In both scenarios, the amount of electricity supplied through the power grid is lower during peak periods, which improves reliability, reduces rates by avoiding the use of high-priced power plants during peak hours and delays capital intensive infrastructure investments needed to maintain the grid.
The glut exacerbates the inefficiency by forcing the utilities to rely on dirtier and less efficient sources of power to meet peak demand rather than simply redirecting surplus power from low demand to high-demand markets.
Since John is still doing his laundry during peak load hours, the utility is paying top dollar in infrastructure costs and high-cost backup power plants.