The U.S. aims to achieve net-zero emissions by 2050, requiring 700 to 900 GW of additional capacity, a substantial portion of which will be supplied by renewables. However, the challenge lies in storing excess renewable energy, particularly from sources like solar power. In 2024, California curtailed over 3 million MWh of solar energy due to grid limitations. To address this, the DOE allocated $3 billion for Battery Energy Storage Systems grants, supporting projects with up to four hours of storage. Beyond short-term storage, long duration energy storage (LDES) has become a priority. Mechanical energy storage solutions such as Pumped Hydro and Compressed Air Energy Storage (CAES) are being considered. Pumped Hydro utilizes water reservoirs at varying elevations to generate power, while CAES compresses air underground for later electricity generation. Innovative variations of CAES, like Hydrostor's Advanced-CAES and Highview Power's Liquid Air Energy Storage (LAES), are emerging, offering efficient and scalable storage alternatives. These developments signify a positive shift towards sustainable energy storage solutions for a renewable-heavy grid.