Many countries and companies are pursuing with vigour the concept of "clean coal," where toxic emissions of are reduced by over 90 percent and sulphur and greenhouse gas emissions are rendered virtually non-existent. Research is underway in Europe, North America and Asia on how to make use of the world's most abundant fossil fuel in ways that are environmentally and socially more acceptable.

While no one doubts coal will be with us for many generations to come, many are grasping at the quick fixes that would appear to make coal a "clean fossil fuel." But to date, the solutions remain elusive. In addition to unproven technologies -- at least on a scale that would make a real difference -- there is the thorny issue of costs, most of which would have to be borne up front.

The 2007 World Energy Outlook estimated that coal use, despite potential greenhouse gas emissions, will rise 70 percent by 2030 and will surpass petroleum as the dominant energy source. This poses a significant problem in reducing greenhouse gas emissions to levels that will avert the worst impacts of climate change.

Already there are thousands of coal fired power plants around the world which account for 40 percent of global greenhouse gas emissions and are the world's largest source of mercury, sulphur and nitrogen oxides.

There are over 600 coal-fired plants in the U.S., which has plans to develop at least 60 new coal plants in the next 10 years. European countries will put into operation about 50 coal-fired plants over the next five years.

Australia, the third highest emitter of greenhouse gases on the planet, receives 80 percent of its energy from coal. "Coal is set to play a big role in future Australian prosperity," said the architect of Australia's climate change review, Professor Ross Garnaut.

China has medium-term plans to build more than 500 coal-fired electricity plants and is opening one coal-fired plant each week. China receives 80 percent of its power needs from coal and India receives 65 percent.

In total over 1000 proposed coal-fired plants will be built in the next decade -- almost at the rate of one new plant every month for the next 10 years.

What are Clean Coal Technologies?

When burned, coal releases mercury, sulphur dioxide (which contributes to the formation of acid rain), nitrogen oxides (which forms smog) and carbon dioxide.

In developed countries, removing impurities from coal, such as mercury, through chemical washing is already common practice. Remaining contaminants including sulphur dioxide and nitrogen oxides are removed from flue gases via scrubbers and steam treatment.

Using a process called integrated gasification combined cycle (IGCC), which turns even the dirtiest coal into gas, 99 percent of the sulphur dioxide and nitrogen oxide emissions can be removed. The technology also removes up to 90 percent of mercury emissions.