News•November 25, 2014

This Is How the U.S. Power Grid Works

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Credit: DOE

The U.S. electric grid is on the brink of a major change, with rooftops all over the country poised to become adorned with solar panels and the other accoutrements of locally-generated renewable energy, pushing electricity onto the grid while also serving homes.

Right now, the electric grid only works as a one-way street, sending out electricity, but unable to receive it. The big change will be in turning it into a two-way system.

But how does today’s power grid work?

As part of what it called Grid Week in mid-November, the U.S. Department of Energy published a cool new infographic showing how the power grid operates.

The DOE’s graphic and facts about the grid and how it works are especially helpful now that new regulations may soon demand that electric power be generated with fewer fossil fuels and be used more efficiently in an effort to reduce the greenhouse gas emissions that are driving climate change.

The power grids in the U.S. — there are actually three of them — are enormously complex, but they’re traditionally based on a simple idea: Electricity moves in one direction, from a power plant to homes along high voltage transmission lines and lower voltage power lines that distribute electricity to individual homes and neighborhoods.

So, in a nutshell, electricity is generated at a power plant usually far away from the load — the people who are using that power at any given moment. A transformer near the power plant steps up the voltage of the electricity, which is then sent long distances along transmission lines.

Once the transmission lines reach the area they’re serving, the voltage is reduced at another transformer and the electricity follows smaller distribution lines to homes and businesses.

Changes are on the way, however.

There are efforts to build a smart grid in many places, a computerized grid that allows for two-way communication between a utility and customers, allowing power to be used and produced more efficiently.

Microgrids, small grids connecting buildings with a local power source separate from the main grid, are being considered as tools to keep the lights on during disasters.RELATEDClues Show How Green Electricity May Be in 2050
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On its website, the DOE also highlights a few things not commonly known about power grids in the U.S.

For example, the first commercial power grid was built in Lower Manhattan in New York City in 1882.

Today, the three main power grids — one for the eastern U.S., one for the West and one serving most of Texas — include more than 450,000 miles of high-voltage transmission lines. That’s enough to wrap around the Earth’s equator 18 times.

Those are the basics of the power grid today, helpful information to know when tackling climate change demands more discussion of smart grids, microgrids and other innovations in where electricity comes from and how it gets to homes across the country.