Can natural gas-SOFC combo be cheapest route to cleaner electricity? | The American Ceramic Society

Can natural gas-SOFC combo be cheapest route to cleaner electricity?

Credit: Thomas Adams

Credit: Thomas Adams

Two researchers at MIT say they have what will be “the lowest price option” for power generation in the future if a carbon tax is every levied in the United States (as long as the tax is $5 – $15 per metric ton of emitted CO2).

The duo – Thomas Adams and Paul Barton – have proposed a novel electricity generation process that weds natural gas and solid oxide fuel cells using off-the-shelf technology, and have applied for a patent for their concept. A paper on their work has been printed in the Journal of Power Sources.

Their process contains a steam reformer that prepares the gas for use within the fuel cells. The reformer and water-gas shift reactor creates a fuel mix absent carbon monoxide, thus avoiding the problems created by carbon deposition issues in SOFCs when CO is present. CO2 is generated, but they say it will be “mostly pure” and can be captured with very little energy penalty using a multistage flash cascade process. High-purity water is another byproduct.

Adams and Barton developed the concept while looking at possible “clean-coal” approaches, and they admit their system could also work with pulverized coal. But, the relatively greater abundance of natural gas and its smaller amount of CO2 emissions (an MIT news story reports that existing natural-gas power plants produce one-third to one-half the CO2 of coal-burning plants) provide two strong reasons for using this fuel.

And price – under the right circumstances – could be a third reason. Adams and Barton developed and used a computer simulation methodology to analyze the relative costs and performance of their system versus other existing or proposed generating systems, including natural-gas or coal-powered systems incorporating carbon capture technologies.

They found that even if the cost of fuel cells remains more than double the DOE’s target for 2010, their SOFC system has the lowest lifecycle costs of electricity produced, even though the up-front capital costs could be three to four times greater than for natural gas or coal combustion systems.

The simulation even indicated that the lifecycle cost of this novel system is lower than that of a combined-cycle natural gas plant, even without carbon pricing. They say that even with a carbon tax around $5 to $10 per ton, their system would be cheaper than coal plants, currently the lowest-cost option for electricity generation.

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