Property, Plant and Equipment (Tables)

9 Months Ended

Sep. 30, 2021

Property, plant and equipment at September 30, 2021 and December 31, 2020 consisted of the following:


	Estimated Useful Life (in Years)	September 30, 2021		December 31, 2020
Energy systems	1 - 15 years	$	3,556,488	$	3,526,514
Machinery and equipment	5 - 7 years	1,484,790		1,448,024
Furniture and fixtures	5 years	193,698		193,698
Computer software	3 - 5 years	192,865		192,865
Leasehold improvements	*	450,791		450,792
		5,878,632		5,811,893
Less - accumulated depreciation and amortization		(3,961,149)		(3,528,047)
		$	1,917,483	$	2,283,846

* Lesser of estimated useful life of asset or lease term