Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of useful lives of property plant and equipment

The estimated useful lives of the Company’s property, plant and equipment reflect the expected consumption of the economic benefit of these assets as noted in the following table:

Buildings and improvements	5 - 30 years
Machinery and equipment	1 - 43 years
Gas mineral rights	15 - 25 years

Summary of useful lives of intangible assets other than goodwill

The estimated useful lives of separately identified intangible assets are as follows:

Interconnection	10 - 25 years
Customer contracts	2 - 15 years
Emissions allowances	Indefinite
Land use rights	Indefinite