We’ve already put together a separate guide where we outline what coal is, explain how it forms, & explain the different types of coal.
In the guide below however, we specifically discuss black and brown coal.
Summary – Brown vs Black Coal Comparison
Overall, there’s one type of brown coal, and three main types of black coal
Each of these types of coal has a different rank, and has different traits and qualities
We list these ranks and traits/qualities in the guide below
In general, black coal might be higher ranked, higher quality, harder, have a higher energy content and carbon content, and have a lower moisture content compared to brown coal
Black coal may also emit less carbon dioxide than brown coal
At the bottom of this guide, we list some potential pros and cons of brown coal specifically, and coal in general
What Is Brown Coal, & What Is Black Coal?
– Brown Coal
Brown coal is lignite
– Black Coal
Black coal includes sub-bituminous, bituminous and anthracite
How Brown Coal & Black Coal Form
We explained the formation process of coal, and brown coal and black coal in this guide.
Chronologically, the formation of brown coal happens before black coal, and in this order (from first to last):
– Lignite (brown coal) (peat progresses into Lignite)
– Sub-bituminous (black coal)
– Bituminous (black coal)
– Anthracite (black coal)
Brown Coal vs Black Coal: Key Differences
Some of the key differences between brown coal and black coal might be:
– How long they each take to form
Black coal may take longer to form in the coal formation process than brown coal
Black coal is many millions of years older than brown coal … (dynamicscience.com.au)
– The rank and quality of coal
Brown coal might be lower ranked and lower quality than black coal (which is higher ranked and higher quality)
Overall, the higher the rank of coal, the harder it might be, the higher it’s energy and carbon content, and the lower it’s water/moisture content
Less of the higher ranked forms of coal (in quantity) might be required to produce the same amount of energy as for lower ranked coal
ga.gov.au notes that: ‘As the coal increases in rank [from softer brown coal to harder black coal], the carbon content – and hence the energy content – increases, whilst the moisture content decreases’
– How hard or soft each one is (known as ‘hardness’)
Brown coal tends to be softer, and black coal harder
– Heating value
The higher the rank of coal, the higher the heating value (in Btu) might be
Black coal has a heat content of approximately 35300 kJ/kg where as brown coal has a heat content of approximately 28470 kJ/kg, depending on the water content (dynamicscience.com.au)
– Energy content
This is energy per unit, or, energy per kg
Higher ranked coal (black coal) might have a higher energy content
– Moisture content/water content
Which affects how dry the coal has to be before being combusted/burnt
Lower ranked coal (brown coal) might have a higher moisture content than higher ranked coal
Black coal … has a lower water content [… than brown coal, and …] Unlike black coal, brown coal must be dried before it is burnt (dynamicscience.com.au)
– Carbon content and carbon concentration
Higher ranks of coal (black coal) might have a higher % of fixed carbon, and the lower ranks of coal (brown coal) might have the least concentration of carbon
– Overall volatile matter
Volatile matter includes water, carbon dioxide and sulphur dioxide
As coal rank increases, volatile matter % in the coal decreases
– Where they are found geographically in the world
Brown and black coal might each be more abundant or more scarce in different geographic regions of the world
– How much of each type of coal there is in the world
There might be more black coal in the world in total than brown coal
ourworldindata.org notes that 70% of the coal in the world is high quality coal (black coal)
– Summary of the different traits of black coal and brown coal
Below is a paraphrased summary from usgs.gov of each type of black coal, and also brown coal:
[Anthracite is hard and black, contain a high % of fixed carbon, and a low % of volatile matter]
[Bituminous has a] high heating (Btu) value [and is] the most common type of coal used in electricity generation in the US]
[Sub-bituminous is black, and] has a higher heating value than lignite
[Lignite is brown coal, and is] the lowest grade coal with the least concentration of carbon
Brown vs Black Coal: Differences In Greenhouse Gas Emissions
ourworldindata.org has a graph/chart showing how much carbon dioxide each type of coal emits per unit of electricity produced
Generally, the lower quality the coal, the more greenhouse gases it might emit.
Some reports indicate that the emissions difference between high ranked coal and low ranked coal might be around the 9% to 10% mark.
In order of most to least emissions (from ourworldindata.org):
Lignite (brown coal)
Anthracite
Sub Bituminous Coal
Bitumen
unearthed.greenpeace.org also notes that soft coal like brown coal tends to emit more than hard coal like black coal
Potential Difference In Impact On Human Health & Mortality
Potential Pros and Cons Of Brown Coal
Paraphrased from unearthed.greenpeace.org, environmentvictoria.org.au, joannenova.com.au, wikipedia.org, and environmentvictoria.org.au, some of the potential pros and cons of brown coal might be:
Pros
– Might be a cheaper form of electricity than some other energy sources
For example, it may be cheaper than renewables when subsidies are taken into account
This might especially be the case where brown coal is abundant locally, and cheap to mine and use for electricity
– Might have a number of economic benefits
Such as providing jobs, income and supporting a local economy
environmentvictoria.org.au mentions Victoria in Australia may be an example of a place that receives these benefits
– Might help some countries reduce their foreign energy dependence
For example, it might help Poland and Germany reduce their dependence on foreign Russian natural gas
Cons
– Burning brown coal for energy may be more carbon intensive than black coal, and also natural gas
– May emit air toxins/air pollutants, poisonous heavy metals, and toxic chemicals
Such as NOx (nitrogen oxides), SO2 (sulphur dioxide), mercury, particulate matter
In some geographic regions, the concentration of these pollutants and chemicals in the air might not be adequately monitored or regulated too – which could compound the issue in some ways
-May have indirect social costs and health costs to consider
For example, environmentvictoria.org.au mentions that ‘The costs on the health system in Australia alone from air pollution might be up to $800 million’
It’s unclear how much coal pollution may contribute to this though
– Might be an inefficient way of generating energy inefficient
Because brown coal is wet when it is extracted and burned, it takes more brown coal (in quantity), to produce the same amount of power compared to black coal
– Brown coal might not be economically feasible to transport longer distances
environmentvictoria.org.au mentions this might be the case with Victorian brown coal (in Australia)
Because it contains up to 70 percent water (has a high moisture content), it isn’t suitable from an economic perspective for long distance transport, and isn’t used for export markets i.e. it may be restricted to some local markets
– The mining of brown coal may have a range of negative environmental and social effects
It may contribute to the pollution of groundwater and surface water sources, increase in the risk of flooding, and generally impact local mining communities in some regions
Potential Pros & Cons Of Coal In General
You can also read more about the pros and cons of coal in general in this guide
Sources
1. http://www.ga.gov.au/scientific-topics/minerals/mineral-resources-and-advice/australian-resource-reviews/black-coal
2. https://ourworldindata.org/fossil-fuels
3. https://unearthed.greenpeace.org/2014/08/28/five-reasons-expanding-brown-coal-mines-might-problem/
4. https://environmentvictoria.org.au/our-campaigns/safe-climate/problem-brown-coal/
5. http://joannenova.com.au/2019/04/solar-power-at-70-is-still-twice-the-price-of-brown-coal/
6. https://en.wikipedia.org/wiki/Clean_coal_technology#Clean_coal_and_the_environment
7. https://www.bettermeetsreality.com/types-of-coal-their-uses/
8. http://www.dynamicscience.com.au/tester/solutions1/electric/powerstation/brown%20coal.html
9. https://www.usgs.gov/faqs/what-are-types-coal?qt-news_science_products=0#qt-news_science_products
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