Researchers have proposed a novel method for repurposing retired coal plants to produce green energy. The concept involves using piles of dirt to store renewable energy as heat. This stored heat can then be used to reactivate the existing machinery within the retired coal plants, effectively transforming them into backup power sources for the electricity grid. This approach offers a potentially cost-effective way to utilize existing infrastructure, reduce waste, and contribute to a more sustainable energy system by integrating renewable energy sources.