LESSONS LEARNED FROM THE WORLD'S LARGEST DIGESTER GAS FUEL CELL
Abstract:Increasing energy costs, more stringent air emission regulations, and an interest in exploring emerging energy technologies prompted King County in Washington state to search for new and innovative ways to provide electricity for its wastewater treatment plants. In cooperation with the U.S. Environmental Protection Agency (EPA), FuelCell Energy, Inc. (FCE), CH2M HILL, and Brown and Caldwell, King County (County) is operating the world's largest molten carbonate fuel cell (MCFC) at its South Treatment Plant in Renton, Washington. The 1-megawatt (MW) fuel cell can operate on either natural gas or digester gas. Operation started in April of 2004 as part of a 2-year demonstration project. If successful, the fuel cell will continue to operate and produce energy for the South Treatment Plant after the 2-year demonstration project is completed. The data from this demonstration will provide other municipal wastewater treatment plants with information on fuel cell power systems applicable to their interests and needs.
Fuel cells produce electrical power directly through an electrochemical reaction using hydrogen and oxygen. The hydrogen can be produced from fuels such as natural gas, landfill gas, or anaerobic digester gas, while air provides the oxygen. The fuel cell has an anode and a cathode. When the fuel gas is combined with water, the fuel gas is eventually reformed to hydrogen, which is then fed to the fuel cell anode. Air is fed to the cathode. The reaction of the hydrogen moving from the anode to the cathode through an electrolyte creates electricity. By avoiding the two-step process of conventional combustion technology in which fuel is first burned and then the subsequent heat used to produce power, fuel cells are energy efficient, better for the environment, quieter, and ultimately more cost effective. Unlike combustion technologies, fuel cells have very low emissions of carbon monoxide, sulfur oxides, nitrogen oxides, and non-methane organic carbon. The main product of the fuel cell reaction is water, which discharges in the exhaust gas. Molten carbonate fuel cells are one of the most efficient fuel cell technologies and operate between 40 and 50 percent electrical efficiency. With additional heat recovery, the overall efficiency is typically between 60 and 70 percent.
Document Type: Research Article
Publication date: 2005-01-01
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.
WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Learn about the many other WEF member benefits and join today
- Ingenta Connect is not responsible for the content or availability of external websites