Requirements 5a and 5b

Requirement 5a:
Seek other applications in which fuel cells are being utilized to recover landfill gas. I know there is one in the Seattle area, and there may be a PAFC in use in Portland. For each example that you find,

i. Characterize the gas supply.

ii. Identify System Efficiencies.

iii. List hardware specifications (i. e. type and size of fuel cell, manufacturer information, etc.).

iv. Compare your determined efficiencies with the thermodynamic ideal efficiency.

Requirement 5b:
Find an actual application for a SOFC and obtain as much data about its operation as possible (gas flow in, gas flow out, power output, cooling air / water flows, equipment, operation, fuel requirements, etc.)

Fuel Cell Applications

Braintree Electric Light Department -- The fuel cell uses methane from the landifll to produce 200 kilowatts of electricity at 480 volts. This should power around 75 houses in the town of Braintree. The fuel cell was initially tested at the Penrose Landfill in Sun Valley, California but was then moved to Connecticut. One of the benefits of the the fuel cell was that the residents of the city did not have to construct and expensive flare to deal with their excessive methane from their landfill that would have cost around $ 500,000.00. The fuel cell was constructed by ONSI (now UTC Fuel Cells). ONSI also developed a method for cleaning the gas before it is used in the fuel cell. The fuel cell itself is a PC25 Fuel Cell Power Plant manufactured by UTC Fuel Cells. UTC reports that the fuel cell has 37% electrical efficiency and up to 80% efficiency if the heat is recovered. The Braintree Electric Light Department got a $ 200,000.00 grant from US Department of Energy and a $ 100,000.00 grant from the Massachusetts Division of Energy Resources to help cover the costs. The project will cost around $1.5 million overall.

City of Portland -- This fuel cell uses the methane from the treatment of Portland's waste water. The fuel cell powers one of the buildings in the treatment facility. At one point in 1999, it was producing 175 kilowatts per hour, enough electricity to power around 125 homes. To fund the project, which would have cost $1.3 million, the City of Portland got a number of grants and tax credits. Among these were a $ 200,000.00 grant from the U.S. Department of Defense, a $ 247,000.00 rebate from PGE, and a tax credit from the Oregon Office of Energy worth $ 224,000.00. The project has a projected 8.6 year payback period. The Columbia Boulevard Wastewater Treatment Plant, where the fuel cell is located, processes approximately 80 million gallons of sewage everyday. All of this sewage produces approximately one million cubic feet of gas, commonly known as Anaerobic Digester Gas, or ADG. The fuel cell will use about five percent of this gas. The gas is also sold to the Malarkey Roofing Company for use in a boiler. The remaining 54 percent of the gas is flared off at the site. The fuel cell itself is a PC25 Fuel Cell Power Plant manufactured by UTC Fuel Cells. This fuel cell is identical to the fuel cell used at the landfill at Braintree. The efficiency is around 37% if the heat isn't recovered and up to 80% if the heat is recovered.

Efficiency -- Ideal thermodynamic efficiency is something that even nuclear power plants have a hard time apporaching. Nuclear power plants, for example, have an efficiency of about 30%. If these were idea engines, their efficiency would be around 40%. The fuel cells discussed above are very versatile and can be used in a number of ways. When run at the coldest, and least efficient setting, the fuel cell is around 40% effective. Ideally, a fuel cell that dealt with similar temperature ranges would have an efficiency of around 46%. The fuel cell has an efficiency very close to ideal efficiency. When run at higher temperatures, the fuel cell is even more efficient. The manufacturer claims efficiencies of up to 80%. Ideally, the fuel cell would be around 81.2% efficient. This means that the fuel cell is very efficient, especially when run at higher temperatures.

SOFC Application

The Siemens Westinghouse 25kW Tubular Solid Oxide Fuel Cell -- This solid oxide fuel cell (SOFC) has been designed in a revolutionary tubular shape that allows the celles to be connected together in series to produce more electricity. The tubes are 50 cm long and around 1.6 cm in diameter. For maximum efficiency, the tubes must be maintained at 1000° C. In optimum conditions, each tube will generate approximately 65 W DC. The tubes can be bound together with nickel felt, which will create an electrical connection between the individual cells. Air is circulated through and around the tubes to allow the reaction to take place and to use the heat from the reaction to produce more power.

That was a lot of reading. Unwind here!