Using fuel cells to capture power plants' CO2 lowers emissions and boosts power generation. Image credit: ExxonMobil.ExxonMobil Corporation and FuelCell Energy Inc. will develop technology that uses carbonate fuel cells to capture carbon dioxide from power plants.

According to ExxonMobil, two years of comprehensive laboratory tests have demonstrated that the integration of two existing technologies—carbonate fuel cells and natural gas-fired power generation—can capture carbon dioxide more efficiently than existing scrubber technology. The potential breakthrough comes from an increase in electrical output using the fuel cells, which generate power, compared to a nearly equivalent decrease in electricity using conventional technology.

To capture CO2, power plant exhaust is directed to the fuel cell, replacing air that is normally used in combination with natural gas during the fuel cell power generation process. As the fuel cell generates power, the carbon dioxide becomes more concentrated, allowing it to be more easily and affordably captured from the cell’s exhaust and stored.

The resulting net benefit has the potential to substantially reduce costs associated with carbon capture for natural gas-fired power generation, compared to the expected costs associated with conventional separation technology, ExxonMobil says. A key component of the next phase of research will be to validate initial projected savings of up to one-third.

“Carbon capture with carbonate fuel cells is a potential game-changer for affordably and efficiently concentrating carbon dioxide for large-scale gas- and coal-fired power plants,” says Chip Bottone, president and chief executive officer of FuelCell Energy. “Ultra-clean and efficient power generation is a key attribute of fuel cells, and the carbon-capture configuration has the added benefit of eliminating approximately 70% of the smog-producing nitrogen oxide generated by the combustion process of these large-scale power plants.”

The partnership between ExxonMobil and FuelCell Energy will initially focus on how to further increase efficiency in separating and concentrating carbon dioxide from the exhaust of natural gas-fueled power turbines. If milestones are reached as expected, a second phase will more comprehensively test the technology for one to two years in a small-scale pilot project prior to integration at a larger-scale pilot facility.