The silos, which are scheduled to start operation in July, are designed to blend cleaner-burning imported coal with China’s own high-polluting domestic coal, which is contaminated with sulfur and dust.

Coal blending will produce a mixture that will help electric utilities meet China’s steadily tightening environmental regulations. It will also increase the efficiency of coal-fired plants by slightly reducing the quantity of coal needed. Burning less coal means less greenhouse gases emitted.

But critics argue there is a darker side to cleaner coal.

“Anything that makes coal more cost effective, like blending, which is only enabling China to burn more coal, is bad news for the global struggle against carbon emissions,” said Orville Schell, the Arthur Ross director of the Center on U.S.-China Relations at the Asia Society in New York.

The Chinese government’s decision this month to import more coal in order to lessen power outages — and control rising coal prices — ensures that blending will increase rapidly.

Industry executives are quick to tout the practice’s environmental benefits. Blending “is a sound solution to reducing greenhouse gas and pollutants emissions from coal-fired power plants,” said Howard Au, the director and chairman of Petrocom Energy Ltd., which owns the blending facility here.

But environmentalists worry that by reducing the amount of sulfur and dust emitted from burning coal, blending makes coal more acceptable in the short-term and stalls the conversion to cleaner or renewable fuels. They say coal blending strengthens the case for companies — and countries — that want to continue to rely on coal for decades.

“Does it help with acid rain? Yes,” said Allen Hershkowitz, a specialist in Appalachian coal fields at the Natural Resources Defense Council, an environmental group based in New York. “It hurts us when it comes to global warming.”

Coal remains a particularly dirty form of electricity generation when it comes to producing climate-changing gases.

The global warming calculus for coal blending is less clear. Blending makes it easier to feed a power plant with exactly the right coal mixture at which its boilers work most efficiently. This means the plant can burn less coal and emit less greenhouse gas. How much less — and how does that improvement compare with switching to other fuels — varies a lot depending on the power plant and the coal it burns without blending. Better operating efficiency at the power plant helps offset the cost of blending, which can add up to 4 percent to the price tag of the coal.

China does not just have an ancient civilization, it also has a lot of very old coal. Much of it has been tightly compressed over millions of years. That has pluses and minuses.

Chinese coal releases a lot of heat when burned and has very little moisture left, two very desirable features, according to coal traders. But Chinese coal deposits also contain a lot of sulfur as well as so-called fly ash — dust that is not combustible and contributes to particulate air pollution.

China also has some deposits of young coal which has fairly low heat content and requires blending before it can be burned.

China has the third-largest coal reserves, after the United States and Russia, and consumes more coal than any other country. It accounted for nearly half the 7.3 billion metric tons burned around the world last year.

Four-fifths of China’s reserves, however, do not comply with the country’s standards for industrial use, according to the government-run China Coal Research Institute. Complicating matters, the China’s environmental regulators have signaled plans to reduce further the allowable levels of sulfur.

China led the world last year in clean energy investments, with $54.4 billion, according to a study by the Pew Charitable Trusts. But coal is still China’s dominant energy source, accounting for 73 percent of electricity capacity.

Because coal-fired plants run day and night — while alternatives like wind turbines and hydroelectric dams only run when enough wind or water is available — coal accounted for 83 percent of electricity generation last year.

Article source: http://www.nytimes.com/2011/06/15/business/energy-environment/15iht-sreCHINA15.html?partner=rss&emc=rss