The power sector being the largest emitter of CO2 has a key role to play if India wants to achieve its target of going net-zero by 2070. This will mean that we would need to move away from coal-based generation and adopt renewable power instead, mainly wind and solar. Of course, it can be supplemented with hydro power, biomass and nuclear. This energy transition can only happen if one is able to decommission coal-based plants without any adverse effect of not being able to meet the system demand. Countries like USA, UK and Germany have been able to move away from coal. They were able to do this primarily due to availability of gas and also through a system of giving market signals coupled with strict environmental norms for coal-based generation. This working paper examines as to what is the ideal parameter for decommissioning of coal-based generation. Is it the age of the plant, its station heat rate (SHR) or any other parameter? It also examines whether it would be possible for India to undertake this energy transition easily so as to become net-zero by 2070.