Coal at a storage area in Edwardsport, Indiana. US Department of Energy data reveal that coal exports topped 107 million tons worth almost $16 billion in 2011, the highest level since 1991, and more than double the export volume from 2006. Doug McSchooler / Bloomberg

US coal exports reached their highest level in two decades last year on strong demand from Asia and Europe.

US Department of Energy data analyzed by The Associated Press reveal that coal exports topped 107 million metric tons worth almost $16 billion in 2011. That's the highest level since 1991, and more than double the export volume from 2006.

Much of the increase went to slake the thirst of power-hungry markets in Asia, where rapid development has sparked what the mining company Peabody Energy Corp calls a "global coal super cycle" that heralds renewed interest in the fuel.

The AP's analysis showed coal exports to South Korea leapt 81 percent last year to more than 10 million tons. India saw a 65 percent jump to 4.5 million tons. And Japan bought almost 7 million tons of US coal last year - a 119 percent increase - as the country sought alternatives to nuclear power after an earthquake and tsunami prompted the Fukushima nuclear complex meltdown.

Coal faces a tougher outlook in the United States, where competition from cheap natural gas and costly new rules for power plants are eroding its historic dominance in electricity generation.

Coal's share of the US power supply has fallen by more than 20 percent in the past several years, forcing companies to search out new customers or risk having to cut production from US mines that produced almost 1.1 billion tons last year.

US government projections released on Tuesday said demand for coal in the power sector could dip another 10 percent in 2012. That would drive total US coal use below a billion tons annually for only the second time since 1995.

Utilities burn almost all the coal consumed in the US to produce electricity.

"There's no question that our supplies of coal are adequate. The question is, how do we find new markets for coal to keep the share of electricity generation strong?" said Luke Popovich with the National Mining Association. "While its use is relatively declining here, it is absolutely soaring in most other places."

Exports also were up to Brazil, China and several European nations seeking high-quality coal for steelmaking, according to the US Energy Department data.

The department forecast exports will drop slightly over the next two years, then slowly climb to about 130 million tons annually by 2030. Countries worldwide consume more than 6 billion tons of coal annually.

Companies including Arch Coal Inc have offered far more optimistic scenarios under which exports continue to grow rapidly. St Louis-based Arch has predicted export capacity could reach 245 million tons by 2015.

To make that happen, companies want new or expanded coal ports on the West and Gulf coasts.

Pending proposals in the state of Washington would add tens of millions of tons of port capacity for coal that would be mined from the Powder River Basin of Montana and Wyoming.

Port expansions also are envisioned along the East Coast and in Texas, where Kinder Morgan Energy Partners plans to invest $140 million to expand a coal terminal in Houston.

"The US has lots of coal. It has a wonderful rail infrastructure. But the piece of the logistical puzzle that is weakest is terminals. To get to the next level of growth, the new terminals need to be built," said Jim Orchard, vice-president of Wyoming-based Cloud Peak Energy.

Cloud Peak exported 4.7 million tons to Asia last year from its Spring Creek mine near the Montana-Wyoming border - an increase of 42 percent from 2010. Orchard added that the only way export demand would dry up would be if economic growth in China and India came to an abrupt halt.

"High demand by China has rippled through the markets. It's really an issue of how long this demand is going to last," said Bill Watson, an analyst with the Energy Information Administration.

"The prices have been very high, so anybody who can mine and ship coal certainly has a lot of incentive to do that."