China has already surpassed the U.S. as the world's largest carbon emitter. If China builds the proposed "40 massive projects to convert coal to synthetic natural gas (SNG), a process that would dramatically increase China’s greenhouse emissions, and emit huge volumes of toxins while consuming vast quantities of water", those emissions will skyrocket, writes Todd Woody about a new Duke University study published (PDF) Sept. 25 in Nature Climate Change.
The ironic part is that it is being done in the name of curtailing air pollution. More on that later.
The technology to convert coal to synthetic natural gas (SNG) is not new. The Duke University scientists, Robert Jackson and Chi-Jen Yang "suggest Chinese officials study the US’s failed experiment with SNG."
In the 1980s, the US Department of Energy provided a $2 billion loan guarantee to build the Great Plains Synfuels Plant. The plant went online in 1983 and within two years its operator filed for bankruptcy. The US Department of Energy bought the project for $1 billion and subsequently sold it for $85 million.
According to Jackson and Yang, "SNG emits seven times the greenhouse gases of natural gas. If it is burned to generate electricity, the carbon spew is up to 82% greater than a coal-fired power plant. Tailpipe emissions from a SNG-powered vehicle are twice those of a conventional car."
Nine of the 40 plants have been approved to date. They will be built in desert regions away from population centers but endanger limited water supplies.
"The idea is that natural gas will burn more cleanly in urban power plants and help detoxify the air in major cities like Beijing", writes Brad Plumer in The Washington Post's Wonkblog.
Now, the synthetic gas plants themselves would largely be located in inner Mongolia or Xinjiang, far out west and away from the major population centers. So the power plants near China's cities really could curtail local air pollution like sulfur dioxide and soot — natural gas does burn far more cleanly than coal in this regard. But it would come at the cost of vastly more emissions out west and accelerated global warming.
In addition to reducing urban air pollution, China "is seeking to lessen its dependence on overseas suppliers of (costly) liquefied natural gas (LNG)", writes Woody. However, "coal still remains king, Jackson told Quartz. 'China has abundant coal resources, and local and provincial interests push the system to use the coal,' he said in an email."
“Using coal to make natural gas may be good for China’s energy security,” Jackson, a professor of environmental sciences, said in a statement, “but it’s an environmental disaster in the making.”
So - how can China reduce air pollution, increase energy security, and not explode its greenhouse gas emissions? Warning: if you are a fracking opponent, you may not wish to read further. Plumer writes:
As Yang and Jackson show, fracking for shale gas [of which "China has massive reserves"] would be much less drastic from a climate-change perspective than building those big new SNG plants: Fewer carbon emissions, fewer toxins, less water needed. [See the bar charts showing lifecycle greenhouse gas emissions and water consumption for SNG, coal, and shale gas.]
"In my view, developing shale gas in China would be much smarter than making natural gas from coal, but unconventional energy extraction in China is still developing”, states Jackson near the end of the Quartz article.