Nature of the business, Assets acquired (Details) $ in Millions |
Feb. 28, 2018
USD ($)
MW
|
Jul. 30, 2015 |
|---|---|---|
| Kaxu [Member] | ||
| Nature of the business [Abstract] | ||
| Percentage interest acquired | 51.00% | |
| Mini- Hydro [Member] | ||
| Nature of the business [Abstract] | ||
| Percentage interest acquired | 100.00% | |
| Gross capacity | MW | 4 | |
| Acquisition purchase price | $ | $ 9 |