Operating A Fuel Cell Using Landfill

C. E. Trippel, Northeast Utilities Service Company J. L. Preston, Jr., and J. Trocciola, International Fuel Cells Dr. R. Spiegel, U.S. Environmental Protection Agency

An ONSIPC25™, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Handers Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications to simplify the GPU design and demonstrate reliability of the entire system.

In 1992, the EPA contracted with IFC to design and build a landfill gas pretreatment unit (GPU) that would allow landfill gas (LFG) to be used by a fuel cell. Upon successful demonstration of the GPU, the fuel cell was installed at the Penrose Landfill in Los Angeles to demonstrate the system operation. The energy recovery system operated for approximately 3 months, concluding operations in February 1995. In order to verify operation on a different composition LFG and in different climatic conditions, the energy recovery system was shipped to the East Coast. Discussions between all parties resulted in the Town of Groton landfill being chosen as a site to continue operation of the fuel cell and GPU system. The fuel cell and GPU are currently owned by the EPA. CL&P is the funding source for the project and providing the engineering, design, and construction for the installation as well as the operation and maintenance for the 12-18 month demonstration period. IFC is providing technical expertise for the operation of fuel cell and GPU system. The Town of Groton is providing the site, the collected LFG and operation of an existing landfill gas flare at no cost to CL&P.

The LFG is collected from a 45 acre closed landfill. Based on the estimated volume of solid waste in the Groton landfill, a calculated 204 million cubic feet of LFG would be produced annually. Prior to the installation of the fuel cell system at Groton, the LFG was collected and burned in a flare at a rate of approximately 400 cubic feet per minute (cfin). The fuel cell system uses a maximum of 80 standard cfm of landfill gas while the remaining gas continues to be burned by the flare. Where landfill gas is emitted into the atmosphere without recovery and use, methane has a global warming potential much greater than that of carbon dioxide. Some of the non-methane constituents of LFG, such as hydrogen sulfide, are odoriferous and potentially harmful to the environment.

The fuel cell emissions are primarily water vapor and carbon dioxide. Emissions of NOx and SO„, which result from the combustion of LFG, are virtually eliminated. Due to its higher efficiency, the quantity of C02 emitted from the fuel cell is less than the amount created through combustion conversion electrical generators such as the combustion turbine and internal combustion engine. A comparison of typical emission rates is as follows:

Turbine 0.00153 0.00017 1.96

Combustion

Typical Emission Rates (lbs/kWhr) Internal Combustion Engine

Fuel Cell 0.00001 0

0 0

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