Demand for coal has become so intense that at one point it was tipped to overtake oil as the biggest global fuel by 2030, by no less than the International Energy Agency (IEA).
This demand was driven overwhelmingly by China, which is responsible for almost half the world's coal usage.
Yet increasingly loud signals from Beijing suggest that its coal consumption may be close to its peak, causing price falls and analyst downgrades. Demand for the fuel in China could peak as early as 2015, according to senior research staff at China's National Development and Reform Commission, quoted in a recent Citi research note.
(Read more: Could coal's days be numbered?)
The country's new President, Xi Jinping, has declared his intention to reduce its dependence on fossil fuels, although this has so far mainly amounted to public statements rather than concrete action. The administration wants to clear some of the pollution for which Beijing and Shanghai have become notorious, and to reduce China's dependence on imported fuels.
There is an increased focus on renewable and nuclear energy, which is helping to halt the price of thermal coal's climb.
The country's economic growth is also slowing faster than many in the energy markets hoped, reducing the demand for industry-fuelling assets like coal.
(Watch:CanChina really change course on energy?)
China has become so dominant in the market that any movement in demand will affect global prices.
"Although lower prices may spur demand growth elsewhere, the demand slowdown in China should more than offset such gains," analysts at Citi wrote.
Coal exporting countries, the mining and equipment sectors have most to lose from the downturn, according to Citi.
Forecasts for coal's future price movements are still diverging widely. There could even be a boost from a restocking event, as China's stocks are now at their lowest levels since 2011, Deutsche Bank analysts have pointed out.
(Read more: New Process May Put Cleaner Face on Dirty Coal)
