In a comment to the Ap Lei Chau power station, David wrote: It looks as though we can follow the progress from 1 to 5 generating units by the number of chimneys in the photos.
Yes, that's true:
Note: The dates given refer to the year when the photos were taken, not when the chimneys were built.
Zero (June 1967):
One (June 1968):
Two (1974):
Three (1976):
Four ([end of]1977):
Five (August 1980):
There were 5 chimneys by…
There were 5 chimneys at the full mature height by 1978 according to this archival footage of Hong Kong filmed in 1978 by an Austrian filmmaker - please refer to scene at 10:40
Also another archival footage from May 1978 showing the five chimneys at mature height.