Direct Carbon Fuel Cells (DCFC)

Direct Carbon Fuel Cells are much like the direct fuel cells that rely on polymer exchange membranes. The major difference is that they have a solid ceramic exchange membrane and thus run at much higher operating temperatures. There are DCFCs that utilize molten electrolytes as well.

Function and Reactions of DCFCs

At the anode, oxygen and carbon are combined to produce carbon dioxide and electrons. This is a very different reaction from most other fuel cells. The carbon to start the reaction can come from many sources including coal, wood, straw, and hydrocarbons that are not fossilized.

Coal is the primary focus of these fuel cells as they are intended for large scale power production utilizing resources that are immediately available. They are, to some extent, an effort to move industrialized nations away from reliance on petroleum.

Benefits and Drawbacks of DCFCs

These fuel cells are capable of large scale power production. Individual units can produce 100 kW and be grouped together into megawatt generating facilities. When run on coal, they are roughly twice as efficient as modern coal power plants, which extract roughly 45% of the energy contained within coal.

Direct carbon fuel cells are touted as “pollution fee,” which is only partially true. These fuel cells do not produce smoke and release contaminants into the atmosphere, making them substantially cleaner than modern coal-fired power plants. However, they do produce carbon dioxide.

DCFCs are often sold as “carbon-capture ready,” which means that the carbon dioxide they produce could be collected and disposed of in a way that prevents its ejection into the atmosphere. However, the keyword in these statements is also “ready.” The systems are capable of carbon capturing, but they do not come equipped to do so. Capturing carbon has two problems. First, it adds to the expense of these systems. Second, and more importantly, the technology for storing captured carbon is still in its infancy, with most experts providing 20 years as a reasonable estimate of when the technology will be available on a meaningful scale.