The design life of power plants is estimated to gauge economic viability of a plant, but the plants can run far longer, says Shukla.
Power houses in hydropower plants, for instance, may be designed for 30 years, but their dams have a longer life. The Bhakra project, for instance, completed 50 years in 2013.
It has already lived its full lifetime, but based on silt deposition, the reservoir (Gobind Sagar lake) has a life of more than 300 years, according to the Bhakra Beas Management Board. Power from Bhakra is priced at just Rs 0.96 a unit (kilowatt an hour).