Government says no to coal-fired power plants but yes to syngas-from-coal-fired power plants.
A Bold Policy on Coal-Fired-Plants
Just two weeks ago, China announced a ban on the construction of new coal-fired power plants in three areas of the country with severe air pollution.
TheGreenGrok gave China high marks for adopting the policy: any policy that limits the use of coal, the dirtiest of the fossil fuels, is a step in the right direction. In the case of power plants the gains on the climate front are huge -- natural gas produces about half as much carbon dioxide (CO2) basis as coal on a BTU to BTU basis.
But there was a caveat. The policy is a step in the right direction only if it actually leads to less coal usage on a net basis. If coal that would have been burned in the three affected regions ends up being used elsewhere, it’s another example of greenwashing a la the tried-and-true bait and switch. And the caveat is a biggie for China, a country with huge coal reserves.
So, is China really contemplating eschewing coal for cleaner fuels to address environmental issues like climate change? An article just out in the journal Nature Climate Change by my colleagues Chi-Jen Yang and Rob Jackson at Duke suggests that the answer is no.
Coal-Syngas Plans Would More Than Cancel Benefits from a Ban on Coal-fired Plants
Yang and Jackson report that China has approved a plan to develop a huge set of facilities designed to convert coal into synthetic natural gas. The process essentially involves placing coal, water and oxygen under high pressure and temperature until the coal releases a raw gas that can be separated into different components. The raw gas is further treated to remove impurities and produce methane or synthetic natural gas (syngas).
The plan is to use the syngas to fuel power plants designed to burn natural gas. Now, at first glance that might seem to be fine -- after all, natural gas is a relatively “clean” fossil fuel -- but in this case we’re talking about natural gas derived from coal.
Yang and Jackson write that the “life-cycle [greenhouse gas] GHG emissions [from syngas] are roughly seven times that of conventional natural gas.” If the syngas is used to produce electricity, “its life-cycle GHG emissions are ~36-82% higher than pulverized-coal-fired power.”
And without pollution controls for mercury and acid gases at the gasification plants, this process isn't cleaner, meaning poor air quality will be part of the bargain. And if all that's not bad enough, the plants are water-intensive, using 50 to 100 times more water to produce a unit of methane as compared to shale gas.
The Land of Contradiction
Currently nine syngas plants in the arid northwestern parts of the country have been approved, with an additional 30+ in the planning stages. The authors estimate that if just the nine approved plants are built, they would emit 21 billion metric tons of CO2 as compared to three billion metric tons that a conventional natural gas plant would emit over a plant's roughly 40-year lifetime. Further, should all these plants be built, “emissions would be an astonishing ~110 billion tonnes of CO2 over 40 years.”
Could it be that China has failed to account for emissions from gasification in its climate action plan or has Beijing come under the spell of the clean coal hype? Or is it just a case of China talking green while walking further and further down coal-emission road?