Environmental Engineering Reference
In-Depth Information
Chapter 4
Fuel Cells for Efficient Use of Energy
Tatsuya Kawada
Abstract
This chapter reviews the basic technology and potential application of
fuel cells in the provision of energy, and the fundamental principles which would
underpin the wider use of hydrogen as an energy source for fuel cells ('Hydrogen
Economy'). Hydrogen's strengths and weaknesses as an energy carrier are exam-
ined, and the current development and commercialization of PEFC and SOFC type
fuel cells in transport and domestic combined heat and power systems reviewed.
Keywords
Fuel cells
·
Hydrogen economy
·
PEFC
·
SOFC
·
Combined heat and
power
4.1
Background to Fuel Cell Technologies
Currently, most energy sources are derived from the sun since, excluding energy of
the Earth itself (such as nuclear, geothermal, and tidal), all are the direct or indirect
effects of sunlight now or in the past. Life on earth depends on the solar energy-
driven carbon cycle through photosynthesis which stores part of the energy of sun-
light as chemical energy in a living body. Humanity has mastered how to manipu-
late fire and now can use the energy stored in the ground as fossil fuels laid down in
past eras—firstly coal and subsequently the more user-friendly, oil, natural gas, etc.
Such fossil fuels have supported the modern life of humanity but have changed the
atmosphere's composition and the associated energy balance, leading to the rapid
warming and climate change which are currently underway.
The key issue now is thus how to reduce the use of fossil resources and introduce
alternative 'renewable' or 'sustainable' energies. Modern technologies, such as so-
lar cell and wind turbines can already convert the energy from sunlight to electricity
with higher efficiencies than plant photosynthesis. Electricity is a useful form of
