"If it doesn't succeed, then the whole world will be energy poor," he said. "I believe that CCST will be made to work because we don't have many choices when it comes to energy sources." Building a coal-fired power plant with carbon capture and storage is probably 20 percent more expensive than a conventional coal boiler, plus some power output must be used to compress and move captured carbon dioxide, he said.

But even taking this into account, the WCI believes coal will remain competitive.

Coal is the only fossil fuel likely to be available in the next century, said Gerard McCloskey, chairman of industry publisher TMG.

"If future oil and gas availability is as limited as currently believed, coal must be fully optimised to meet energy needs," he said.

TMG predicts that all the major oil companies will reinvest in coal production very soon.

"If energy companies like Royal Dutch Shell want a future beyond 2030, getting a stack of coal reserves under their belts would be a nice precaution," McCloskey said.

TMG director and editor of Steam Coal Forecaster, David Price, added: "I'd expect to see a major revival of interest in coal among the oil companies within the next year. My hunch is that coal is already in the oil majors' budgets."

BIGGER SLICE

"We hope coal will have a bigger slice of the energy pie - it certainly looks as though it will," said Preston Chiaro, chairman of industry body WCI chairman and chief executive energy of Rio Tinto.

Coal provides 25 percent of global primary energy needs and fuel to generate 40 percent of the world's electricity, according to the WCI.

"We believe that coal will remain comparatively competitive within the energy mix, versus nuclear, oil and gas and renewables, even though we expect energy costs generally to keep rising," Chiaro said.

UK-based WCI, whose members are coal producers and traders, is a non-profit organisation which promotes coal as a strategic resource and whose aims include providing a voice for coal in policy discussions on energy and the environment.

Colin Gubbins, a director of The McCloskey Group that produces the group's long-term forecasts, was more confident that coal demand will increase.

"Even if we take the cautious view and assume coal fuels an unchanged percentage of power generation over the next few decades, because power demand will keep rising, the tonnage of coal consumed has got to rise also," he said.

"However, I also think that coal will provide a larger percentage of fuel for generation."

What ultimately happens to the global primary energy mix will also depend on market politics, said Price.

"It's possible that gas will once again only be supplied to industrial and domestic consumers rather than for generation, which will force the power sector to be more reliant on coal," he said.

Coal will continue to enjoy many advantages over oil and gas in decades to come, Chiaro said. Coal is easy to produce, requires no complex or costly technology is widely found and is relatively cheap to transport.

Coal is found in almost every country, with recoverable reserves in around 70, according to the WCI. At current output levels, proven reserves are estimated at 155 years, compared to proven oil and gas reserves of 41 and 65 years, the WCI says.

China, Russia, Indonesia and Australia arguably have the greatest potential for higher production and exports, according to WCI and TMG.

"There are places which haven't been thoroughly explored for coal, such as Western China, which is thought to have three times the reserves currently estimated for China as a whole," Price said.