The peak period is when the highest demand is placed on the grid. In CA, this is typically summer evenings. This sort of tariff would be ideal if you also have

The peak period is when the highest demand is placed on the grid. In CA, this is typically summer evenings. This sort of tariff would be ideal if you also have solar and/or a storage battery, as you can avoid paying the peak rate and take maximum advantage of the off-peak one.