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Braunkohle als Hausbrand.jpg
A lignite stockpile (above) and a lignite briquette

Lignite, often referred to as brown coal, [1] is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It is considered the lowest rank of coal due to its relatively low heat content. It has a carbon content around 20-35% percent. [1] It is mined all around the world, is used almost exclusively as a fuel for steam-electric power generation, and is the coal which is most harmful to health. [2]



Lignite mining, western North Dakota, US (c. 1945) Lignite mining in Western North Dakota.jpg
Lignite mining, western North Dakota, US (c. 1945)

Lignite is brownish-black in color and has a carbon content from as low as 20-25 percent up to 60–70 percent, a high inherent moisture content sometimes as high as 75 percent, [1] and an ash content ranging from 6–19 percent compared with 6–12 percent for bituminous coal. [3]

Strip mining lignite at Tagebau Garzweiler in Germany Garzweiler surface mine, October 2018, -01.jpg
Strip mining lignite at Tagebau Garzweiler in Germany

The energy content of lignite ranges from 10 to 20 MJ/kg (9–17 million BTU per short ton) on a moist, mineral-matter-free basis. The energy content of lignite consumed in the United States averages 15 MJ/kg (13 million BTU/ton), on the as-received basis (i.e., containing both inherent moisture and mineral matter). The energy content of lignite consumed in Victoria, Australia, averages 8.4 MJ/kg (7.3 million BTU/ton).

Lignite has a high content of volatile matter which makes it easier to convert into gas and liquid petroleum products than higher-ranking coals. Unfortunately, its high moisture content and susceptibility to spontaneous combustion can cause problems in transportation and storage. It is now known that efficient processes which remove latent moisture locked within the structure of brown coal will relegate the risk of spontaneous combustion to the same level as black coal, transform the calorific value of brown coal to a black coal equivalent fuel, and significantly reduce the emissions profile of 'densified' brown coal to a level similar to or better than most black coals. [4] However, removing the moisture increases the cost of the final lignite fuel.


Layer of lignite for mining in Lom CSA, Czech Republic Lom CSA Most Czech Republic 2016 7.jpg
Layer of lignite for mining in Lom ČSA, Czech Republic

Because of its low energy density and typically high moisture content, brown coal is inefficient to transport and is not traded extensively on the world market compared with higher coal grades. It is often burned in power stations near the mines, such as in Australia's Latrobe Valley and Luminant's Monticello plant in Texas. Primarily because of latent high moisture content and low energy density of brown coal, carbon dioxide emissions from traditional brown-coal-fired plants are generally much higher per megawatt generated than for comparable black-coal plants, with the world's highest-emitting plant being Hazelwood Power Station [5] until its closure in March 2017. [6] The operation of traditional brown-coal plants, particularly in combination with strip mining, is politically contentious due to environmental concerns. [7] [8]

In 2014, about 12 percent of Germany's energy and, specifically, 27 percent of Germany's electricity came from lignite power plants, [9] while in 2014 in Greece, lignite provided about 50 percent of its power needs.

An environmentally beneficial use of lignite can be found in its use in cultivation and distribution of biological control microbes that suppress plant disease causing microbes. The carbon enriches the organic matter in the soil while the biological control microbes provide an alternative to chemical pesticides. [10]

Reaction with quaternary amine forms a product called amine-treated lignite (ATL), which is used in drilling mud to reduce fluid loss during drilling.


Pendant in lignite (jet) from the Magdalenian culture Pendeloque en lignite Marsoulas MHNT.PRE.2012.0.6.95.jpg
Pendant in lignite (jet) from the Magdalenian culture

Lignite begins as an accumulation of partially decayed plant material, or peat. Burial by other sediments results in increasing temperature, depending on the local geothermal gradient and tectonic setting, and increasing pressure. This causes compaction of the material and loss of some of the water and volatile matter (primarily methane and carbon dioxide). This process, called coalification, concentrates the carbon content, and thus the heat content, of the material. Deeper burial and the passage of time result in further expulsion of moisture and volatile matter, eventually transforming the material into higher-rank coals such as bituminous and anthracite coal.[11]

Lignite deposits are typically younger than higher-ranked coals, with the majority of them having formed during the Tertiary period.


Germany has the biggest deposits, [11] followed by China, Russia and United States. [12]


The Latrobe Valley in Victoria, Australia, contains estimated reserves of some 65 billion tonnes of brown coal. [13] The deposit is equivalent to 25 percent of known world reserves. The coal seams are up to 100 metres thick, with multiple coal seams often giving virtually continuous brown coal thickness of up to 230 metres. Seams are covered by very little overburden (10 to 20 metres). [13]


Lignite can be separated into two types. The first is xyloid lignite or fossil wood and the second form is the compact lignite or perfect lignite.

Although xyloid lignite may sometimes have the tenacity and the appearance of ordinary wood, it can be seen that the combustible woody tissue has experienced a great modification. It is reducible to a fine powder by trituration, and if submitted to the action of a weak solution of potash, it yields a considerable quantity of humic acid. [14] Leonardite is an oxidized form of lignite, which also contains high levels of humic acid. [15]

Jet is a hardened, gem-like form of lignite used in various types of jewelry.


Lignite mined in millions of metric tonnes
Country or territory1970198019902000201020112012201320142015
Flag of East Germany.svg  East Germany 261258.1280 [lower-alpha 1] [lower-alpha 1] [lower-alpha 1] [lower-alpha 1] [lower-alpha 1] [lower-alpha 1] [lower-alpha 1]
Flag of Germany.svg  Germany 108 [lower-alpha 2] 129.9 [lower-alpha 2] 107.6 [lower-alpha 2] 167.7169176.5185.4183178.2178.1
Flag of the People's Republic of China.svg  China 24.345.547.7125.3136.3145147145140
Flag of Russia.svg  Russia 145 [lower-alpha 3] 141 [lower-alpha 3] 137.3 [lower-alpha 3] 87.876.176.477.9737073.2
Flag of Kazakhstan.svg  Kazakhstan [lower-alpha 4] [lower-alpha 4] [lower-alpha 4]
Flag of Uzbekistan.svg  Uzbekistan [lower-alpha 4] [lower-alpha 4] [lower-alpha 4]
Flag of the United States.svg  United States 542.879.977.671.073.671.670.172.164.7
Flag of Poland.svg  Poland 36.967.659.556.562.864.36663.963.1
Flag of Turkey.svg  Turkey 14.544.460.970.072.568.157.562.650.4
Flag of Australia (converted).svg  Australia 32.94667.368.866.769.159.958.063.0
Flag of Greece.svg  Greece 23.251.963.956.558.761.8544846
Flag of India.svg  India 514.124.237.742.343.54547.243.9
Flag of Indonesia.svg  Indonesia 40.051.360.
Flag of the Czech Republic.svg  Czechoslovakia 828771 [lower-alpha 5] [lower-alpha 5] [lower-alpha 5] [lower-alpha 5] [lower-alpha 5] [lower-alpha 5] [lower-alpha 5]
Flag of the Czech Republic.svg  Czech Republic [lower-alpha 6] [lower-alpha 6] [lower-alpha 6] 50.143.846.643.54038.338.3
Flag of Slovakia.svg  Slovakia [lower-alpha 6] [lower-alpha 6] [lower-alpha 6]
Flag of Yugoslavia (1946-1992).svg  Yugoslavia 33.764.1 [lower-alpha 7] [lower-alpha 7] [lower-alpha 7] [lower-alpha 7] [lower-alpha 7] [lower-alpha 7] [lower-alpha 7]
Flag of Serbia.svg  Serbia [lower-alpha 8] [lower-alpha 8] [lower-alpha 8] 35.5 [lower-alpha 9] 37.840.63840.129.737.3
Flag of Kosovo.svg  Kosovo [lower-alpha 8] [lower-alpha 8] [lower-alpha 8] [lower-alpha 10] 8.7 [lower-alpha 11] 9 [lower-alpha 11] 8.7 [lower-alpha 11] 8.2 [lower-alpha 11] 7.2 [lower-alpha 11] 8.2 [lower-alpha 11]
Flag of North Macedonia.svg  North Macedonia [lower-alpha 8] [lower-alpha 8] [lower-alpha 8]
Flag of Bosnia and Herzegovina.svg  Bosnia and Herzegovina [lower-alpha 8] [lower-alpha 8] [lower-alpha 8] 3.4117.
Flag of Slovenia.svg  Slovenia [lower-alpha 8] [lower-alpha 8] [lower-alpha 8] 3.744.14
Flag of Montenegro.svg  Montenegro [lower-alpha 8] [lower-alpha 8] [lower-alpha 8] [lower-alpha 10] 1.922
Flag of Romania.svg  Romania 26.533.72931.135.534.124.723.625.2
Flag of Bulgaria.svg  Bulgaria 3031.526.329.437.132.526.531.335.9
Flag of Albania.svg  Albania 1.42.13014920
Flag of Thailand.svg  Thailand 1.512.417.818.321.318.318.11815.2
Flag of Mongolia.svg  Mongolia
Flag of Canada (Pantone).svg  Canada 69.411.
Flag of Hungary.svg  Hungary 22.617.3149.
Flag of North Korea.svg  North Korea 1010.
Source: World Coal Association [16]  · U.S. Energy Information Administration [17]  · BGR Energiestudie 2016 [18]  ·1970 data from World Coal (1987) [19]

no data available

  1. 1 2 3 4 5 6 7 East Germany became a part of Germany as a result of German reunification in 1990.
  2. 1 2 3 Data prior to 2000 are for West Germany only.
  3. 1 2 3 Data prior to 2000 represent the Soviet Union.
  4. 1 2 3 4 5 6 Country was a part of the Soviet Union during this time.
  5. 1 2 3 4 5 6 7 Czechoslovakia dissolved in 1993.
  6. 1 2 3 4 5 6 Country was a part of Czechoslovakia during this time.
  7. 1 2 3 4 5 6 7 Yugoslavia broke up in a process that concluded in 1992.
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Country was a part of Yugoslavia during this time.
  9. 2000 data is for Federal Republic of Yugoslavia.
  10. 1 2 Country was a part of Federal Republic of Yugoslavia during this time.
  11. 1 2 3 4 5 6 Albanians unilaterally declared independence from Serbia, but the country it is not member of UN and its status is heavily disputed.

See also

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NLC India Limited

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