(SECA) initiative for the development and commercialization of modular, low cost, and fuel flexible SOFC systems. The SECA initiative, through advanced ...
DOE FE DISTRIBUTED GENERATION PROGRAM Mark C. Williams and Bruce Utz US Department of Energy, National Energy Technology Laboratory, PO Box 880, 3610 Collins Ferry Road, Morgantown, WV 265070880 Abstract The U.S. Department of Energy’s (DOE) Office of Fossil Energy’s (FE) National Energy Technology Laboratory (NETL), in partnership with private industries, is leading the development and demonstration of high efficiency solid oxide fuel cells (SOFCs) and fuel cell turbine hybrid power generation systems for near term distributed generation (DG) market with emphasis on premium power and high reliability. NETL is partnering with Pacific Northwest National Laboratory (PNNL) in developing new directions in research under the Solid-State Energy Conversion Alliance (SECA) initiative for the development and commercialization of modular, low cost, and fuel flexible SOFC systems. The SECA initiative, through advanced materials, processing and system integration research and development will bring the fuel cell cost to $400/kilowatt (kW) for stationary and auxiliary power unit (APU) markets. The use of fuel cells is expected to bring about the hydrogen economy. FutureGen is a major new Presidential initiative to produce hydrogen from coal. Solid State Energy Conversion Alliance The SECA Program is the main thrust of the DOE FE DG Fuel Cell Program. SECA is also recognized as part of the Hydrogen Program. Achieving the SECA goals should result in the wide deployment of the SOFC technology in large high volume markets. This means benefits to the nation are large and cost is low, which is the SECA goal. Less expensive materials, simple stack and system design, and high volume markets are the three criteria that must be met by a fuel cell system to compete in today’s energy market. Near zero emissions, fuel flexibility, modularity, high efficiency, simple CO2 capture will provide a national payoff that gets bigger as these markets get larger. The SECA program is dedicated to developing innovative, effective, low-cost ways to commercialize SOFCs. The program is designed to move fuel cells out of limited niche markets into widespread market applications by making them available at a cost of $400 per kilowatt or less through the mass customization of common modules. SECA fuel cells will operate on today’s conventional fuels such as natural gas, diesel, as well as coal, gas, and hydrogen, the fuel of tomorrow. The program will provide a bridge to the hydrogen economy beginning with the introduction of SECA fuel cells for stationary (both central generation and distributed energy) and auxiliary power applications. The SECA program is currently structured to include competing industry teams supported by a crosscutting core technology program. SECA has six industry teams working on designs that can be massproduced at costs that are ten-fold less than current costs. The SECA core technology program is made up of researchers from industry suppliers and manufacturers as well as from universities and national laboratories all working towards addressing key science and technology gaps to provide breakthrough solutions to critical issues facing SECA. Delphi, in partnership with Battelle, is developing a 5 kW, planar, 700 °C – 800 °C, anode supported SOFC compact unit for the DG and APU markets. Delphi is expert at system integration and high volume manufacturing and cost reduction. They are focused on making a very compact and light weight system suitable for auxiliary power in transportation applications. General Electric is
initially developing a natural gas 5 kW, planar, 700 °C – 800 °C, anode supported SOFC compact unit for residential power markets. GE is evaluating several stack designs and is especially interested in extending planar SOFCs to large hybrid systems. They also have a radial design that can simplify packaging by minimizing the need for seals. GE has made good progress in achieving high fuel utilization with improved anode performance using standard materials by optimizing microstructure. SWPC is developing 5-10 kW products to satisfy multiple markets. SWPC has developed a new tube design for their 5 kW units that use flat, high power density tubes. This allows for a shorter tube length and twice the power output compared to their current cylindrical tube. Cummins and SOFCo-EFS are developing a 10 kW product initially for recreational vehicles that would run on propane using a catalytic partial oxidation reformer. The team has produced a conceptual design for a multilayer SOFC stack assembled from low cost "building blocks." The basic cell, a thin electrolyte layer (50 75 micron), is fabricated by tape casting. Anode ink is screen printed onto one side of the electrolyte tape, and cathode ink onto the other. The printed cell is sandwiched between layers of dense ceramic that will accommodate reactant gas flow and electrical conduction. The assembly is then co fired to form a single repeat unit. FuelCell Energy and Acumentrics represent additional industry design alternatives that will enhance the prospects of success of SECA fuel cells for a broader market. SECA Core Research Issues Developing the solid oxide fuel cell which meets both performance and cost targets is a matter of complex trade-offs. Within each sub-system and its components there exist research needs. The needs may be different for the various system alternatives and their design – anode supported, cathode supported, and electrolyte supported; planar, radial tubular. While progress has been made in power density and utilization, the cathode remains an important area of research if low temperatures are to be achieved. To achieve low overpotentials at reduced temperature requires optimization over composition and structure. Mixed ionic and electronic conducting cathodes with sufficient catalytic activity are being considered. Seals are a long-standing issue in some SOFC designs. The requirements on the seal are demanding to ensure thermal cyclability and gas tightness. The use of low-cost metallic interconnects is highly desirable for some designs. SOFC’s and Hydrogen One of the ways in the U.S. to produce hydrogen may be with coal. Coal is a very abundant resource in the U.S. and for energy independence should be used as the primary fuel in the U.S. Coal must be in our future for energy independence. Over 50 percent of the electricity in the U.S. comes from coal, and coal use is increasing. The President recently announced the FutureGen project to produce hydrogen from coal. From the perspective of fuel cells, the goal is to aggregate SECA fuel cells into larger systems and to produce a very high-efficiency fuel cell-turbine hybrid module. The SOFC hybrid is a key part of the FutureGen plants. The highly efficient SOFC hybrid plant will produce electric power and other parts could produce hydrogen and sequester CO2. The hydrogen produced can be used in fuel cell cars and for large SOFC DG applications. The fuel cell or hybrid could operate on syngas or hydrogen and segregation/isolation of CO2 if operating on syngas is possible with some fuel cell designs.
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References (1) Fuel Cells--A Handbook (Revision 4, November 1998), Report Number DOE/FETC-99/1076 (CD). (2) M. Williams, “Status of SOFC Development and Commercialization in the US”, 6th International SOFC Symposium, in Proceedings, pp. 3-9 (1999). (3) M. C. Williams, “Fuel Cells - Realizing the Potential”, Fuel Cell Seminar, Portland, November 1, 2000, in Proceedings Fuel Cell Seminar, pp. (2000). (4) M. Williams, “Energy Decision Magazine Roundtable on DG”, during Electric Power 2000, Cincinnati, Ohio, in Energy Decision, June pp. 26-32, 2000. (5) M. Williams, “Energy Futures: Advanced Fuel cell Power Systems,” Brookings Institute Seminar, “Science and Technology Policy: Current and Emerging Issues,” June 14, 2000. (6) “SECA Workshop Proceedings,” June 1-2, 2000, Baltimore, MD. (7) N. Minh, et. al., in Solid Oxide Fuel Cells VI, S. C. Singhal and M Dokiya, Editors, PV 99-19. p.68, The Electrochemical Society Proceedings Series, Pennington, NJ (1999). (8) J. Thijssen, et.al., Conceptual Design of POX SOFC 5 kW net System, Arthur D. Little, Inc. Report # 71316 (to be published), Cambridge MA (2000). (9) M. Williams and S. Singhal, “Mass-produced ceramic fuel cells for low-cost power,” in Fuel Cell Bulletin, no. 24, pp. 8-11 (September 2000). (10) M. Williams, “Fuel Cells: Realizing the Potential for Natural Gas,” Key Note Address in Proceedings Fuel Cells 2000, Philadelphia, PA, September 27, 2000. (11) M. C. Williams, “Fuel Cells - Realizing the Potential”, Fuel Cell Seminar, Portland, Oregon, November 1-3, 2000, in Proceedings Fuel Cell Seminar, pp. . (12) M. Williams, “Status of SOFC Development and Commercialization in the US”, 7th International SOFC Symposium, Japan, in Proceedings, (2000). (13) M. C. Williams, “Distributed generation fuel cells and power reliability,” #1605, Energy 2001, Baltimore, Md., 2001. (14) M. Williams, “Fuel Cells and the World Energy Future,” in Proceedings PowerGen, Orlando, FL, 2001. (15) David A. Berry, Wayne A. Surdoval, and Mark C. Williams, “The solid state energy conversion alliance - program to produce mass manufactured ceramic fuel cells,” in Proceedings ACS Fuel Cell Symposium, Chicago August 2001. (16) M. C. Williams, “New Direction in the US Fuel Cell Program,” in Proceedings 7th Grove Fuel Cell Symposium, September 11, 2001. (17) Catherine Greenman, “Fuel Cells: Clean, Reliable (and Pricey) Electricity,” The New York Times, May 10, 2001, p. D8. (18) “SECA Workshop Proceedings,” March 29-30, 2001, Arlington, VA. (19) “SECA Workshop Proceedings,” March 21-22, 2002, Washington, DC. (20) “SECA Workshop Proceedings,” April 15-16, 2003, Seattle, WA.
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