Note 5 - Property, Plant and Equipment

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Property, Plant and Equipment Disclosure [Text Block]

5.

Property, Plant and Equipment

The following table sets forth the Company’s property, plant and equipment by classification (in thousands).

					December 31,
	(in years)				201 8			201 7
Construction in progress			–		$	3,478		$	479
Plant machinery and equipment			10			16,285			16,284
Site improvements			10			7,055			7,051
Agri-Energy Retrofit asset			20			70,842			70,842
Lab equipment, furniture and fixtures and vehicles			5			6,574			6,513
Demonstration plant			2			3,597			3,597
Buildings			10			2,543			2,543
Computer, office equipment and software			3			1,848			1,795
Leasehold improvements, pilot plant, land and support equipment		2	—	5		2,542			2,536
Total property, plant and equipment						114,764			111,640
Less accumulated depreciation and amortization						(47,728	)		(41,271	)
Property, plant and equipment, net					$	67,036		$	70,369

The Company had

no

 outstanding capital lease obligations as of

December 31, 2018

and

2017,

respectively. 

The Company recorded

$6.5

million,

$6.6

 million, and

$6.7

 million of depreciation expense for the years ended

December 31, 2018,

2017,

and

2016,

respectively, including

$6.3

 million,

$6.2

 million, and

$6.0

million of depreciation expense in cost of goods sold for the years ended

December 31, 2018,

2017

 and

2016

 respectively.