Cutaway diagram of a simplified coal-fired thermal power station, where the chemical energy stored in coal is converted successively into thermal energy, mechanical energy, and finally electrical energy for continuous use and distribution across a wide geographic area. Each power plant is a highly complex, custom-designed system. Present construction costs, as of 2004, run to $1,300 per kilowatt, or US$650 million for a 500 MWe unit. Image credit: BillC |