Peak Energy, a US startup, is leading the way in sodium-ion battery technology, offering advantages over lithium-ion systems in terms of cost, supply chain security, scale, and safety. Partnering with Jupiter Power, they are set to build the world's largest sodium-ion battery energy storage system, delivering a 720-megawatt system in 2027. This development comes as coal power plants in the US face challenges from falling costs of renewable energy and energy storage systems, leading to scheduled retirements. The shift towards cleaner energy sources is driven by factors such as grid conditions, rising electricity demand, and the need for more reliable and cost-effective energy solutions, highlighting the potential for reliable and economical energy storage systems to support the transition to renewable energy in the US.