The use of alternative energy sources is essential to meet the growing demand for water desalination. Up till now, the expansion of renewable energy sources to run desalination processes at a larger scale is hampered by technical, economic, regulatory and environmental challenges. While medium-scale renewable energy driven desalination plants have been installed worldwide, many are connected to the electrical grid to assure a continuous energy supply for stable operation. This critical review paper focusses on integrated approaches in using renewable energy such as solar and geothermal technologies for water desalination. Innovative and sustainable desalination processes which are suitable for integrated renewable energy systems are also presented, along with the benefits of these technologies and their limitations. The market potential, environmental concerns, regulatory & socio-economic factors are likewise evaluated as well as the need for accelerated development of renewable energy-driven desalination technologies.