There have been recent advances in sand batteries to store heat. Use the excess energy to heat the sand. Then pull heat from it in the winter to heat the hous

There have been recent advances in sand batteries to store heat. Use the excess energy to heat the sand. Then pull heat from it in the winter to heat the house. Unsure if this would scale down to personal usage. https://www.bbc.com/news/science-environment-61996520 https://www.bbc.com/news/science-environment-61996520