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Energy and Related Sales, Net (Tables) | 12 Months Ended
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Dec. 31, 2017
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Summary of Energy and Related Sales Net | The following table summarizes this activity for each of the past three years:
| Year ended December 31 |  |
In thousands | 2017 |  |  |  | 2016 |  |  | 2015 |  |
Energy sales | $ | 3,258 |  |  |  | $ | 3,613 |  |  | $ | 5,315 |  |
Costs to produce |  | (3,986 | ) |  |  |  | (3,972 | ) |  |  | (4,428 | ) |
Net |  | (728 | ) |  |  |  | (359 | ) |  |  | 887 |  |
Renewable energy credits |  | 5,854 |  |  |  |  | 6,500 |  |  |  | 4,777 |  |
Total | $ | 5,126 |  |  |  | $ | 6,141 |  |  | $ | 5,664 |  |

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- Definition Schedule of revenues and expenses directly related to the sales of power generated by the Company not otherwise consumed in operations. + References No definition available. + Details
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