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MIT scientists propose power storage using cement blocks
(www.datacenterdynamics.com)
This is a most excellent place for technology news and articles.
For a basement with a 5-inch slab and exterior walls are 8 inches, 8ft high and also concrete... Then 45 cubic meters is about what you'd need.
Of course, your basement walls are about as electrically grounded as it gets, so I doubt you'd be able to store power in them. One leak and you're discharging all that power into the groundwater.
So, feasible amount. Just needs isolating and could replace expensive batteries for solar?