High-efficiency coal-fired power plant: optimised environmental performance
High-efficiency coal-fired power plants sharply reduce the environmental impact of electricity generation from coal. They are a key technology in the energy transition, especially in countries where coal remains the main energy source.
How does a high-efficiency coal-fired power plant work?
In a high-efficiency coal-fired power plant, water is subjected to high temperature and pressure, forcing it to move directly from the liquid to the gaseous phase. The efficiency gains achieved by this operation reduce the amount of coal needed and hence lower the CO2 emissions from coal combustion that are released into the atmosphere. The higher the temperature and pressure, the greater the efficiency gains and thus the lower the environmental impact.
A power plant is called “supercritical” when the temperature exceeds 565 °C and the pressure exceeds 250 bars. Above 585 °C and 300 bars, the power plant is said to be “ultra-supercritical”
High-efficiency coal-fired power plants use about 20% less fuel and therefore emit about 20% less carbon (CO2). They also emit seven times less nitrogen oxides (NOx) and more than 10 times less sulphur oxides (SOx).
Fuzhou, EDF’s first high-efficiency coal-fired power plant
In China, where 75% of electricity is generated by coal-fired power plants, EDF is investing in the “supercritical” technology required to meet Chinese energy needs while limiting environmental impact.
EDF and the China Datang Corporation (CDT) power generation company signed an agreement in April 2014 providing for EDF to acquire a 49% interest in Datang International Fuzhou Power Generation Company Ltd (FPC). This joint company began construction of a high-efficiency coal-fired power plant with two 1,000 MW units in the south-eastern province of Jiangxi.
Fuzhou, which is set to begin operating in the spring of 2016, will be the first high-efficiency coal-fired power plant to be operated by EDF. The technology will ensure 43% efficiency (compared with 35% for a conventional coal-fired power plant) and reduce environmental impacts:
800 g/kWh CO2 emissions versus 900 g/kWh for a conventional power plant
100 mg/Nm3 nitrogen oxide (NOx) and sulphur oxide (SOx) emissions, versus 720 mg/Nm3 and 1,300 mg/Nm3 respectively in a coal-fired power plant without flue gas treatment
Towards new technologies
This joint venture marks a new step in the cooperation between EDF and Datang that began in 2006. It also marks the Group’s investment in the development of emerging technologies designed to reduce the environmental impact of thermal power plants:
Biomass used to fuel power plants: first experiments have been carried out at the Cordemais plant
Thermodynamic solar concentrators: mirrors are used to “concentrate” solar energy, which is used to produce steam to power a turbine and electricity generator. Such steam production can also be included in a combined cycle gas turbine to improve efficiency and environmental footprint
Independent water and power project (IWPP) plants, which combine electricity generation with a saltwater desalination plant. EDF Group plans to participate in developing this industrial sector and to this end has signed agreements with the leading desalination technology companies