Correct Answer - Option 1 :
15 to 20 years
The average life span of a hydro power plant is somewhere from 60 to 100 years.
Nuclear stations were originally designed for a life of about 40 years.
The average life span of a coal power plant is somewhere from 40 to 50 years.
For a diesel generating station the useful life is expected to the around
15 to 20 year.