The storm clouds that massed over south Charlotte some days last summer threatened to hurl lightning bolts and darken neighborhoods.
But not at Fire Station 24.
Twice last year, sensors at a Duke Energy substation detected potential power losses from storms. In a fraction of a second, an experimental system disconnected the station from power lines and switched to solar-powered backup batteries, then reconnected it to the grid after the threats passed.
The episodes offered a glimpse into the future of electricity, which in the next decade or so could come to you without power lines.
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The Charlotte fire station is part of Duke’s research into self-contained power systems called microgrids. The work is focused in Mount Holly, an old cotton mill town where Duke is tinkering with technology that will upend an industry little changed since Edison’s time.
Duke works behind a chain link fence with two dozen partners known as the Coalition of the Willing, a joking nod to corporations – among them AT&T, General Electric and Siemens – that normally aren’t willing to share trade secrets.
Microgrids typically store energy from solar panels in large batteries. They can serve as backup power when the grid is down, its function at Station 24. They can act as firewalls from cascading power outages that start miles away, and can help utilities make better use of solar or wind power.
They can also work as energy “islands” with no connection at all to power lines. Duke plans to install a small microgrid – solar panels and batteries – as the sole power for a remote communications tower in Great Smoky Mountains National Park. Four miles of power lines to the tower will be removed.
Electric cooperatives are also testing a microgrid on the Outer Banks island of Ocracoke, which has for years relied on a diesel-powered generator. The Tesla batteries and solar panels installed last November could not power the island but will serve as backup power.
Microgrid capacity is expected to more than double in the next three years, the Center for Climate and Energy Solutions says.
“We really want to see where this technology is going and a microgrid, in our estimation, we’re going to have to integrate into the grid,” said engineer Jason Handley of Duke’s Emerging Technology Office.
The Mount Holly test center’s small solar field can generate up to 100 kilowatts of electricity. A 650-kilowatt battery, soon to be supplemented by a 250-kilowatt unit from Concord manufacturer Alevo, stores the energy. An electric vehicle charging station is separately powered by solar panels.
Inside a plain metal building, engineers are trying to weave other pieces of emerging technology into a power industry that’s relied on mechanical knobs, dials and switches for a century.
Lab bays are devoted to an “envision” room of smart appliances, telecommunications, electric vehicles, cybersecurity and real-time grid simulators. An Energy Department grant pays for tests of technology to detect and isolate cyber attacks by assessing the behavior of electronic components.
Within a few years, they say, sensors will routinely detect outages and reroute power before the first customer complains.
Household appliances will choose to operate when electric rates are cheapest. Power from electric vehicles may help power homes or whole communities during emergencies.
A utility repair worker will put on “augmented reality” glasses to work out the job in detail before ever picking up a tool. Hovering drones will scan solar farms for dead cells.
“The microgrid is always doing something, seamlessly,” said Zachary Kuznar, who works in Duke’s Distributed Energy Technology group.
Duke hopes its research at Mount Holly will help it learn how to deploy those technologies, and make them reliable before connecting consumers, as microgrids become more common.
Only part of the energy future is unfolding in Mount Holly. You already carry another piece of it in your pocket: a cell phone.
Embedded with technology that digitally talks to other devices, the phone not only calls your uncle but navigates to his house and uploads a picture of his new puppy. Billions of other devices, from your watch to your car to your clothes dryer, will also communicate with each other on what is called the Internet of Things.
Like a smart phone, “what we want the equipment we place in the field to do is multiple applications,” Handley said.
Making the grid work smartest means making decisions in milliseconds. But because the components connected to the grid use different communication systems, it’s like installing a Honda engine in a Chevrolet.
One of the coalition’s aims is to create a common language in which hardware, electronics and software from different makers can talk to each other. It’s the way a mouse, keypad and monitor made by different manufacturers do for your computer.
That might seem simple to apply to energy. It is not. Duke’s demonstration of “interoperability” among equipment made by a dozen different manufacturers was so groundbreaking that it drew big crowds at a trade show in Orlando last year.
Even simple communication – such as a solar array signaling that a cloud had just passed overhead – once had to be relayed through a control center miles away, costing time and money. Duke is installing small weather stations that could warn of approaching clouds and cue that it’s time to charge or discharge the batteries.
“What we were able to do is take that 45 seconds (of response time) and get it down to one-quarter second,” Handley said.