1878

Power Grid

In 1878, at the Paris World’s Fair, visitors marveled at the Yablochov arc lamps (patented by Pavel Yablochov in 1876) powered by Zénobe Gramme dynamos. This was an example of an early commercial system of high-voltage power—the kind of power grid that exists invisibly behind the scenes around the world today.

It is possible to imagine a society where there is no power grid—where every home and business generates its own power on-site. But this approach has efficiency problems. A big power plant can realize economies of scale when purchasing fuel and can apply significant resources to emission controls. Advanced technologies like nuclear power are not possible without a big power plant. And site-specific power sources like hydropower, solar power, and wind turbines only really make sense if there is a grid. A power grid can also improve reliability. When a big power plant needs to go offline for maintenance, other power plants in the area use the grid to make up the load.

It is amazing to realize that the power grid has only two key components: wire and transformers. Transformers can multiply voltages up and down. For long distance transmission, transformers boost the voltage to 700,000 volts or more. Once the power arrives at its destination, transformers step down the voltage. It might travel at 40,000 volts in a community, and then 3,000 volts in a neighborhood. At your house, a final transformer brings it to 240 and 120 volts for use in your wall outlets and light switches.

The grid is not perfect, and occasionally we see widespread blackouts. On a sweltering summer day with the whole grid running at peak loading, a failure in a key transmission line can cause an irresolvable problem. Other lines try to pick up the load from the failed line, but they overload and fail. A ripple effect can leave several states in the dark. Engineers are working on new architectures to prevent this problem as well. Once perfected, the grid will be even more invisible.

SEE ALSO Hoover Dam (1936), Itaipu Dam (1984), Smart Grid (1998), Alta Wind Energy Center (2010), Ivanpah Solar Electric Generating Center (2014).

Without a power grid, energy would have to be generated on site.