Chapter 1
Introduction
Chemical fuels are the most widely used energy resource due to their high energy
density and ease of availability. Additionally, storing chemical fuels and
transferring them from one place to another is easier e.g. through pipelines.
Therefore, all the above factors made society heavily dependent on them for its
energy consumption which is increasing every year. Eventually, the increasing
consumption of fossil fuels is leading to increased greenhouse gas emissions.
For example, the global CO2 emission in 2001 was approximately 24.07 gigaton/
year (Gt/yr) which is projected to increase to 40.3 Gt/yr by 2050 and
48.8 Gt/yr by the end of 2100 1. An increase in CO2 emission by almost
two times in the next three decades will pose a serious threat to the environment.
Additionally, the availability of the fossil fuels will also become scarce at
some point. Therefore, it is the need of the hour to search for environmentally
benign and abundant renewable energy resources.
Renewable energy sources e.g. wind energy, hydro-electricity, solar thermal
conversion, solar electricity, solar fuels etc. may serve as viable alternatives to
the fossil fuels 2. Among all renewable energy resources, the biggest source
of the renewable energy is our sun and the immense energy it provides can be
used to power the whole planet. However, we are very far from realizing the
dream of being completely dependent on the sun for our energy requirements.
The challenge lies in utilizing the solar energy in an efficient and economical
way 1, 2. However, concerted and continuous efforts by theoreticians and experimentalists
are being put in order to overcome these challenges. Figure 1.1
shows a model of the workflow for the materials design with mutual feedback
of the experimentalists and theoreticians.
1