Each sphere is only worth 5 MW (for 4 hours, totalling 20 MW·h worth of electricity). 80 spheres were not meant to cover the entire base load, but just to make

Each sphere is only worth 5 MW (for 4 hours, totalling 20 MW·h worth of electricity). 80 spheres were not meant to cover the entire base load, but just to make them a relevant factor in the grid.