v3.20.2
Segment and geographic information - EBITDA (Detail)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2020
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2020
USD ($)
segment
Sep. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Segment and geographic information          
Number of reportable segments | segment     4    
Project revenues $ 65.2 $ 71.1 $ 200.3 $ 215.4  
Segment assets 840.4 997.2 840.4 997.2 $ 935.6
Project Adjusted EBITDA 49.5 48.9 137.1 153.2  
Change in fair value of derivative instruments (8.1) (1.0) (5.6) 8.3  
Depreciation and amortization 18.8 20.2 58.3 60.6  
Interest, net 0.8 0.8 2.1 2.0  
Insurance loss (6.2) 1.0 (6.2) 1.0  
Other project (income) expense       1.2  
Project income (loss) 38.0 27.9 82.3 80.1  
Administration 5.6 5.5 16.8 17.3  
Interest expense, net 10.8 10.9 31.7 33.0  
Foreign exchange (gain) loss 5.1 (2.8) (6.2) 7.1  
Other income (expenses), net (3.8) (0.2) (2.7) 0.7  
Net income (loss) before income taxes 20.3 14.5 42.7 22.0  
Income tax expense 2.5 0.2 5.2 2.4  
Net income (loss) 17.8 14.3 37.5 19.6  
Solid Fuel          
Segment and geographic information          
Project revenues 26.7 26.1 67.4 64.5  
Segment assets 229.7 295.6 229.7 295.6  
Project Adjusted EBITDA 17.1 13.2 23.3 31.5  
Depreciation and amortization 5.7 6.0 16.8 17.9  
Interest, net 0.6 0.8 2.0 2.3  
Insurance loss   1.0   1.0  
Project income (loss) 10.8 5.4 4.5 10.3  
Net income (loss) before income taxes 10.8 5.4 4.5 10.3  
Net income (loss) 10.8 5.4 4.5 10.3  
Natural Gas          
Segment and geographic information          
Project revenues 29.1 35.1 86.7 99.6  
Segment assets 208.4 251.3 208.4 251.3  
Project Adjusted EBITDA 27.1 29.6 79.1 80.6  
Change in fair value of derivative instruments (6.3) (2.6) (9.3) 0.1  
Depreciation and amortization 8.2 9.3 26.6 28.0  
Interest, net       (0.3)  
Other project (income) expense   (0.1)   1.2  
Project income (loss) 25.2 23.0 61.8 51.6  
Net income (loss) before income taxes 25.2 23.0 61.8 51.6  
Net income (loss) 25.2 23.0 61.8 51.6  
Hydroelectric          
Segment and geographic information          
Project revenues 9.2 9.7 45.5 50.6  
Segment assets 353.0 371.6 353.0 371.6  
Project Adjusted EBITDA 5.6 6.3 35.7 41.2  
Depreciation and amortization 4.9 4.9 14.7 14.6  
Project income (loss) 0.7 1.4 21.0 26.6  
Net income (loss) before income taxes 0.7 1.4 21.0 26.6  
Net income (loss) 0.7 1.4 21.0 26.6  
Corporate          
Segment and geographic information          
Project revenues 0.2 0.2 0.7 0.7  
Segment assets 49.3 78.7 49.3 78.7  
Project Adjusted EBITDA (0.3) (0.2) (1.0) (0.1)  
Change in fair value of derivative instruments (1.8) 1.6 3.7 8.2  
Depreciation and amortization     0.2 0.1  
Interest, net 0.2   0.1    
Other project (income) expense   0.1      
Project income (loss) 1.3 (1.9) (5.0) (8.4)  
Administration 5.6 5.5 16.8 17.3  
Interest expense, net 10.8 10.9 31.7 33.0  
Foreign exchange (gain) loss 5.1 (2.8) (6.2) 7.1  
Other income (expenses), net (3.8) (0.2) (2.7) 0.7  
Net income (loss) before income taxes (16.4) (15.3) (44.6) (66.5)  
Income tax expense 2.5 0.2 5.2 2.4  
Net income (loss) $ (18.9) $ (15.5) $ (49.8) $ (68.9)