  Potential strategies for the development and large-scale application of
renewable energy sources aimed at reducing the usage of carbon-based fossil
fuels are assessed here, especially in the event of the abandonment of such
fuels. The aim is to aid the initiative to reduce the harmful effects of
carbon-based fossil fuels on the environment and ensure a reduction in
greenhouse gases and sustainability of natural resources. Small-scale renewable
energy application for heating, cooling, and electricity generation in
households and commercial buildings are already underway around the world.
Hydrogen (H2) and ammonia (NH3), which are presently produced using fossil
fuels, already have significant applications in society and industry, and are
therefore good candidates for large-scale production through the use of
renewable energy sources. This will help to reduce the greenhouse gas emissions
appreciably around the world. While the first-generation biofuels production
using food crops may not be suitable for long-range fuel production, due to
competition with the food supply, the 2nd, 3rd and 4th generation biofuels have
the potential to produce large, worldwide supplies of fuels. Production of
advanced biofuels will not increase the emission of greenhouse gases, and the
ammonia produced through the use of renewable energy resources will serve as
fertilizer for biofuels production. The perspective of renewable energy
sources, such as technology status, economics, overall environmental benefits,
obstacles for commercialization, relative competitiveness of various renewable
energy sources, etc., are also discussed whenever applicable.
