Thermal power plants generate electricity through the combustion of coal. They work by heating water in a boiler to produce steam, which spins turbines that generate electricity. The majority of India's electricity comes from coal-based thermal power plants. Key components include the boiler, turbine, heat exchangers and condenser. Thermal plants produce ash and flue gases as byproducts, and have ash ponds and scrubbers to handle waste. Fly ash is also often recycled for uses like cement production and brick making.