Property, Plant and Equipment

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Property, plant and equipment consists of the following (in thousands):


	December 31,
	2022		2021
Oil and natural gas properties
Proved	$	1,507,690	1,454,016
Unproved	11,516		12,255
Total oil and natural gas properties	1,519,206		1,466,271
Less accumulated depreciation, depletion and impairment	(1,380,574)		(1,373,217)
Net oil and natural gas properties capitalized costs	138,632		93,054

Land	200		200
Electrical infrastructure	121,819		121,819
Non-oil and natural gas equipment	1,644		1,575
Buildings and structures	3,603		3,603
Financing Leases	1,468		1,384
Total	128,734		128,581
Less accumulated depreciation and amortization	(36,490)		(30,790)
Other property, plant and equipment, net	92,244		97,791
Total property, plant and equipment, net	$	230,876	$	190,845

The average rates used for depreciation and depletion of oil and natural gas properties were $1.18 per Boe in 2022, $0.78 per Boe in 2021 and $5.11 per Boe in 2020.

See Note 9 for discussion of impairment of other property, plant and equipment.

Costs Excluded from Amortization

Costs excluded from amortization were related to unproved properties and were $11.5 million and $12.3 million, at December 31, 2022 and 2021, respectively.

For leases that do not have existing production that would otherwise extend the lease term, the Company estimates that any associated unproved costs will be evaluated and transferred to the amortization base of the full cost pool within a three to five-year period from the original lease date. In addition, the Company’s internal engineers evaluate all properties on a quarterly basis.