Page 324 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

Power Conversion and Control for Fuel Cell Systems in Transportation 311

be implemented to operate the front-end converter to operate the fuel cell at MPP under all operat-
ing conditions for the best utilization of the fuel. An example of perturb and observe (P&O) MPPT
®
through a boost converter implemented using MATLAB is explained in Appendix 12A.
12.8 PRESENT STATUS AND FUTURE STRATEGIES

Despite the challenges in developing fuel cell systems, significant progress has occurred, espe-
cially over the last decade, due to government funding and private sector investment. In 2014, the
fuel cell industry grew by almost $1 billion, reaching $2.2 billion in sales, up from $1.3 billion
in 2013. Major increases were spurred by fuel cells for material handling (the United States) and
large-scale stationary power unit sales by U.S. companies and residential fuel cells in Japan [30].
In addition, large commercial and industrial buildings as well as data centers are using fuel cells for
reliable power or CHP. Although fuel cell technology has shown great promise, the FCVs continue
to remain merely as demonstration vehicles or limited use vehicles. This is because of the issues
related to cost, manufacturing, robustness of the technology, hydrogen production, and hydrogen
infrastructure. However, automakers have renewed their interest in FCVs. In 2015, at least five auto
companies including Honda, Toyota, and Hyundai launched their FCVs. The Honda FCV will seat
five persons and will have a range greater than 300 miles (480 km). Honda developed a fuel cell
concept in 2006 that became available on a lease-limited basis in 2008 as the Honda FCX Clarity,
a four-seat sedan. About 200 of these vehicles are on monthly lease in southern California, where
there are hydrogen refueling stations. Nissan signed an agreement in January 2013 with Daimler and
Ford to build a common fuel cell system and hopes to release an FCV in 2017 [31]. Toyota Mirai
FCV is already available in California. Its range is about 300 miles (480 km), refueling will take
about 5 min, and fuel is included for the first 3 years of ownership. The power train has an eight-
year/100,000 mile (162,000 km) warranty to allay early-adopter concerns.
The future of FCVs depends on the advancement of the battery technologies for EVs. If the
lithium ion or lithium air batteries advance sufficiently to provide a range of about 500 miles, and
also the charging infrastructure receives continued interest and investment, the EVs could become
dominant and there would be less interest in FCVs. Also, if the EV batteries are charged using
renewable energy sources, there will not be any emissions due to the charging of EVs. However,
with the advancement of PEMFC and SOFC technologies, the fuel cell systems could be used as
range extenders instead of the ICE-driven generators in series hybrid vehicles. The batteries in these
vehicles could also be charged by connecting to an external power source. These PFCVs, consisting
of a smaller fuel cell and a larger battery (battery dominant), may be the future direction for FCVs.
Using a compressed hydrogen cylinder for onboard charging would lead to a zero-emission vehicle
with a range greater than 500 miles (800 km). The fuel cell unit in these vehicles could also provide
backup or sustained heat and power to a residence. The hydrogen infrastructure is not stringent for
the PFCVs. If the hydrogen is generated using renewable energy and the battery is charged by the
power generated by the renewable energy sources, in addition to the pure EVs, the PFCVs could
take up a significant share of the auto market. The pure fuel cell (or fuel cell–dominant) vehicle
could still play a role in certain geographic locations where abundant amount of hydrogen is pro-
duced using renewable energy sources and for specialized vehicles, buses, etc.
In spite of the advancement in research and technology over several years, high manufacturing
cost, long-term durability, weight, and volume are still the major hurdles to commercializing the fuel
cell–based systems. By the year 2020, technical targets set by the U.S. Department of Energy for
integrated PEMFC power systems and fuel cell stacks operating on direct hydrogen for transporta-
tion applications for an 80 kW system are power density of 850 W/L, specific power of 650 W/kg,
and a cost of $30/kW. These targets exclude hydrogen storage, power electronics, and electrical
drive [32]. The U.S. Department of Energy has also set goals for residential and commercial fuel
cells. A 1–10 kW residential CHP-distributed generation fuel cell system operating on natural gas
needs to have an efficiency greater than 45%, an energy efficiency of 90%, and the 10 kW system