Page 17 - Materials Chemistry, Second Edition

2 A. Singh et al.

Singh 2011). The production of sustainable energy based on renewable sources is a
challenging task for replacing the fossil-based fuels to get cleaner environment and
also to reduce the dependency on other countries and uncertainty of fuel price
(Singh and Olsen 2012, 2011; Pant et al. 2012). A worrying statistic is that the
global production of oil and gas is approaching its maximum and the world is now
finding one new barrel of oil for every four it consumes (Aleklett and Campbell
2003). All these serious concerns related to energy security, environment, and
sustainability have led to a move toward alternative, renewable, sustainable,
efficient, and cost-effective energy sources with lesser emissions (Prasad et al.
2007a, b; Singh and Olsen 2012).
The life cycle assessment (LCA) of renewable energy sources is the key to
observe their sustainability. There is a need to conduct LCA of renewable energy
production system on the basis of their local conditions, as one energy source
cannot be sustainable for all geographical locations, due to variations in resources
availability, climate, environmental, economical and social conditions, policies,
etc. Therefore, LCA can be used as a tool to assess the sustainability of various
energy sources for different locations. LCA techniques allow detailed analysis of
material and energy fluxes on regional and global scales. This includes indirect
inputs to the production process and associated wastes and emissions, and the
downstream fate of products in the future (Singh et al. 2011). LCA studies vary in
their definition of the various criteria, such as, scope and goal, system boundaries,
reference system, allocation method. LCA studies of renewable energy sources
calculate the environmental impact and can relate the results against sustainability
criteria. The present chapter is an effort to highlight the importance of LCA of
renewable energy sources to get a more holistic perspective of their environmental
sustainability.

2 Renewable Energy Sources

The most common renewable energy sources are presented in the Fig. 1. Each
renewable energy source is performing differently; one could be best option for
one location/purpose/season and could not perform with that efficiency at another
location/purpose/season. The solar energy sources are best in remote or under
developed areas having bright sunshine (Jayakumar 2009). Windmills are best
suited near sea shore, as there winds are enough strong to get decent production of
energy. Similarly, tidal, hydroelectric, geothermal, and ocean thermal energies
have their importance. Among the renewable energy sources, biofuels are the most
popular renewable energy source because of the availability of raw material
(biomass), everywhere and round the year and also due to its suitability in
transport vehicles and industries. The detailed description of different biofuels is
published by Nigam and Singh (2011).