The Offshore Pumped-Storage (OPS) system is a patent-pending(Subhydro) concept for a utility-scale electricity storage solution. The concept involves a subsea installation of man-made reservoirs for the generation and storage of electric energy through a pump turbine - generator unit. OPS is a safe and environmentally friendly energy storage for coastal regions and islands and offers a matchless solution for offshore oil & gas platforms. OPS enables the use of more variable energy sources such as wind, ti dal and solar power. OPS has a global potential to reduce dependency on fossil fuel power generation and on capital intensive grid connections to remote locations