Lignite
Brown coal: the lowest-rank coal, with high moisture and low energy content, burned mostly in mine-mouth power plants and the most carbon-intensive major source of electricity.
Lignite is geologically young coal with 30–60% moisture and a lower heating value of roughly 5–15 MJ/kg, compared with 24–30 MJ/kg for hard (bituminous) coal. Its low energy density makes transport uneconomic, so it is burned in large plants next to open-pit mines.
High moisture lowers boiler efficiency: older units operate at 30–36%, while modern supercritical lignite plants such as Niederaussem K in Germany reach about 43% with pre-drying. Lignite also emits more sulphur and mercury per unit of electricity and causes large-scale land disturbance; Germany's Rhineland mines cover tens of square kilometres and have displaced villages.
Main producers are Germany, China, Russia, Türkiye, Australia (Victoria), Poland, the United States, Greece, Serbia and Czechia. With an EU carbon price of EUR 70–90/t, carbon alone adds EUR 70–100/MWh to lignite generation, which is why EU lignite output fell sharply after 2019. Germany's coal exit law sets 2038 as the final date, with Rhineland lignite brought forward to 2030; Greece plans to close its last lignite units by 2028.
Related terms
All terms →- Carbon intensity of electricity
The mass of CO2 (or CO2e) emitted per unit of electricity generated or consumed, usually expressed in grams per kilowatt-hour (gCO2/kWh).
- Carbon price
A cost applied per tonne of CO2e emitted, through a carbon tax or an emissions trading system, so that the climate damage of emissions enters market prices.
- Calorific value (HHV / LHV)
The heat released by complete combustion of a unit quantity of fuel; the higher (gross) value includes condensation heat of water vapour, the lower (net) value excludes it.
- Emissions Trading System (ETS)
A cap-and-trade market in which a regulator caps total emissions, issues tradable allowances, and requires covered installations to surrender one allowance per tonne emitted.
- Heat rate
The fuel energy a thermal power plant consumes per kWh of electricity generated; the inverse of efficiency, usually in BTU/kWh or kJ/kWh.