VATIS UPDATE Article

Researchers at Massachusetts Institute of Technology (MIT), the United States, have come up with a plan that could contribute to that effort by making it possible to generate electricity from coal with much greater efficiency – possibly reaching as much as twice the fuel-to-electricity efficiency of today’s conventional coal plants. This would mean, all things being equal, a 50 percent reduction in carbon dioxide emissions for a given amount of power produced. The key is combining into a single system two well-known technologies: coal gasification and fuel cells.

In the combined system, these gases would then be piped from the gasifier to a separate fuel cell stack, or ultimately, the fuel cell system could be installed in the same chamber as the gasifier so that the hot gas flows straight into the cell. In the fuel cell, a membrane separates the carbon monoxide and hydrogen from the oxygen, promoting an electrochemical reaction that generates electricity without burning the fuel. Because there is no burning involved, the system produces less ash and other air pollutants than would be generated by combustion.

It does produce carbon dioxide (CO2), but this is in a pure, uncontaminated stream and not mixed with air as in a conventional coal-burning plant. That would make it much easier to carry out carbon capture and sequestration (CCS) – that is, capturing the output gas and burying it underground or disposing of it some other way – to eliminate or drastically reduce the greenhouse gas emissions. In conventional plants, nitrogen from the air must be removed from the stream of gas in order to carry out CCS. The concept is described in the Journal of Power Sources.