System Could Halve Emissions from Coal Plants

This illustration depicts a possible configuration for the combined system proposed by MIT researchers. At the bottom, steam (pink arrows) passes through pulverized coal, releasing gaseous fuel (red arrows) made up of hydrogen and carbon monoxide. This fuel goes into a solid oxide fuel cell (disks near top), where it reacts with oxygen from the air (blue arrows) to produce electricity (loop at right).

Image courtesy of MIT News; Illustration: Jeffrey Hanna

Is it possible to reach twice the fuel-to-electricity efficiency of today’s conventional coal plants? MIT scientists think so, and the result would be a 50 percent reduction in carbon dioxide emissions for a given amount of power produced.

According to a paper in the Journal of Power Sources, the key is combining coal gasification and fuel cells into a single system. Coal gasification is a way to extract burnable gaseous fuel from pulverized coal instead of burning the coal. Fuel cells produce electricity from a gaseous fuel by passing it through a battery-like system, where the fuel reacts electrochemically with oxygen from the air. Combining them would permit the two components to exchange heat with minimal energy losses.

Researchers believe the fuel cell would generate enough heat to sustain the gasification part of the process, which would eliminate the need for a separate heating system.

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