Power grid? What is that? [Essay]

The electric grid that exists today, frequently called the
power grid
and serving millions of homes and businesses in North America, began its existence in the late 1800s. Unless you are an engineer—more specifically, a power engineer—it is doubtful that you have ever given a single thought to what is behind the switch whenever you turn on lights, televisions, radios, or other electrical devices. The normal expectation is that, when the switch is thrown on, the lights will come on—every time and always. Outstanding availability and reliability are expected of the system.