Unlike nuclear, that time running at 50% isn't thrown away capital expense, it is merely delayed power output that can be utilized with slightly higher turbine capacity, which is the cheaper part of the capex, and would be needed for higher power output anyway.
For nuclear, adding thermal storage for time shifting would be the most equivalent to what's happening with geothermal storage, but with geothermal there's no additional capex or engineering needed.
For nuclear, adding thermal storage for time shifting would be the most equivalent to what's happening with geothermal storage, but with geothermal there's no additional capex or engineering needed.