yup it's feasible. It does scale. Here are two links to research that support the feasibility and cost effectiveness of underground gravity storage. https://ww

yup it's feasible. It does scale. Here are two links to research that support the feasibility and cost effectiveness of underground gravity storage. https://www.storage-lab.com/gravity-based-storage https://www.storage-lab.com/gravity-based-storage https://www.osti.gov/biblio/6517343 https://www.osti.gov/biblio/6517343