Private US Company Powers 60 Million
July 31, 2012
Every day, as dusk falls over the United States, millions of street
lights blink on in towns and cities across the country.
These quiet moments require a vast, unseen balancing act, because
electricity demand and supply must be matched every second.
Perhaps no one carries more responsibility for getting this balance
right than PJM Interconnection, a private company which manages the flow
of electricity to 60 million customers in 13 mid-Atlantic U.S. states.
As one of the oldest businesses of its kind, PJM often advises
neighboring regions or developing nations on how to manage complex
energy-transmission systems. Its success is of special note in a week
when a series of power black-outs have brought much of India to a
PJM's control center, in Valley Forge, Pennsylvania, is like a traffic
officer for the region's electric power grid. Every day, it ensures that
more than 1,600 power plants share more than 100,000 kilometers of
transmission lines fairly, efficiently and reliably.
To do this, PJM runs an electricity marketplace where power plants
declare the lowest price for which they would generate power the next
day. Based on these prices and ever-changing demand and transmission
line sizes, PJM tells each power plant exactly when to turn on or off.
“We’re looking in at one of the two PJM control rooms,” says Mike
Bryson, PJM’s director of operations. "They’re both staffed 24 hours a
day, seven days a week. If one of the rooms is disabled, the other can
Centers of power
Bryson runs the company’s twin command centers. Each windowless
underground room contains 10 desks, an American flag and a 20-meter-wide
screen crowded with constantly-updated data.
At the screen’s center is a multicolored map, which shows, "the bulk
electric system, with generators on the system, direction of flow on all
the transmission lines, and then the red dots on there show you the
generators," Bryson says. "Red is online. Green is offline.”
That's right, red is on. Green is off.
“That’s electrical engineering," Bryson says. "It’s the opposite of
Scorching summer days can be the hardest to manage. With millions of air
conditioners driving electricity demand up, PJM will sometimes offer
generators 50 times the usual non-peak price for electricity.
“That’s really telling everybody ‘Hey, we need everybody on because we
don’t want to lose any customers,’” Bryson says.
Planning ahead is more important than ever in the digital age.
"The reliability of electricity is much more important than it was...25
years ago, before we all had computers and the Internet and all kinds of
electronic devices," says Terry Boston, PJM’s President and CEO. "We
keep building... new infrastructure each and every year to make sure
Just as America’s energy needs are changing, so are its energy sources.
Coal, hydro and nuclear are still key, but natural gas use is growing
rapidly. PJM is also working to integrate wind and solar, even though
these renewable sources produce power at varying rates.
“When I started my career, I was writing software to optimize the
generators to match the load," says Boston. "Now I’m trying to match the
load to the variable generators.”
For instance, when supply gets tight, PJM can now alert colleges or
factories to turn off equipment. That’s called “demand response” and
Bryson is glad to have that flexibility.
have, going into this summer, over 9,000 megawatts of demand response
throughout the system," Bryson says. "That’s the equivalent of nine
That sort of highly-interactive communication has its risks. And, in
recent years, PJM’s focus on security has expanded to address the
possibility of sophisticated Internet-based attacks on the transmission
But as complex as the work at PJM can be, there’s one display that’s
simple and it’s Bryson’s favorite.
“It’s what I call the control panel," he says. "The idea is to keep that
little green ball in the middle. Keep it in the blue. If it goes into
the red, you want to steer it back in. We do that by raising and
lowering generation. If we had a joystick to move it, it would be a lot
Yet every evening as the street lights blink on again in Chicago,
Washington, D.C. and all the towns in between, it’s a reminder that -
even without a joystick - PJM’s operators have the region’s power grid
well in hand.