Page 325 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

312 Renewable Energy Devices and Systems with Simulations in MATLAB and ANSYS ®
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should be costing less than $1700/kW by the year 2020. A 100 kW to 3 MW CHP-distributed gen-
eration fuel cell system operating on natural gas needs to have an efficiency greater than 50%, an
energy efficiency of 90%, and the installed cost should be less than $1500/kW by the year 2020.
PEMFC technology continues to be the most popular type of fuel cell being used in various appli-
cations and also with regard to unit shipments. This can be attributed to its suitability of use for both
small- and large-scale power generation. In high power stationary applications greater than 500 kW,
the picture is distributed more evenly between PEMFC, MCFC, and SOFC. Stationary fuel cells are
emerging as alternative to combustion heat engines for the production of electric power and for the
cogeneration. Although PEMFCs have been used in many stationary power generation applications,
high-temperature fuel cells show tremendous promise. By combining with gas turbine as a hybrid
system, efficiencies greater than 65% could be achieved.
Fuel cells for prime power applications continue to be dominated by three companies: FuelCell
Energy (MCFC, 300 kW+), Bloom Energy (SOFC, 200 kW+), and Doosan Fuel Cell America
(PAFC, 400 kW+). Ballard Power Systems, in the 1990s, pioneered the advancement of PEMFCs for
transportation applications. Since the overall technology of fuel cells did not advance as predicted,
Ballard diversified its market to other applications such as distributed power generation, material
handling, and backup power. Ballard continues to sell a small number of its PEMFC ClearGen™
units and the company commissioned a 1 MW system at the headquarters of Toyota USA at the end
of 2012. In early 2013, it also announced the development of 175 kW systems to run using hydrogen
produced from biomass gasification. The technology of high-temperature MCFC has been evolving
over the past 30 years. A leading U.S. manufacturer, FuelCell Energy, pioneered the development of
250 kW MCFC–based system in partnership with the U.S. Department of Energy. FuelCell Energy
delivered its first commercial unit in 2003, and several units are now operating at more than 50 facili-
ties worldwide. Presently, FuelCell Energy produces 300 kW, 1.4 MW, and 2.8 MW fuel cell power
plants. These systems offer CHP capabilities for use in industrial processes or facility heating and
absorption chilling [33]. There is a significant interest by the academia and industry to advance the
technology of SOFC. Initially, the focus was on tubular type cells, but presently the focus is mainly on
high-efficiency planar-type SOFC. Bloom Energy is one of the major suppliers of SOFC-based power
generation system and has installed these systems at several industrial and commercial locations.
Bloom Energy is producing 262 kW, 210 kW, and 110 kW systems [34]. There are other manufac-
turers such as Delphi, Halder Topsoe, and Ceramic Fuel Cells, all working on lower power systems.

12.9 SUMMARY
In this chapter, types of fuel cells, the control characteristics, and power conversion strategies for
transportation and stationary power generation are discussed. PEMFCs are being used for automo-
tive propulsion applications and are better suited as an automotive APU if pure hydrogen is the cho-
sen fuel source, without onboard reforming. SOFC could also be used as an APU, which does not
need pure hydrogen. SOFC and MCFC are mainly used for stationary power generation. The high
efficiency of fuel cells along with high-quality heat has found ways for CHP generation as well as
heating options, thus increasing the overall efficiency of the system [35].
Power electronics is an enabling technology for the advancement of fuel cell–based propulsion
systems and fuel cell power generation systems. The power converters match the fuel cell voltage to
the traction inverter input voltage to produce the required output voltage and frequency for propul-
sion and power generation applications. Progress has been made in the area of power electronics
to reduce the cost and volume and improve the efficiency of the system. In addition to the fuel cell
stack itself, the cost of power electronics has also to be considered. But the technology has signifi-
cantly advanced to such an extent that the power electronics system costs considerably less than the
similarly rated fuel cell stack and its balance of plant. In spite of all the challenges associated with