Large Stationary Power Generation

SOFCs can also operate with a number of other hydrocarbon fuels including natural gas and clean coal gas by producing hydrogen through an internal or external reforming process. Applications include large stationary power generation and CHR... 

As stated earlier, fuel processing technology from large chemical installations has been successfully transferred to small compact fuel cell units to convert pipeline natural gas, the fuel of choice for small stationary power generators. The technology for converting natural gas is described later in this section. 

Phosphoric acid fuel cells (PAFC) use liquid phosphoric acid as an electrolyte - the acid is contained in a Teflon-bonded silicon carbide matrix - and porous carbon electrodes containing a platinum catalyst. The PAFC is considered the "first generation" of modern fuel cells. It is one of the most mature cell types, the first to be used commercially, and features the most proven track record in terms of commercial applications with over 200 units currently in use. This type of fuel cell is typically used for stationary power generation, but some PAFCs have been used to power large vehicles such as city buses. 

Stationary power generation on a large scale may use either low- or high-temperature fuel cell systems, and several systems rated at up to a few hundred kW have been operated (Barbir, 2003 Bischoff et ah, 2003 Veyo et ah, 2003). The systems comprise the basic units of PEMFC, MCFC or SOFC as described in Chapter 3, combined with fuel preparation and exhaust clean-... 

PAFCs have been available for decades, producing a maximum 5 MW of power for a large stationary cell stack. Current models, produced by UTC Power, have a lifetime of 40,000 h. Multiple industrial companies including UTC Power (US) have been developing PAFCs, but mostly for stationary power generation the most current interests are to increase the lifetime to 80,000 h. 

Figure 1.17 presents some examples of stationary power generators Figure 1.17(a) shows small-seale systems and Figures 1.17(b) to 1.17(e) show large-scale utility plants. 

Scale and use Several kW Automobile, stationary Several 100 kW Distributed power generation for industry Several 100 kW Large scale power generation plant Several kW-100 kW Distributed power generation for industry and stationary APU for automobile... 

During the past three decades, major efforts have been made to develop more practical and affordable designs for stationary power applications. Today, the most widely deployed fuel cells cost about 4,000 per kilowatt compared to diesel generator costs of 800 to 1,500 per kilowatt. A large natural gas turbine can be even less. 

Fuel cells are an important technology for a potentially wide variety of applications including micropower, auxiliary power, transportation power, stationary power for buildings and other distributed generation applications, and central power. These applications will be in a large number of industries worldwide. 

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