In Phase III, the work will focus on the continued development of cell and stack technology via design and materials development with emphasis on performance, reliability, cost, and manufacturing enhancement. This development will be supported through the fabrication, testing, and post-test analyses of the fuel cells and fuel cell stacks, culminating in the test of a ≥ 30kW stack tower for 3000 hours or more. The stack tower test shall meet DOE cost goals (≤ $700/kW power block, ≤ $175/kW stack, 2007 $) and endurance goals (≤ 1.5%/1000 hours steady-state degradation). With successful stack tower test, FCE will fabricate and test a SOFC-based small-scale proof-of-concept module system, including the SOFC stacks, mechanical balance of plant (BOP), and electrical BOP. Cost and IGFC system performance analyses will be updated as the work progresses.
FCE relies upon state-of-the-art planar SOFC technology provided by VPS. A cell is composed of a Ni-YSZ anode, YSZ electrolyte, and a proprietary perovskite cathode, and it has an electrochemically active area of 550 cm2. Cells are manufactured by tape casting, screen printing, and co-sintering(TSC). The repeat-unit building blocks of the fuel cell stack consist of a cell and coated low-cost stainless steel interconnects. The repeat units are assembled into stacks, which are in turn aggregated into modules of the desired power rating.
The mission of the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) is to advance energy options to fuel our economy, strengthen our security, and improve our environment. With the Solid Oxide Fuel Cells (SOFCs) program and systems coordination from the Solid State Energy Conversion Alliance (SECA), DOE/NETL is leading the research, development, and demonstration of SOFCs for both domestic coal and natural gas fueled central generation power systems that enable low cost, high efficiency, near-zero emissions and water usage, and carbon dioxide (CO2) capture.
FuelCell Energy, Inc. (FCE), in cooperation with the SOFC technology developer Versa Power Systems (VPS), is one of multiple SECA Industry Teams developing SOFC technology for Integrated Gasification Fuel Cell (IGFC) systems. VPS became a wholly owned subsidiary of FCE in late 2012. FCE is currently engaged in the third phase of the project subsequent to meeting the fuel cell test and system cost metrics in the prior phases.
Earlier project phases focused on cell and stack research and development with emphasis on SOFC performance enhancement (power density, fuel utilization, and degradation), cost reduction, and scaling the cells and stacks to larger sizes. Conceptual and preliminary Baseline IGFC System (>100 megawatts [MW]) designs were developed and analyzed, and FCE completed a conceptual design of the 250-1000 kilowatt (kW) proof of concept (POC) fuel cell module system. Such modules may serve as market-entry commercial products as well as the building blocks of larger systems. Stack tests conducted in accordance with DOE guidance culminated each phase, and data from these tests were used to estimate the performance and cost of the SOFC stacks and Baseline IGFC System. In 2010, FCE met the SECA highvolume cost targets for the SOFC stack and IGFC power block of $175/kW and $700/kW, respectively (2007 dollars [$]).
The SOFCs program will ultimately enable fuel cell-based near-zero emission coal plants with greatly reduced water requirements and capable of capturing 97 percent or greater of carbon at costs not exceeding the typical cost of electricity available today. Achievement of this goal will have significant impact for the nation given the size of the market, expected growth in energy demand, and the age of the existing power plant fleet. It will also provide the technology base to enable grid-independent distributed generation applications. Federal funding support of this research is appropriate given the game changing nature of the technology, accompanied by risks higher than the private sector initially can accept. In parallel, SECA Industry Teams will take advantage of the inherent scalability and fuel flexibility of SOFCs in seeking nearer-term, smaller-scale commercial applications for this efficient, environmentally-friendly technology, which has less risk than a first-of-a-kind full-scale IGFC system. Success in these spin-off applications (e.g., distributed generation, military, etc.) will further SOFC technology advancement and widespread commercial deployment through the resultant manufacturing and operational experience.
Goals and Objectives
The overall goal of this project is the development of SOFC cell and stack technology suitable for use in highly-efficient, economically-competitive central generation power plant facilities fueled by coal synthesis gas (syngas). The supporting objective in Phase III is the validation of the performance and robustness of stacks and scaled stack arrays suitable for use in large-scale power generation systems such as IGFC systems, where reliable, fail-safe operation is of paramount importance.
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