Fuel Cells

PAFC

There are well over 200 phosphoric acid fuel cells in service and much operating experience has been obtained. These fuel cells have been installed at medical, industrial, and commercial facilities throughout the country and the 200-kW size is a good match for distributed generation applications. The operating temperature is about 400°F, which is suitable for co-generation applications.

Developers of PAFC are targeting commercial and light industrial applications in the 100-200 kW power range, for both electric-only and cogeneration applications. For such applications, PAFC has demonstrated multiple favorable characteristics to date, including:

• Packaged systems with extremely high reliability (some have operated in the field for >9,000 hours of continuous service)
• Very low noise and vibration
• Negligible emissions
• High electrical efficiencies (36 - 42%)

MCFC

The high efficiency and high operating temperature of MCFC units makes them most attractive for base-loaded power generation, either in electric-only or cogeneration modes.

Potential applications for MCFCs include:

• Industrial
• Government facilities
• Universities
• Hospitals

SOFC

Solid oxide fuel cells are being considered for a wide variety of applications, especially in the 5-250 kW size range:

• Residential cogeneration
• Small commercial buildings
• Industrial facilities

Larger sizes in the multi-megawatt range are being considered, and would be used primarily for base-loaded utility applications.

PEMFC

PEMFC technology development has been driven in large part by the automotive sector, where the PEMFCs have a compelling advantage over other fuel cell technologies in terms of their size and startup time (see Table below).

Comparison of Fuel Cell Technologies

Many of these attributes are also attractive for stationary markets, and have encouraged developers to simultaneously develop products for this sector. Products are being developed at the large end for commercial-sized power generation (most prominently as Ballard's 250 kW unit), and at the small end for residential power generation (most notably by Plug Power's 3-5 kW and below sized units). Practical considerations dictate that these units be able to operate on natural gas. As with all fuel cell technologies, the need to reject system heat (in the form of hot water) makes them particularly attractive for cogeneration, which is included in almost all products currently under development.

PEM fuel cells are currently being developed for a broad range of applications including:

• Automotive
• Residential (<10 kW), both with and without cogeneration functionality
• Commercial (10 - 250 kW), both with and without cogeneration functionality
• Light industrial (250 kW and below), both with and without cogeneration functionality
• Portable power (several kW and smaller)