Cleaning Up Coal’s Act

Cleaning Up Coal’s Act
New projects offer the chance to tap inaccessible reserves, as well as limit the release of harmful gases

BEIJING — India and China are at the forefront of a new wave in clean-coal technology that has the potential to tap enormous and otherwise inaccessible coal reserves — and to slow the speed of climate change.

The Asian giants are investigating large-scale commercial projects that would produce energy by burning the coal where it lies, deep below the Earth’s surface. Building on pilot projects in the U.S. and elsewhere, the two countries are also looking at the possibility of capturing and permanently storing underground the gases produced, like carbon dioxide, which scientists believe cause global warming.

The underlying technology is one pioneered by the Soviets during the 1930s, called underground coal gasification — a way to tap energy from coal that was impossible or too costly to bring to the surface. A borehole is drilled down to the coal seam, which is then ignited. Oxygen is forced down through the borehole to feed the combustion. Gases produced by the combustion are then forced out a second borehole to the surface, where they are harnessed to turn turbines or for the production of chemicals. A power plant in Uzbekistan has been using the process for nearly 50 years. But elsewhere the practice was largely abandoned as increasing reserves of oil and natural gas were discovered, providing a cheaper alternative.

Wall Street Journal