Where electricity comes from

Electricity is generated at power plants. You know that already. But to really understand how it gets to your house—and why you can count on it getting there reliably—you have to understand that our electric system is more complicated than it looks. The electric grid isn't just about you and your connection to a power plant. There are lots of thing that have to happen behind the scenes to make sure your refrigerator stays cold and your lights turn on.

One of the key components in the system are grid control centers—places where technicians manage electric supply and electric demand. This is important. In order for the grid to operate without blackouts there must always be an almost perfect balance between supply and demand. The grid doesn't really include any electrical storage, so that balance has to be maintained manually—on a minute-by-minute basis—by grid controllers who work 24 hours a day, 7 days a week. This isn't the best way to make a grid work, but it's what we've done since the earliest days of electricity.

In the April issue of Discover, I take readers on a tour of one of these grid control centers.

1. A River Runs Through It
 Power plants generate electricity, but they do not create anything from scratch. Instead, generators take electrons, which normally orbit the nucleus of an atom, and force them to move independently through the grid’s closed path. When too many electrons build up or their numbers in the system (monitored here) fall too low, you get a total loss of power: a blackout.

Read the rest of story at Discover

Meet the grid controllers and learn more about the inner workings of our electric system in my book, Before the Lights Go Out.

• [David B]

  As someone who works for a paid-information company that covers the energy markets, I was interested in learning more about the US grid because America is one of the few countries with a liberalized (at least partially) power market. But the link doesn’t take you to an article, it takes you to a photo with captions. Would have liked to learn more.

  • [Maggie Koerth-Baker]

    Hey David, 

    The piece for Discover was pretty short. The book has a lot more detail. That’s why I included links to both. 

• [bzishi]

  No. Nobody monitors electrons and they don’t build up (unless you are talking about capacitors). This is especially true since the grid tends to be AC. They oscillate about a position.  In any case, even if it were DC, it is not the buildup or loss of electrons that causes a blackout or brownout (they don’t buildup, they just move)–it is the loss of voltage control on the grid.  If you have a constant load and your voltage drops, the current will increase which will trip breakers, damage equipment, or take generating stations off line. If a generating station goes offline you have less ability to control your grid voltage. When that happens you have to drop load to maintain the grid voltage (brownout an area) or lose the grid (blackout).

  It is actually more complicated than this, but the idea of a constant or increasing load with a loss of grid voltage causing blackouts or brownouts is generally how it works.

  • [william beaty]

    Yeah, K6 textbooks teach that electric current is a flow of energy.  Once that misconception is in your brain, no explanation makes any sense.  The books do the equivalent to trying to simplify an explanation of sound by teaching us that sound and wind are the same thing.

    To grasp the basic physics of circuits, usually you have to do a whole bunch of mythbusting.   That, and develop an extreme distrust of any physics you were taught in grade school!  :)

    • [Ultan]

      Bill is apparently too humble to link to his own site, which has the best explanations of how electricity really works.
      All his articles are highly recommended.
      http://amasci.com/miscon/elect.html

• [Keith Tyler]

  And yet if you want to power your home from solar you run into none of these problems because it’s factored into the system.

  Sometimes you have to tear everything out and rebuild from scratch. Otherwise eventually all the jury-rigs, duct tape and baling wire will simply knock the system over.

  • [Maggie Koerth-Baker]

    Not sure what you’re saying, Keith, but solar doesn’t eliminate the issue of supply and demand balance. Can you explain what you mean a little more? Right now, it sounds like you’re very misinformed. 

• [Doug Lucchetti]

  Great work…thanks for the insights.

• [william beaty]

  Actually, the number of electrons in the system doesn’t change: blackouts occur when the “charge pumps” fail and the electrons of the metal wires stop wiggling.  In an AC system, the electrons move back and forth by a few microns, while only the electrical energy moves rapidly forward.  The analogy to sound waves traveling in a fluid-filled pipe is somewhat accurate.   Don’t forget that two things flow in circuitry: the path for electric charges is in a complete circle, while electrical energy flows one-way from a source to a sink.

  In other words, electric current is not a flow of energy.    We do teach kids the difference between sound and wind, but we don’t teach them the electrical equivalent: the difference between energy flow versus current.

  The common misconceptions are widespread in K-12 curricula, and aren’t very well debunked when/if we take physics classes (although the CASTLE and the Smithsonian packages do a pretty good job.)   The problem lies in misunderstanding the nature of amperes versus watts.   Even more central: the problem is in defining “electricity” as a form of energy, but then creating a complete contradiction by defining “current” as a flow of electricity.   No, if electric current is a flow of electricity, then we’re using the obsolete Maxwell/Faraday/Einstein definition of the word “electricity” and not the modern one.

  Example: JC Maxwell defines “electricity” as charge, where an electric current is a flow of electricity.  Also he specifically shows that electricity is not a form of energy, see material from 1891 “Treatise”:  http://amasci.com/miscon/maxwell.html#max

• [drowse03]

  Nice! I actually work for an electric distribution Co-Operative here in Texas and its neat to see what an operations center for ERCOT looks like compared to our small little Dispatch Operations center with three people at most during the day..

• [Todd Radel]

  Hi Maggie. This picture brings back memories for me. My dad worked for PJM Interconnection for almost 40 years. When I was a kid he used to take me on tours of the building. I loved the control center and mainframe room. The security arrangements also fascinated me. I’ve been meaning to buy a copy of your book to share with my dad. Thanks for the memories!

• [Lucy Gothro]

  Thank you so much for publishing an explanation that is informative without being patronizing, as many such explanations tend to be.