Finite Lived Intangible Asset and Liability (Notes)
 9 Months Ended
Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]  
Finite Lived Intangible Assets And Liability [Text Block]
5.    Finite-Lived Intangible Assets and Liability
Finite-Lived Intangible Assets and Liability
The following presents the major components of the finite-lived intangible assets and liability (in thousands):
 
 
September 30, 2017
 
 
Weighted Average Remaining Life
 
Gross
 
Accumulated Amortization
 
Net
Intangible assets
 
 
 
 
 
 
 
 
Power purchase agreement
 
16
 
$
127,330

 
$
(15,668
)
 
$
111,662

Industrial revenue bond tax savings
 
25
 
12,778

 
(223
)
 
12,555

Other intangible assets
 
34
 
15,234

 
(935
)
 
14,299

Total intangible assets
 
 
 
$
155,342

 
$
(16,826
)
 
$
138,516

Intangible liability
 
 
 
 
 
 
 
 
Power purchase agreement
 
15
 
$
60,300

 
$
(8,238
)
 
$
52,062


 
 
December 31, 2016
 
 
Weighted Average Remaining Life
 
Gross
 
Accumulated Amortization
 
Net
Intangible assets
 
 
 
 
 
 
 
 
Power purchase agreement
 
13
 
$
97,400

 
$
(10,632
)
 
$
86,768

Other intangible assets
 
15
 
5,666

 
(539
)
 
5,127

Total intangible assets
 
 
 
$
103,066

 
$
(11,171
)
 
$
91,895

Intangible liability
 
 
 
 
 
 
 
 
Power purchase agreement
 
16
 
$
60,300

 
$
(5,637
)
 
$
54,663


The Company presents amortization of the PPA assets and PPA liability as an offset to electricity sales in the consolidated statements of operations, which resulted in net expense of $0.9 million and $2.4 million in electricity sales for the three and nine months ended September 30, 2017 and net expense of $0.7 million and $2.3 million for the same periods in 2016. For other intangible assets, the Company includes the amortization in depreciation and accretion in the consolidated statements of operations and recorded amortization expense of $0.1 million and $0.4 million for the three and nine months ended September 30, 2017 and amortization expense of $0.1 million and $0.2 million for the same periods in 2016.
The acquisition of the Broadview Project provided for future property tax savings as a result of the issuance of industrial revenue bonds during construction of the Broadview Project. The Company considered the future tax savings an intangible asset and calculated the fair value of the asset at the acquisition date. The tax savings was calculated by forecasting the difference between the property tax payments that the Broadview Project would be liable for if the industrial revenue bond structure was not in place and the actual payments in lieu of tax. The fair value of the property tax savings was recorded to finite-lived intangible assets, net on the consolidated balance sheets at the acquisition date, and such value will be amortized to depreciation and accretion in the consolidated statements of operations over the 25 year exemption period that remains as of the acquisition date. The Company recorded amortization expense of $0.1 million and $0.2 million for the three and nine months ended September 30, 2017, respectively, related to the industrial revenue bond tax savings intangible asset.
The following table presents estimated future amortization for the next five years related to the Company's finite lived intangible assets and liabilities (in thousands):
Year ended December 31,
 
Power purchase agreements, net
 
Industrial revenue bond tax savings
 
Other intangible assets
2017 (remainder)
 
$
1,079

 
$
128

 
$
152

2018
 
4,253

 
513

 
605

2019
 
4,253

 
513

 
605

2020
 
4,274

 
513

 
605

2021
 
4,253

 
513

 
605

Thereafter
 
41,488

 
10,375

 
11,727