How electricity gets to your house

Electricity is made at power plants and travels to the house through a network of power lines, substations and transformers called the grid. Across the United States, it runs to thousands of miles of high-voltage lines and millions of miles of lower-voltage ones. Those lines connect thousands of power plants to hundreds of millions of customers.

From the plant to the street

Power leaves a plant on high-voltage transmission lines, the ones strung between tall metal towers. High voltage makes carrying electricity over long distances more efficient and less expensive. Near where the power will be used, transformers at substations step the voltage down. Distribution lines then carry the lower-voltage electricity, which is safer to use in homes, along the streets to each customer.

Transformers work in both directions. At the plant they step the voltage up for the long trip, and at substations they step it down for local delivery.

Who runs each part

The company that sells you electricity may be one of three kinds:

• A not-for-profit municipal utility, owned by the city or local government
• An electric cooperative, owned by its members
• A private, for-profit utility owned by stockholders, often called an investor-owned utility

Some utilities make all the power they sell at their own plants. Others buy it from other utilities, power marketers, independent producers or wholesale markets. Some customers buy electricity from a power marketer while the local utility still delivers it. Whoever made the power, the local utility runs the distribution system that connects homes to the grid. That's why outages on your street are reported to the local utility.

Why the grid rarely goes dark all at once

In the lower 48 states the grid has three main interconnections. The Eastern covers the area east of the Rocky Mountains, and the Western runs from the Rockies west. The Electric Reliability Council of Texas covers most of Texas. The supply of electricity has to match demand at every moment. Organizations called balancing authorities keep the two in step within each region. If they fall out of balance, local or widespread blackouts can follow.

The network gives power more than one path, so a single failed line or plant doesn't have to black out a whole region. Mandatory reliability standards cover how utilities plan and run their systems and address security threats to critical electrical infrastructure.

The meter and the smart grid

A smart meter is part of the smart grid. It adds digital equipment to the traditional system, so the utility and the customer can send and receive information. Smart devices on power lines and at substations help a utility pinpoint where an outage or a problem is and fix it faster, sometimes remotely. At home, smart devices can tell you when electricity prices are higher. Where the utility offers time-of-day pricing, you can shift use to cheaper hours.

An annotated example

What to do next

Find the name of the utility that delivers your power. It's on the electric bill, along with any separate supplier. Save its outage number, and check whether the meter is a smart meter. For what each line on the bill charges, see Reading your electric bill. For the panel and the circuits inside the house, see Electrical panel checks and warning signs.