China's efforts to reduce air pollution could be negated by its unregulated and unmonitored burning of petcoke, a fuel dirtier than coal, an expert on Chinese climate and energy policy said Tuesday in Washington D.C.
Petroleum coke is a cheap byproduct of oil refining that China has increasingly consumed in the last decade, as runaway demand for industrial fuel has driven up coal prices. Most of the 33 million metric tons of petcoke burned in China in 2013 came from Chinese refineries, said Wang Tao, a resident scholar with the Carnegie-Tsinghua Center for Global Policy in Beijing, but 7 million tons came from the U.S.
"When the U.S. imported more of the oil from the tar sands in Canada, the U.S. ended up with a huge pile of petcoke in your own backyard," Wang said Tuesday in an appearance at the Dirksen Senate Office Building. "And there’s no way to use them, so they actually export them to different countries including China."
In an industrial furnace, Petcoke behaves like coal, but in the atmosphere its emissions behave worse than coal’s. Petcoke emits 11 percent more greenhouse gases than coal, Wang writes in a paper he published May 31, with "a higher sulfur content… and various heavy-metal contaminants, including mercury, arsenic, chromium, nickel, and cadmium, as well as dioxins, hydrogen chloride, and hydrogen fluoride that are emitted when it is combusted."
"If burned in a regular furnace or pulverized-coal-fired power plant, the toxic metal and sulfur dioxide emissions of petcoke are higher than those of coal."
Sulfur dioxide offsets the warming effect of greenhouse gases, but the offset is relatively shortlived before sulfur dioxide drops out of the atmosphere and creates health problems in China's cities, while Petcoke’s higher greenhouse gas content lingers.
Chinese government officials have not caught on to the problem yet, Wang said. "Chinese policymakers are not yet fully aware of petcoke’s rapid proliferation, and data on petcoke consumption in China is lacking and far from transparent," Wang writes in the paper.
"This has not been recognized by the Chinese government as a major source," he added Tuesday at the D.C. forum sponsored by the Environmental and Energy Study Institute and the World Resources Institute.
China burns about 4 billion tons of coal annually, but petcoke contains 3 to 7 times more sulfur.
"When you compare the consumption of petcoke to the consumption of coal you realize that the contribution of petcoke could offset all the efforts China has made in terms of reducing the air pollution sources of sulfur dioxide."
The Chinese are not the only ones overlooking petcoke, Wang said: "These additional carbon emissions from petcoke have not historically been figured fully into calculations of the climate impacts of extra-heavy oils, such as those from Canadian oil sands and Venezuela, from which more petcoke is produced."
Wang sees the problem not only as a threat to China's progress, but as an opportunity for international cooperation.
"This requires our governments to work together to make certain that we find the best way to address the sulfur dioxide contribution from petcoke, not simply export it from one country to another country and burn it."