Environmental Engineering Reference
In-Depth Information
Low-Cost Nanomaterials
for High-Performance Polymer
Electrolyte Fuel Cells (PEMFCs)
S. M. Senthil Kumar and Vijayamohanan K. Pillai
1 Introduction
Production, storage and deployment of affordable and clean energy is one of the
biggest challenges facing humanity. Although a majority of current energy
requirements is obtained from fossil fuels, the supply is finite and could last only
for a specified period depending on the nature of resources [
1
-
4
]. At the current
consumption rate, coal will perhaps remain only for approximately 150 years,
while oil and natural gas are expected to get exhausted in 50 years [
5
-
8
] assuming
no new resources. The other forms of energy are nuclear, wind, hydrothermal,
biomass, solar and geothermal where each has its own advantages and disadvan-
tages based on the geographical locations of the country and its habitants. Among
the different energy sources, solar energy presents the truly widespread and clean
case where, despite being in its developmental stage, only 0.02 % of available
resource is sufficient to replace fossil fuels and nuclear power together from the
energy sector [
9
,
10
]. However, due to the diffuse nature of solar energy, it
demands a larger area to attain considerable energy density, and is thus not suitable
for use as such in mobile and portable applications. Further, the huge requirement
for landscape necessarily puts this technology into rural places from where the
electricity has to be transported in grids that results in further energy loss. On the
other hand, in today's scenario, the use of fossil fuels for meeting our energy needs
cannot be ruled out due to the lack of other energy resources. However, it poses
severe environmental concern due to the relentless emission of green house gases
(CO
2
). This fact is exacerbated by the low conversion efficiency (25-40 %) of
current internal combustion engines (ICEs) based on the Carnot cycle. While
Carnot cycle efficiency can reach much higher values in an ideal world, only
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