Steam coal for power generationSteam coal is a coal grade between bituminous coal and anthracite coal, and was once widely used as a fuel for steam locomotives. Smallsteam coalnuggets were also used as a fuel for domestic water heating and is now commonly used by utility companies to generate electricity.
Steam coal is primarily used as a solid fuel to produce electricity and heat through combustion. China is the world's largest coal producer and over two-thirds of China's electricity comes from steam coal. When steam coal is used for electricity generation, it is usually pulverized and then burned in a furnace below a boiler. The heat from the furnace boils the water to convert to steam which turns the turbines to generate electricity. The thermodynamic efficiency of boiling water to turn the turbines has improved over time. Older coal power plants are significantly less efficient than modern coal power plants and produce higher levels of waste heat, i.e. heat that does not directly effect the boiling of water. Modern steam turbines with advanced thermodynamic features have reached about 35% thermodynamic efficiency for the entire process.
To date, the most thermally efficient automotive internal combustion engine belongs to Mercedes-AMG's Formula 1 team, with an efficiency of 50 percent; AMG hopes the F1-derived engine in the Project One street-legal supercar will achieve 41-percent thermal efficiency, which would make it the most thermally efficient production-car engine in history...
The thermal efficiency of modern steam turbine plants with reheat cycles can reach 47%, and in combined cycle plants, in which a steam turbine is powered by exhaust heat from a gas turbine, it can approach 60%.
Operated by German utility EnBW, the plant achieves 47.5% net thermal efficiency while producing 912MW of electricity, making it one of the world's most efficient hard coal-fired steam power plants.
China build the double-reheat 1,000-MW ultrasupercritical Guodian Taizhou II Unit 3, the IEA says. The unit has been in operation since September 2015, and it reaches an efficiency of 47.82%, the highest globally for a double-reheat plant. The IEA also notes: “Every Chinese power plant is equipped with and SO2 control equipment, and almost all have NOx removal devices. All coal-fired plants will have to be ultra-low-emission by 2020.” The agency pegs China’s successes on the rapid implementation of tight environmental and performance standards, Interesting science essay!