The Grid: Electrical Infrastructure for a New Era

by Gretchen Bakke

Still other things are culturally predictable. Between five and six P.M., Americans tend to come home from work. When this happens we use all kinds of electrical devices we weren’t using before: big TVs, microwaves, washing machines, and garage door openers. On average we open our fridge nine times in the hour before dinner. All of these things add up to a fairly substantial jump in demand from just after the close of the workday until about ten P.M., at which point demand begins a slow downward slide that ends at four A.M.—the hour of minimum load. To meet this steady bump in demand, power plants ramp up everywhere in America just before five P.M. Unfortunately, it is also when the wind tends to slow down and, at certain times of year, when the sun starts its setting, making renewables without backup storage the least useful means of producing power at the most necessary moment of the day.