Water is important for life and development. About 1.8 billion people will be living in absolute water scarcity by
2025.Non availability of safe drinkable water is the major source of diseases in the different regions of the world
especially remote rural and coastal areas. About 97% of water on earth is comprised of seawater. Desalination of
saline water is a prominent approach to handle the problem of water scarcity. Conventional desalination technologies
cause economic and environmental problems due to their dependency upon fossil fuels. Solar flash desalination
is one of the best desalination techniques in the developing stages. Solar energy, passive vacuum and recovery of
latent heat of condensation make this system a sustainable option for desalination. In this paper, economic analysis
of the solar thermal desalination system of saline water is presented. The unit cost of desalinated water is found to
be US$ 0.0147 per litre. The energy and emission payback (EEP) period for vacuum chamber and solar collector
has also been presented. The energy payback period of solar collector and vacuum chamber are found to be 1.3
years and 1.5 years respectively. The emission payback period of solar collector and vacuum chamber are found to
be 1.8 years and 2.1 years respectively.