The term "coal" encompasses a broad variety of solid fossilised forms of sediment, the composition of which can vary enormously. While brown coal (or lignite) can be traced back to a relatively recent geological era (approximately 50 million years ago), black (or bituminous) coal dates back to a much earlier period (around 300 million years ago). This means that the latter's carbon content (and thus its calorific value) is much higher due to the longer lasting process of carbonization.
Among the non-renewable forms of energy, coal has by far the greatest reserves throughout the world. One of the advantages of coal is that it is relatively evenly distributed all over the planet. According to figures from BP's Statistical Review of World Energy, the worldwide proven reserves of coal amount to around 890 billion tonnes. BP reported that global production reached 7'896 million tonnes (mt) in 2013. The biggest producers were China (3'680 mt), the USA (893 mt), India (605 mt), Australia (478 mt), Indonesia (421 mt) and Russia (347 mt). By way of comparison, the EU member states extracted a total of 543 mt of coal. Most of the coal produced was also consumed in the countries listed above, plus in Japan (5% of total consumption) and in South Korea (3%). In 2013, the EU accounted for around 7.5% of global coal demand (of which 3% for Germany alone). If we assume that global consumption remains at the 2013 level, then the proven reserves of coal will last for more than a century. However, in recent years coal has experienced a renaissance because primarily of the economic boom in Asia. According to BP's figures, coal consumption grew by 47% globally between 2003 and 2013. China accounted for 80% and India for around 12% of the increase. According to the International Energy Agency, coal consumption is likely to rise further over the long run. In terms of climate protection, however, coal represents a significant problem since its combustion results in high CO2 emissions. According to the IEA, new environmental protection regulations (not least in China and the USA) and increased competition from gas will bring the increase in coal consumption down to an average of 0.5% per annum between now and 2040.
In Switzerland, coal was the main energy source until the middle of the twentieth century and it was mostly used in the form of primary energy. Through a process of gasification, coal was also transformed in a secondary energy called coal gas or town gas. From 1950 onwards, coal has been rapidly displaced by oil, which is much easier to transport and store. By 1973, the proportion of coal to Switzerland's gross energy consumption was lower than 2% and as it appears in Table 10 of the Swiss Overall Energy Statistics 2014, it has remained close to 0.5% since 1996. This fuel has become so insignificant in Switzerland's energy mix that in 1998 the Federal Council repealed the requirement for coal importers to hold compulsory stocks in order to face supply disruptions. Today the cement industry accounts for more than 80% of coal use in our country. However, cement-makers increasingly give preference to alternative energy sources such as used tyres, sewage sludge, meat and bone meal, and other non-recyclable waste materials. This way they can improve their carbon footprint and gain exemption from the CO2 levy. The latter was introduced in 2008 and increased already twice (in 2010 and 2014). This levy is currently 60 Swiss francs per tonne of CO2, which is roughly equivalent to 150 Swiss francs per tonne of coal. In view of the high tax burden and the lively debate on conventional thermal power plants (especially coal-fired power plants abroad in which Swiss companies have a stake), there is little likelihood that coal will again become an important component of Switzerland's energy mix.