Compared with the efficiency of collectors or of turbines the efficiency of the
chimney is relative small. So the efficiency of the chimney is the determining
efficiency.
- flat collector depending to the air throughput: up to 70% and approximately 50%
over a year
- a chimney like the one mentioned (height about 1000m): just roughly 3%
- efficiencies of turbines and generators are surely higher than 70%
At least that is the reason for the height.