ExxonMobil researchers are talking up the viability of a new fuel cell technology they say could economically capture CO2 emissions from coal and gas power plants without requiring subsidies or carbon taxes.
The developers of these "carbonate fuel cells" say they could represent a breakthrough in making carbon capture and storage (CCS) commercially viable. The power company FuelCell Energy is developing the fuel cells, which so far have only been demonstrated in laboratory tests. ExxonMobil last month announced an agreement with FuelCell to further develop the technology.
Industrial facilities have been able to capture CO2 emissions since the 1970s. But existing CCS technology can consume up to 25pc of the electrical output of a power plant and is difficult to implement on a large scale. Southern Co.'s efforts to build a coal-fired power plant with CCS in Kemper, Mississippi, is now expected to cost $7bn, three times higher than initial estimates.
The carbonate fuel cells, in contrast, would use the exhaust stream of a power plant and natural gas to fuel a process that would generate additional electricity and produce a chemical feedstock called syngas. FuelCell is trying to use the technology to eventually build a 2-3MW demonstration plant that would be paired with a coal-fired power plant.
"This is very clever, this is very unique," ExxonMobil Research and Engineering vice president Vijay Swarup said today in Washington, DC. "You put this on the back end of a power plant, you concentrate the CO2 while creating some byproducts that could be valuable in other processes."
ExxonMobil researchers are focusing on the economics of the technology and how it could be optimized, particularly for use on gas-fired power plants. Swarup said the company is optimistic about carbonate fuel cells but conceded researchers "have to be ready for it not to work." Deploying the fuel cells on a commercial scale is still likely years away, he said.
"We will get there when we get there, or we will not get there," he said at an event hosted by the think tank the Center for Strategic and International Studies. "Either way we want to understand why or why not."
Swarup declined to say how much money ExxonMobil was investing in the partnership or on CCS research generally.
FuelCell president Chip Bottone estimates that electricity from a 500MW coal-fired power plant paired with about 400MW of carbonate fuel cells would cost about $50/MWh, which he said was a "reasonable price by most standards." The average wholesale price of electricity in the PJM Interconnection, the largest US electrical grid, was $36.16/MWh last year.
The addition of carbon taxes would help reduce the price of electricity from the fuel cells but may not be necessary to advance the technology, Bottone said.
