There are a number of different reactors in use, most commonly water-cooled pressurised or boiling water reactors - though other reactor types are kept cool with the help of liquid metal, gas or molten salt.
The study identified future potential electric generation capacity of 158 gigawatts for advanced coal, 78 gigawatts for water and dry-cooled concentrated solar energy and 515 gigawatts for large nuclear reactor plants.