Worse Than Gasoline

Liquid coal—produced when coal is converted into transportation fuel—would at best do little to rein in climate change and would at worst be twice as bad as gasoline in producing the greenhouse gases that blanket the earth and lead to warming.

The conversion technology is well established (the Germans used it during World War II), and liquid coal can power conventional diesel cars and trucks as well as jet engines and ships. Coal industry executives contend that it can compete against gasoline if oil prices are $50 a barrel or higher. But liquid coal comes with substantial environmental and economic negatives.
On the environmental side, the polluting properties of coal—starting with mining and lasting long after burning—and the large amounts of energy required to liquefy it mean that liquid coal produces more than twice the global warming emissions as regular gasoline and almost double those of ordinary diesel. As pundits have pointed out, driving a Prius on liquid coal makes it as dirty as a Hummer on regular gasoline.

One ton of coal produces only two barrels of fuel. In addition to the carbon dioxide emitted while using the fuel, the production process creates almost a ton of carbon dioxide for every barrel of liquid fuel. Which is to say, one ton of coal in, more than two tons of carbon dioxide out. Congressional and industry proponents of coal-to-liquid plants argue that the same technologies that may someday capture and store emissions from coal-fired plants will also be available to coal-to-liquid plants. But even if the carbon released during production were somehow captured and sequestered—a technology that remains unproven at any meaningful scale—some studies indicate that liquid coal would still release 4 to 8 percent more global warming pollution than regular gasoline.

Scientific American