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Monday, October 23, 2006 A Practical Fuel-Cell Power PlantGE's advance allows for a solid-oxide fuel cell to use coal-based fuels at costs approaching that of conventional power plants. By David Talbot
One of the most efficient ways to produce power at future coal-gasification power plants is with solid-oxide fuel cells, which use the hydrogen from the gas stream to generate electricity through chemical reactions. This is more efficient than simply combusting the gas stream from coal gasification. And unlike other types of fuel cells, the solid-oxide variety can operate at very high temperatures and efficiencies, and be scaled up to provide cities with power. But among the various challenges to developing the technology, manufacturing cost has been a potential deal breaker. Now, researchers at GE have demonstrated a manufacturing method that assembles layers of ceramic and electrolyte materials cheaply so that the final product can be built for about $800 a kilowatt, which starts to approach the $500-to-$550-per-kilowatt cost of building a conventional gas-fired power plant. GE's six-kilowatt prototype achieves 49 percent efficiency in converting fuel into electricity, which compares favorably with the 35 percent efficiency of conventional coal-burning power plants. "I do believe GE has established a new state of the art," says Wayne Surdoval, technology manager for fuel cells at the National Energy Technology Laboratory, part of the U.S. Department of Energy, which is funding this project and others aimed at producing better solid-oxide fuel cells. "The bottom line," he adds, is that the GE prototype "is a particularly inexpensive fuel cell to make. Basically, you are using simple manufacturing techniques using fairly inexpensive materials in the cell." Surdoval likens the process to making pizza dough. Three sets of materials--representing the two electrodes and one electrolyte that make up each layer of a fuel cell--are mixed and put through two rollers that squeeze them. "You have three different doughs, you flatten each one, then layer them, then flatten them," he explains. "Then basically, you bake it." The process paves the way for mass manufacture, according to Kelley Fletcher, the advanced-technology leader for sustainable-energy programs at GE Global Research, in Niskayuna, NY. "People have made fuel cells that make more power, and people have also made ones that have done this efficiency level," he says. "But to do so in one package, and at the cost estimate that we have done, is the real achievement here." Previous prototypes have cost thousands of dollars per kilowatt to manufacture, he says.
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A Cool Fuel Cell
08/04/2008
Massachusetts Institute of Technology
Comments
MarkShapiro on 10/23/2006 at 3:14 PM
13
Better yet, if the reliable DC electric output could be used directly for electronic devices (such as for a computer server farm), you avoid all the costs and losses of converting to AC and back to DC.
eminentas on 10/23/2006 at 4:17 PM
2
This is the energy used from manufacturing the components going all the way up to having the system operating and producing some type of energy (electricity or heat basically).
It would be interesting to evaluate the amount of energy involved on producing a unit of SOFC, let’s say 1 kWe, and compare with other technologies.
I believe there is a huge amount of energy involved on preparing the wafers of ceramic electrodes and cocking them at high temperatures (usually above 1000°C).
A similar case occurs on making the silicon ingots for solar photovoltaic cells that at the end will be less than 15% efficient.
The good point for SOFC is the possibilities for heat recovery and co-generation from which an important amount of high quality heat can be recovered and utilized for space heating, process heat, process steam or moving an adsorption chiller for A/A.
On this way we could reach easily 75% up to 85% efficiencies. This is very good.
Another point is to include the efficiency for making the syngas from coal.
An alternative approach is the use of conventional heating oil (with very low sulfur content) directly on SOFC, without pre-reforming, since the infrastructure for using heating oil is already in place.
At the SOFC operating temperature it is possible to use this fuel.
Some Japanese,UK and American universities support this route on SOFC.
Based on this fuel, the deployment of residential and commercial SOFC would be easily enabled.
49% fuel cell efficiency is a very good figure and if we could place on top on this a heat recovery system even better.
TaffyDownUnder on 10/26/2006 at 8:06 PM
2
asdar on 11/01/2006 at 4:08 PM
64