It relates to a pumped hydro energy storage system and method. In particular, the system and method use a high-density fluid or a combination of a high-density fluid and a lower-density fluid, such as water, to increase power output. The hydro energy storage system further includes fire extinguishing functions for putting out proximately located fires. Conventional pumped hydro energy relies on water flowing from an upper reservoir to a lower reservoir through a penstock. The water then turns a turbine to generate electricity and send it to the grid. Water is pumped up the penstock to recharge the upper reservoir. Pumped hydro energy storage, since it has, besides a turbine, a pump to recharge the system, provides controllability and reliability. This stabilises the supply and demand imbalances inherent in traditional renewable energy sources. Furthermore, an essential consideration for conventional hydro power energy systems and pumped hydro storage is the footprint required by the reservoirs. The present system is directed to a small footprint pumped hydro energy storage system and method with high power output.