,650			13,478			76,803			3,647			5,603			10,778			2,931			1,573			8,291			668,198
Accumulated depreciation		5,920			324,922			41,138			2,392			—			—			—			4,699			6,921			1,181			1,283			5,620			394,076

Balances as of December 31, 2015		8,029			133,144	⁽¹⁾		28,291			1,258			13,478			76,803			3,647			904			3,857			1,750			290			2,671			274,122

Cost
Increases		140			3,831	⁽⁴⁾		1			3			6,968			52,610			1,392			25			—			—			2			76			65,048
Translation effect		2,975			104,086			16,601			802			2,494			14,602			626			1,260			2,430			—			—			1,658			147,534
Decreases and reclassifications		1,365			59,645			26,529			1,096			(8,701	)		(91,342	)		(3,687	)		1,201			1,138			260			187			(60	)		(12,369	)⁽³⁾⁽⁶⁾
Accumulated depreciation
Increases		360			40,729	⁽⁴⁾		4,312			414			—			—			—			668			642			75			111			318			47,629
Translation effect		1,257			73,288			9,288			516			—			—			—			1,052			1,558			—			—			1,142			88,101
Decreases and reclassifications		(40	)		(6,937	)		(3	)		(37	)		—			—			—			(18	)		(2	)		45			—			(82	)		(7,074	)⁽⁶⁾
Cost		18,429			625,628			112,560			5,551			14,239			52,673			1,978			8,089			14,346			3,191			1,762			9,965			868,411
Accumulated depreciation		7,497			432,002			54,735			3,285			—			—			—			6,401			9,119			1,301			1,394			6,998			522,732

Balances as of December 31, 2016		10,932			193,626	⁽¹⁾		57,825			2,266			14,239			52,673			1,978			1,688			5,227			1,890			368			2,967			345,679

Cost
Increases		49			(4,370	)⁽⁴⁾		103			66			7,394			47,453			2,207			20			—			—			—			174			53,096
Translation effect		3,028			113,481			19,728			1,032			2,101			8,568			373			1,466			2,744			—			—			1,651			154,172
Decreases and reclassifications		(112	)		40,614			2,284			965			(7,741	)		(49,165	)		(1,687	)		879			1,698			215			(1,762	)⁽⁷⁾		188			(13,624	)⁽³⁾
Accumulated depreciation
Increases		437			54,980	⁽⁴⁾		5,395			602			—			—			—			717			854			80			87			315			63,467
Translation effect		1,303			81,108			9,983			609			—			—			—			1,196			1,684			—			—			1,151			97,034
Decreases and reclassifications		13			(1,756	)		(953	)		16			—			—			—			372			(1	)		—			(1,481	)⁽⁷⁾		(18	)		(3,808	)
Cost		21,394			775,353			134,675			7,614			15,993			59,529			2,871			10,454			18,788			3,406			—			11,978			1,062,055
Accumulated depreciation		9,250			566,334			69,160			4,512			—			—			—			8,686			11,656			1,381			—			8,446			679,425

Balances as of December 31, 2017		12,144			209,019	⁽¹⁾		65,515			3,102			15,993			59,529			2,871	⁽²⁾		1,768			7,132			2,025			—			3,532			382,630

(1)	Includes 10,003, 9,147 and 8,435 of mineral property as of December 31, 2017, 2016 and 2015, respectively.

(2)	As of December 31, 2017, there are 35 exploratory wells in progress. During year ended on such date, 37 wells were drilled, 24 wells were charged to exploratory expense and 15 were transferred to prove properties which are included in the account Mineral property, wells and related equipment.

(3)	Includes 7, 2 and 6 of net book value charged to property, plant and equipment provisions for the years ended December 31, 2017, 2016 and 2015, respectively.

(4)	Includes (4,913), 2,243 and (1,281) corresponding to hydrocarbon wells abandonment costs for the years ended December 31, 2017, 2016 and 2015, respectively.

(5)	Includes (2,671) residual value for the El Orejano area; (226) corresponding to the decrease in participation in the Magallanes area; and (8) corresponding to the decrease in participation in the Puesto Cortadera area.

(6)	Includes reductions for the deconsolidation of subsidiaries of 500, net.

(7)	Incluye 6,722 y 1,790 de valor de origen y depreciación acumulada, respectivamente, correspondientes a la reclasificación de los activos de YPF EE como mantenidos para su disposición.

The Group capitalizes the financial cost as a part of the cost of the assets. For the year ended December 31, 2017, 2016 and 2015, the rate of capitalization has been 11.63%, 13.03% and 12.01%, respectively, and the amount capitalized amounted to 707, 1,234 and 1,003, respectively, for the years mentioned above.

Set forth below is the evolution of the provision for obsolescence of materials and equipment for the years ended December 31, 2017, 2016 and 2015:


	2017			2016			2015
Amount at beginning of year		1,380			762			313
Increase charged to profit/ (loss)		11			428			243
Decreases charged to profit/ (loss)		(45	)		—			—
Amounts incurred due to utilization		(7	)		(2	)		(6	)
Transferencias y otros movimientos		65			—			—
Translation differences		248			192			212

Amount at end of year		1,652			1,380			762

Set forth below is the evolution of the provision for impairment of property, plant and equipment for 2017, 2016 and 2015:


	2017			2016			2015
Amount at beginning of year		36,285			2,455			—
Increase charged to profit/ (loss)⁽¹⁾		—			36,188			2,455
Decrease charged to profit/ (loss)⁽¹⁾		(5,032	)		(1,245	)		—
Depreciation⁽²⁾		(9,955	)		(2,877	)		—
Translation differences		5,237			1,869			—
Deconsolidation of subsidiaries		—			(105	)		—

Amount at end of year		26,535			36,285			2,455

(1)	See Note 2.c).

(2)	Included in “Depreciation of property, plant and equipment” in Note 21.

Set forth below is the cost evolution for the exploratory wells in evaluation stage as of the years ended on December 31, 2017, 2016 and 2015:


	2017			2016			2015
Amount at beginning of year		1,475			1,777			993
Additions pending the determination of proved reserves		758			1,112			1,219
Decreases charged to exploration expenses		(591	)		(700	)		(479	)
Decrease of assets assignment		—			(15	)		(89	)
Reclassifications to mineral property, wells and related equipment with proved reserves		(581	)		(1,004	)		(466	)
Translation difference		175			305			599

Amount at end of year		1,236			1,475			1,777

The following table shows the capitalized cost for exploratory wells for a period greater than a year and the number of projects related as of December 31, 2017.


	Amount		Number of projects		Number of Wells
Between 1 and 5 years		413		3		3