PROPERTY, PLANT AND EQUIPMENT AND CONSTRUCTION-IN-PROCESS (Tables)

12 Months Ended

Dec. 31, 2024

The other assets are depreciated using the straight-line method over the following estimated useful lives of the assets:


	Years
Buildings	25
Leasehold improvements	15	-	30
Machinery and equipment — manufacturing and drilling	5	-	10
Machinery and equipment — computers	3	-	5
Energy storage equipment	15	-	20
Solar facility equipment	30
Office equipment — furniture and fixtures	5	-	15
Office equipment — other	5	-	10
Vehicles	5	-	7

Property, plant and equipment, net, consist of the following:


	December 31,
	2024		2023
	(Dollars in thousands)
Land owned by the Company where the geothermal resource is located	$	51,500		$	47,612
Leasehold improvements	12,746			12,588
Machinery and equipment	389,252			341,931
Land, buildings and office equipment	145,272			127,970
Vehicles	20,159			17,097
Energy storage equipment	324,065			158,604
Solar facility equipment	97,502			59,214
Geothermal and recovered energy generation power plants, including geothermal wells and exploration and resource development costs:
United States of America, net of cash grants	3,585,209			3,191,505
Foreign countries	919,680			868,289
Asset retirement cost	59,831			59,123
Total cost of property, plant and equipment	5,605,216			4,883,933
Less accumulated depreciation	(2,103,330)			(1,884,984)
Property, plant and equipment, net	$	3,501,886		$	2,998,949

Construction-in-process consists of the following:


	December 31,
	2024			2023
	(Dollars in thousands)
Projects under exploration and development:
Up-front bonus costs		$	5,331		$	5,335
Exploration and development costs		187,669			156,438
Interest capitalized		703			703
Total projects under exploration and development		193,703			162,476
Projects under construction:
Up-front bonus costs		11,031			11,156
Drilling and construction costs		529,773			618,416
Interest capitalized		21,082			22,919
Total projects under construction		561,886			652,491
Total projects under exploration and development and construction		$	755,589		$	814,967


	Projects under exploration and development
	Up-front Bonus Costs		Exploration and Development Costs			Interest Capitalized			Total
	(Dollars in thousands)
Balance at December 31, 2021	$	5,335		$	44,664		$	703		$	50,702
Cost incurred during the year	—			44,566			—			44,566


Balance at December 31, 2022	5,335			89,230			703			95,268
Cost incurred during the year	—			70,667			—			70,667
Write-off of unsuccessful exploration costs	—			(3,459)			—			(3,459)

Balance at December 31, 2023	5,335			156,438			703			162,476
Cost incurred during the year	—			36,339			—			36,339
Write off of unsuccessful exploration costs	(4)			(1,967)			—			(1,971)
Transfer of projects under exploration and development to projects under construction	—			(3,141)			—			(3,141)
Balance at December 31, 2024	$	5,331		$	187,669		$	703		$	193,703

Projects under construction

Up-front Bonus
Costs

Drilling and
Construction
Costs

Interest
Capitalized

Total

(Dollars in thousands)


Balance at December 31, 2021	$	39,156	$	611,553	$	20,072	$	670,781
Cost incurred during the year	—		489,953		5,573		495,526




Transfer of completed projects to property, plant and equipment	(28,000)		(340,377)		—		(368,377)
Balance at December 31, 2022	11,156		761,129		25,645		797,930
Cost incurred during the year	—		473,422		15,181		488,603
Cost write-off	—		(993)		—		(993)


Transfer of completed projects to property, plant and equipment	—		(615,142)		(17,907)		(633,049)
Balance at December 31, 2023	11,156		618,416		22,919		652,491
Cost incurred during the year	—		367,674		12,212		379,886
Cost write off	—		(1,958)		—		(1,958)
Transfer of projects under exploration and development to projects under construction	—		3,141		—		3,141
Transfer of completed projects to property, plant and equipment	(125)		(457,500)		(14,049)		(471,674)
Balance at December 31, 2024	$	11,031	$	529,773	$	21,082	$	561,886

Below are the significant unobservable inputs included in the valuation as of the year ended December 31, 2022.



Significant Unobservable Inputs:
Average generation capacity (MW)	7
Electricity price escalation (%)	2.2	%
Cost long-term growth rate	2.2	%
Average realized electricity price ($/MW)	92.2