The growing global demand for clean and sustainable energy has led to the exploration of unconventional renewable energy sources. One such emerging technology is salinity gradient power, also known as blue energy, which harnesses the chemical potential difference between freshwater and seawater. This paper discusses the principles, methods, efficiency, applications, and future prospects of salinity gradient power. The study highlights pressure retarded osmosis (PRO) and reverse electro dialysis (RED) as primary conversion techniques and evaluates their potential in addressing global energy needs.