In its latest Medium-Term Coal Market Report the International Energy Agency (IEA) forecasts a slowing of coal demand growth but no retreat in its global use. That won’t surprise energy realists, but the item I wasn’t expecting was the reference in the IEA press release to growing efforts in China to convert coal into liquid fuels and especially synthetic natural gas (SNG). It’s not hard to imagine China’s planners viewing SNG as a promising avenue for addressing the severe local air pollution in that country’s major cities, but the resulting increase in CO2 emissions could be substantial. It could also affect the economics of natural gas projects around the Pacific Rim.
Air quality in China’s cities has fallen to levels not seen in developed countries for many decades. There’s even a smartphone app to help residents and visitors avoid the worst exposures. Much of this pollution, in the form of oxides of sulfur and nitrogen and particulate matter, is the result of coal combustion in power plants. Although China is adding wind and solar power capacity at a rapid clip, after years of exporting most of their solar panel output, the scale of the country’s coal use doesn’t lend itself to easy or quick substitution by these renewables.
Natural gas offers a lower-emitting alternative to coal on a larger scale than renewables. Existing coal-fired power plants could be converted to run on gas or replaced with modern combined-cycle gas turbine power plants. Gas-fired power plants emit up to 99% fewer local, or “criteria” pollutants than coal plants, especially those with minimal exhaust scrubbing.
Unfortunately, China doesn’t have enough domestic natural gas to go around. Despite potentially world-class shale gas resources and the rapid growth of coal-bed methane and more conventional gas sources, natural gas supplies only 4% of China’s energy needs. Imported LNG can help fill the gap, but it isn’t cheap. What China has in abundance is coal. Converting some of it to SNG could boost China’s gas supply relatively quickly–perhaps faster than the country’s shale gas infrastructure and expertise can gear up.