The Resources of the Earth - Thanatia: The Destiny of the Earth's Mineral Resources - page 148

Table 6.4 Rank of coal according to the norm ASTM D388
Class rank Fix carbon Volatiles HHV, MJ/kg

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Anthracite
Anthracite 98 2

Meta-anthracite 92 98 2 8

Semianthracite 86 92 8 14

Bituminous
Low-volatile 78 86 14 22

Medium volatile 69 78 22 31

High-volatile A - 69 31 - 32.56

High-volatile B 30.24 32.56

High-volatile C 26.75 30.24

Subbituminous
Subbituminous A 24.42 26.75

Subbituminous B 22.1 24.42

Subbituminous C 19.31 22.1

Lignite
Lignite A 14.65 19.31

Lignite B 14.65

around 1,965 Gt. But as the EWG (2007) 12 argues, estimated coal resources have
declined from 10 billion tonnes of coal equivalent (8,300 Mtoe) to about 4.5 billion
( 3,750 Mtoe), representing a decline of 55% within the last 25 years. Furthermore,
this downgrading of estimated coal resources is a trend supported by each new
assessment. Therefore it is possible that resource estimates will be further reduced
in the future. That said, there is another young form of coal, peat, (partially decayed
plant matter together with minerals), which has been used as a fuel for thousands
of years and is still in use, particularly in northern Europe. Peat reserves have not
been estimated but are considered to be very large.
Unlike oil or natural gas, coal has a more even global distribution, with rather
balanced consumption and production rates (see Fig. 6.6). At the end of 2010, world
coal consumption was 3,555.8 Mtoe (BP, 2011) with demand expected to more than
double by 2030. The International Energy Agency (IEA) has estimated that more
than 4,500 GW from new power plants (half of them in developing countries) will
be required in this same period (IEA, 2004).

6.6.6.2 Oil and natural gas

Oil and natural gas have proven to be economical, e cient and relatively clean fuels.
As a result, by 1950, they had overtaken coal as the primary source of energy.
Almost without exception, petroleum and natural gas are associated with sed-
imentary rocks of marine origin. Both are mixtures of hydrocarbon compounds
with minor amounts of sulphur, nitrogen and oxygen. Hydrocarbon production
takes place in two stages (Leet et al., 1982). First, biological, chemical and physical
12 EWG: Energy Watch Group.